I. CALORIMETRY CALORIMETRY

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "I. CALORIMETRY CALORIMETRY"

Transcription

1 CALORIMETRY I. CALORIMETRY If the process (e.g. chemical reaction, phase conversion) requires heat to proceed, it is said to be endothermic. For endothermic process, q > 0. If the process (e.g. chemical reaction, phase conversion) evolves heat, it is said to be exothermic. For exothermic process, q < 0. Letter "q" denotes the heat flow between surroundings and the system. We often need to know the magnitude and direction of the heat flow for a process. The method by which the heat flow is measure is termed calorimetry. If you would like to measure the heat flow in a process, you must have an isolated vessel called a calorimeter. The most commonly used calorimeters base on so called Dewar s vessel. However one can use as simple systems as e.g. two Styrofoam coffee cups placed inside the other and covered with a lid. In all our experiments the calorimeter will be filled with water the temperature of which will be measured. The calorimeter and water are called surroundings and the substance/s undergoing an investigated process is/are called system. The specific heat (C) of a substance is that amount of heat which is required to increase the temperature of one gram of a substance by one Kelvin (or one degree Celsius). The heat capacity of the calorimeter (K), sometimes denoted as calorimeter constant, is that amount of heat which is required to increase the temperature of calorimeter by one Kelvin (or one degree Celsius). Note the difference between specific heat and heat capacity. We cannot measure heat directly. Instead, we measure the change in temperature of the water. The equation which relates heat flow, temperature change and specific heat is: Where m is the mass of the substance, C is the specific heat, and ΔT is the change in temperature (Tfinal-Tinitial). This equation can be used to calculate the amount of heat gained or lost by water on proceeding the investigated process. For endothermic process, q > 0:

2 Because the calorimeter is a closed system, all the heat gained by the changing system has to be lost by water. Therefore we can write the following equation: For exothermic process, q < 0: Because the calorimeter is a closed system, all the heat evolved by the changing system has to be gained by water. Therefore we can write the following equation: These equations imply that the heat lost/gained by the system is equal and opposite to the heat gained/lost by the water. One should interpret the negative sign to mean "opposite to". If we take into account that the real calorimeter is a setup consisting of dewar vessel, water, stirrer, termometer, the product m w C w in equations (3) and (4) should be replaced with the heat volume of calorimeter (K), i.e.: Equations (4a) and (5a) can be used to calculate heat lost/gained by the system (q process ) when we know the values of K and ΔT w or to calculate K, when we know the values of q process and ΔT w.

3 I.A. HEAT OF MELTING OF ICE Purpose: to learn the principles of calorimetry measurements, to determine the heat of melting of ice Procedure: 1. Weigh the empty Dewar vessel. 2. Fill the Dewar vessel with 50.0 ml of ~30 C water and weigh the vessel. Record the mass. 2. Measure and record the initial temperature of the water. 3. Add 2-3 ice cubes to the water. Stir gently with the temperature probe. Before the ice is completely melted, add another ice cube. 4. Continue adding ice cubes in this manner until the temperature reaches a plateau. Record the final temperature. 5. Carefully pull out the remaining ice cubes, allow the water to drop back into the vessel. 6. Weigh the vessel and record the mass. Calculations: 1. Find the mass of water originally in the cup. 2. Calculate the amount of heat the water gave to the ice cubes. Use the mass of water and the change in temperature. 3. Calculate the mass of ice which melted. 4. The amount of heat released by the water (and calculated in step 2) is equal to the amount of heat absorbed by the ice. Knowing this and the mass of the ice which melted, calculate the heat of melting of ice in units of J/g. Recalculate it to kj/mole of ice. 4. Find the error in %. Include in the introduction the definition of heat, the definition of heat of melting, describe the calorimetry and how it works. Give the accepted values for the heat of melting of ice, in both kj/mole and J/g. Make sure all equations used are clearly shown in your calculations.

4 I.B. HEAT OF SOLUTION OF A SOLID Purpose: to learn the principles of calorimetric measurements, to observe the dependence of the heat of solution on the concentration of the solution formed. The process of solid dissolution in water is always associated with energy change (heat). The dissolving process itself is a two-step process. The first step, that of breaking down the solid crystal, is endothermic. The second step, that of hydrating the individual particles released into the solvent, is exothermic. For an ionic compound, ionic bonds are broken while ion-dipole interactions appear and the ionic compound dissociates into ions, negative and positive ones. Ion-dipole interactions appear when the slightly positive hydrogen atoms of water molecule are attracted to the negative ions, and the slightly negative oxygen atoms of the water molecule are attracted to the positive ions. We talk about the hydration of ions. The overall heat of solution depends on the relative amounts of energy involved in the two individual steps. Hydration of ions involves a complex redirection of forces of attraction and repulsion. Before the solution forms, water molecules are attracted only to each other; and positive and negative ions have only each other in the crystal to be attracted to. In the solution, the ions have water molecules to take the places of their oppositely charged counterparts; and water molecules find ions more attractive then even other water molecules. In this experiment, you will determine the heats of solution for the dissolving of the same amount of a salt (e.g. ammonium nitrate, sodium acetate, sodium thiosulphate) in different amounts of water using a Dewar vessel as a calorimeter. Procedure: 1. Accurately weigh a sample of solid salt of approximately 5 grams. 2. Add exactly 500 ml of water to the Dewar vessel. 3. Stir the water briefly with the stirrer and start recording the temperature every 30 s. 4. Dissolve the solid in the water, stirring continuously, and continue recording the temperature. 5. Rinse out the vessel, dry it thoroughly, and repeat the experiment twice adding 250 ml of water.

5 Calculations: 1. Calculate the following for each part of the experiment. a) the temperature change of the water. (Hint: make a plot of temperature versus time of observation.) b) the quantity of heat gained (or given off) by the water during the dissolving, K=2,5 kj/deg. c) the number of moles of salt used. e) the molar heat of solution, i.e. the quantity of heat involved per mole of salt dissolved. 2. Find the accepted values for the molar heats of solution for these solids in a chemistry handbook, and calculate the percentage error of your experimental values. Observe whether the numbers given in a handbook concern the molar ratio of salt and water. Questions: 1. Write an equation for the dissolving process for each salt adding the heat term to each equation. 2. Describe each step of the two-step process of dissolution using both words and a diagram. Designate each step as endothermic or exothermic. 3. Which of these individual steps shows the higher absolute value?

6 I.C. HEAT OF NEUTRALIZATION REACTION The neutralization reaction The reaction of sulfuric acid with sodium base can be written as follows: or in an ionic form: It appears that the reaction proceeds between hydrogen cations and hydroxyl anions and results in the formation of water. Definition: the neutralization reaction of strong acid with strong base is the reaction of hydrated hydrogen cations with hydrated hydroxyl anions resulting in the formation of water: Heat of this reaction does not depend on the type of acid or base and equals kj per mole of water formed. Procedure: 1. Fill a glass ampoule with ca. 3 g of sulfuric acid (you should know the exact mass of acid). Ask TA for assistance. 2. Calculate what volume of NaOH water solution (20% w/w) is needed to neutralize the amount of acid you have in an ampoule. Ask TA for the acceptance of your calculations. 3. Place the calculated volume (increased by 30%) of NaOH solution into an Dewar vessel and add water so that the final volume of the obtained solution would be exactly 500 ml. 4. Mount the ampoule containing sulfuric acid in the holder provided with the calorimter setup. Connect stirrer to the electric engine. Place properly the temperature probe in Dewar vessel. 5. Stir the water briefly and start recording the temperature every 30 s. 6. Allow sulfuric acid to dissolve in the solution by breaking smoothly the glass ampoule. Do not stop stirring and continue recording the temperature until its value reaches plateau.

7 CALORIMETRY 7. Dismount carefully the calorimeter setup. Rinse Dewar vessel with water. Rinse the broken ampoule with water and give it back to the TA. Calculations: 1. Make a plot of temperature versus time and read out the temperature change (increase). 2. Calculate the heat flow observed on dissolving sulfuric acid in the water solution of sodium base. 3. Note that the observed heat flow results from the two processe taking place simultaneousely in an Dewar vessel. They are: (i) dissolution od sulfuric acid in water and (ii) neutralization reaction: therefore 4. Find the heat of sulfuric acid solution in water in a chemical handbook. Calculate the observed heat of neutralization taking the heat capacity of the calorimetric setup a 2.5kJ/deg. Hint: heat values shown in tables refer to one mole of sulfuric acid, while you have used much lower amount. 5. Calculate the heat of neutralization for one mole of water formed. Hint: From one mole of fully neutralized sulfuric acid two moles of water are formed. 6. Compare the obtained molar value of the heat of neutralization with accepted value. Comment possible differences.

8 I.D. DETERMINING THE HEAT CAPACITY OF CALORIMETER Purpose: to learn the principles of calorimetry measurements, to determine the heat capacity of calorimeter, i.e to calibrate the calorimeter Procedure: 1. Fill a glass ampoule with ca. 2,5-3 g of sulfuric acid (you should know the exact mass of acid). Ask TA for assistance. 2. Add exactly 500 ml of water to the Dewar vessel. 3. Place the ampoule, stirrer and thermometer probe on their places. 4. Stir the water briefly with the stirrer and start recording the temperature every 30 s. 5. Allow acid to dissolve in water by gentle breaking the glass ampoule. Continue recording temperature until its value reaches plateau. 6. Dismount carefully the calorimeter setup. Rinse Dewar vessel with water. Rinse the broken ampoule with water and give it back to the TA. 7. Repeat steps 2 6 taking 5-6 g of sulfuric acid. Calculations: 1. Make a plot of temperature versus time and read out the temperature change (increase). 2. Find the heat of sulfuric acid solution in water in a chemical handbook and calculate the heat loss (q process ) during the process of acid dissolution in water. Hint: heat values shown in tables refer to one mole of sulfuric acid, while you have used much lower amount 3. Calculate the heat capacity of the calorimeter. 4. Compare the result of the two experiments. Does the heat capacity of the calorimeter depend on the amount of acid taken? Haw could you easily change the heat capacity of your calorimeter?

L q + w. CHM 1041 Thermochemistry Heats of Solution (Reaction) J. Bieber. Section: Date:

L q + w. CHM 1041 Thermochemistry Heats of Solution (Reaction) J. Bieber. Section: Date: CHM 1041 Thermochemistry Heats of Solution (Reaction) J. Bieber Name: Partner: Section: Date: To study quantitatively the heat of solution when (1) a salt dissolves in water and (2) to study the heats

More information

Procedure. Day 1 - Calibration of the Calorimeter. (Part I) The Heat Capacity of the Calorimeter.

Procedure. Day 1 - Calibration of the Calorimeter. (Part I) The Heat Capacity of the Calorimeter. Thermochemistry Experiment 10 Thermochemistry is the study of the heat energy involved in chemical reactions and changes of physical state. Heat energy is always spontaneously transferred from hotter to

More information

q = (mass) x (specific heat) x T = m c T (1)

q = (mass) x (specific heat) x T = m c T (1) Experiment: Heat Effects and Calorimetry Heat is a form of energy, sometimes called thermal energy, which can pass spontaneously from an object at a high temperature to an object at a lower temperature.

More information

7 THERMOCHEMISTRY: HEAT OF REACTION

7 THERMOCHEMISTRY: HEAT OF REACTION 7 THERMOCHEMISTRY: HEAT OF REACTION Name: Date: Section: Objectives Measure the enthalpy of reaction for the decomposition of hydrogen peroxide Measure the heat capacity of a Styrofoam cup calorimeter

More information

Unit 27 Heat of Neutralization Calorimetry

Unit 27 Heat of Neutralization Calorimetry Unit 27 Heat of Neutralization Calorimetry When reactions occur, energy is always involved. Reactions that absorb energy are called "endothermic" reactions. Reactions that give off energy are called "exothermic"

More information

Heat of Neutralization

Heat of Neutralization Cautions HCl and NaOH are corrosive and toxic Purpose The purpose of this experiment is to determine the heat of neutralization for a reaction between a strong acid and a strong base. Introduction Chemical

More information

Transfer of heat energy often occurs during chemical reactions. A reaction

Transfer of heat energy often occurs during chemical reactions. A reaction Chemistry 111 Lab: Thermochemistry Page I-3 THERMOCHEMISTRY Heats of Reaction The Enthalpy of Formation of Magnesium Oxide Transfer of heat energy often occurs during chemical reactions. A reaction may

More information

Calorimeter: A device in which the heat associated with a specific process is measured.

Calorimeter: A device in which the heat associated with a specific process is measured. 1 CALORIMETRY p. 661-667 (simple), 673-675 (bomb) Calorimeter: A device in which the heat associated with a specific process is measured. There are two basic types of calorimeters: 1. Constant-pressure

More information

DETERMINING THE ENTHALPY OF FORMATION OF CaCO 3

DETERMINING THE ENTHALPY OF FORMATION OF CaCO 3 DETERMINING THE ENTHALPY OF FORMATION OF CaCO 3 Standard Enthalpy Change Standard Enthalpy Change for a reaction, symbolized as H 0 298, is defined as The enthalpy change when the molar quantities of reactants

More information

Thermochemistry: Enthalpy of Reaction Hess s Law

Thermochemistry: Enthalpy of Reaction Hess s Law Thermochemistry: Enthalpy of Reaction Hess s Law Objective Demonstrate Hess s Law for determining the enthalpy of formation for MgO by measuring temperature change for several reactions. Introduction The

More information

Heats of Transition, Heats of Reaction, Specific Heats, and Hess s Law

Heats of Transition, Heats of Reaction, Specific Heats, and Hess s Law Heats of Transition, Heats of Reaction, Specific Heats, and Hess s Law GOAL AND OVERVIEW A simple calorimeter will be made and calibrated. It will be used to determine the heat of fusion of ice, the specific

More information

Lab 9. Hess s Law. Reaction B. NaOH (s) + HCl (aq) NaCl (aq) + H 2 O (l) Reaction C. NaOH (aq) + HCl (aq) NaCl (aq) + H 2 O (l)

Lab 9. Hess s Law. Reaction B. NaOH (s) + HCl (aq) NaCl (aq) + H 2 O (l) Reaction C. NaOH (aq) + HCl (aq) NaCl (aq) + H 2 O (l) Lab 9. Hess s Law Prelab Assignment Before coming to lab: This exercise does not require a report in your lab notebook. Use a pen to record your data, observations, calculations and analysis in the spaces

More information

HEATS OF REACTION. Name: Chemistry 117 Laboratory University of Massachusetts Boston LEARNING GOALS

HEATS OF REACTION. Name: Chemistry 117 Laboratory University of Massachusetts Boston LEARNING GOALS Name: Chemistry 117 Laboratory University of Massachusetts Boston HEATS OF REACTION LEARNING GOALS 1. Become familiar the technique of calorimetry to measure heats of reaction 2. Become familiar with the

More information

Name: Introduction to Calorimetry

Name: Introduction to Calorimetry Name: Introduction to Calorimetry Purpose: The goal of this experiment is to gain experience in the practice of calorimetry; the main method by which chemists measure the energy changes in chemical reactions.

More information

Name Date Class THERMOCHEMISTRY. SECTION 17.1 THE FLOW OF ENERGY HEAT AND WORK (pages 505 510)

Name Date Class THERMOCHEMISTRY. SECTION 17.1 THE FLOW OF ENERGY HEAT AND WORK (pages 505 510) 17 THERMOCHEMISTRY SECTION 17.1 THE FLOW OF ENERGY HEAT AND WORK (pages 505 510) This section explains the relationship between energy and heat, and distinguishes between heat capacity and specific heat.

More information

Chapter 5 Thermochemistry

Chapter 5 Thermochemistry Chapter 5 Thermochemistry I. Nature of Energy Energy units SI unit is joule, J From E = 1/2 mv 2, 1J = 1kg. m 2 /s 2 Traditionally, we use the calorie as a unit of energy. 1 cal = 4.184J (exactly) The

More information

EXPERIMENT 12N CALORIMETRY

EXPERIMENT 12N CALORIMETRY EXPERIMENT 12N CALORIMETRY FV 7/28/2016 MATERIALS: PURPOSE: OBJECTIVES: Styrofoam cup and lid, stir bar, magnetic stir plate, digital thermometer, 250 ml beaker, two 100 ml graduated cylinders, aluminum

More information

Experiment 6 Coffee-cup Calorimetry

Experiment 6 Coffee-cup Calorimetry 6-1 Experiment 6 Coffee-cup Calorimetry Introduction: Chemical reactions involve the release or consumption of energy, usually in the form of heat. Heat is measured in the energy units, Joules (J), defined

More information

Chapter 3 Test Practice DO NOT WRITE ON THIS PRACTICE EXAM

Chapter 3 Test Practice DO NOT WRITE ON THIS PRACTICE EXAM Chapter 3 Test Practice MOORE DO NOT WRITE ON THIS PRACTICE EXAM 1. A sample of an element has a mass of 34.261 grams and a volume of 3.8 cubic centimeters. To which number of significant figures should

More information

2 To use calorimetry results to calculate the specific heat of an unknown metal. 3 To determine heat of reaction ( H) from calorimetry measurements.

2 To use calorimetry results to calculate the specific heat of an unknown metal. 3 To determine heat of reaction ( H) from calorimetry measurements. Calorimetry PURPOSE To determine if a Styrofoam cup calorimeter provides adequate insulation for heat transfer measurements, to identify an unknown metal by means of its heat capacity and to determine

More information

CHM111 Lab Enthalpy of Hydration of Sodium Acetate Grading Rubric

CHM111 Lab Enthalpy of Hydration of Sodium Acetate Grading Rubric Name Team Name CHM111 Lab Enthalpy of Hydration of Sodium Acetate Grading Rubric Criteria Points possible Points earned Lab Performance Printed lab handout and rubric was brought to lab 3 Safety and proper

More information

Exp 13 Volumetric Analysis: Acid-Base titration

Exp 13 Volumetric Analysis: Acid-Base titration Exp 13 Volumetric Analysis: Acid-Base titration Exp. 13 video (time: 47:17 minutes) Titration - is the measurement of the volume of a standard solution required to completely react with a measured volume

More information

Thermodynamics Experiment The Enthalpy of H 2 O 2 Decomposition in Aqueous Solution

Thermodynamics Experiment The Enthalpy of H 2 O 2 Decomposition in Aqueous Solution Thermodynamics Experiment The Enthalpy of H 2 O 2 Decomposition in Aqueous Solution OBJECTIVES 1. To illustrate the use of calorimetry in the experimental measurement of thermodynamic data. 2. To illustrate

More information

Thermochemistry: Calorimetry and Hess s Law

Thermochemistry: Calorimetry and Hess s Law Thermochemistry: Calorimetry and Hess s Law Some chemical reactions are endothermic and proceed with absorption of heat while others are exothermic and proceed with an evolution of heat. The magnitude

More information

ph: Measurement and Uses

ph: Measurement and Uses ph: Measurement and Uses One of the most important properties of aqueous solutions is the concentration of hydrogen ion. The concentration of H + (or H 3 O + ) affects the solubility of inorganic and organic

More information

Experiment 7: Enthalpy of Formation of Magnesium Oxide

Experiment 7: Enthalpy of Formation of Magnesium Oxide Experiment 7: Enthalpy of Formation of Magnesium Oxide Objective: In this experiment, a simple calorimeter will be constructed and calibrated, and Hess' law of constant heat summation will be used to determine

More information

CALORIMETRY AND HESS LAW: FINDING H o FOR THE COMBUSTION OF MAGNESIUM

CALORIMETRY AND HESS LAW: FINDING H o FOR THE COMBUSTION OF MAGNESIUM Experiment 12J FV 7/16/06 CALORIMETRY AND HESS LAW: FINDING H o FOR THE COMBUSTION OF MAGNESIUM MATERIALS: Styrofoam coffee cup and lid, thermometer, magnetic stirrer, magnetic stir bar, 50-mL and 100-

More information

CHEMISTRY 3310 PROBLEM SHEET #4

CHEMISTRY 3310 PROBLEM SHEET #4 CHEMISTRY 3310 PROBLEM SHEET #4 1. The specific heats of a number of materials are listed below. Calculate the molar heat capacity for each. (a) gold, (b) rust (Fe 2 O 3 ) (c) sodium chloride 2. Calculate

More information

Endothermic and exothermic reactions. Performing different measurements to examine which reactions release or consume heat.

Endothermic and exothermic reactions. Performing different measurements to examine which reactions release or consume heat. Objective The purpose of this activity is to recognize chemical reactions as endothermic and exothermic. Students will then create a hypothesis and proceed to test it using the Labidisc external temperature

More information

FIGURE L20.1. Introduction

FIGURE L20.1. Introduction Lab 20. Enthalpy Change of Solution: How Can Chemists Use the Properties of a Solute to Predict If an Enthalpy Change of Solution Will Be Exothermic or Endothermic? Introduction Thermodynamics is the study

More information

Chemistry 1215 Experiment #10 The Reaction of Zinc and Iodine: The Combination of Two Elements

Chemistry 1215 Experiment #10 The Reaction of Zinc and Iodine: The Combination of Two Elements Chemistry 1215 Experiment #10 The Reaction of Zinc and Iodine: The Combination of Two Elements Objective The objective of this experiment is to perform a combination reaction by reacting elemental zinc

More information

HEAT OF FORMATION OF AMMONIUM NITRATE

HEAT OF FORMATION OF AMMONIUM NITRATE 303 HEAT OF FORMATION OF AMMONIUM NITRATE OBJECTIVES FOR THE EXPERIMENT The student will be able to do the following: 1. Calculate the change in enthalpy (heat of reaction) using the Law of Hess. 2. Find

More information

Calorimetry and Thermochemistry

Calorimetry and Thermochemistry CHEM 121L General Chemistry Laboratory Revision 1.3 Calorimetry and Thermochemistry Learn how to measure Heat flow. Learn about the Specific Heat of substances. Learn about Exothermic and Endothermic chemical

More information

Chapter 6: Thermochemistry (Chemical Energy) (Ch6 in Chang, Ch6 in Jespersen)

Chapter 6: Thermochemistry (Chemical Energy) (Ch6 in Chang, Ch6 in Jespersen) Chapter 6: Thermochemistry (Chemical Energy) (Ch6 in Chang, Ch6 in Jespersen) Energy is defined as the capacity to do work, or transfer heat. Work (w) - force (F) applied through a distance. Force - any

More information

Observe and measure the effect of a solute on the freezing point of a solvent. Determine the molar mass of a nonvolatile, nonelectrolyte solute

Observe and measure the effect of a solute on the freezing point of a solvent. Determine the molar mass of a nonvolatile, nonelectrolyte solute Chapter 10 Experiment: Molar Mass of a Solid OBJECTIVES: Observe and measure the effect of a solute on the freezing point of a solvent. Determine the molar mass of a nonvolatile, nonelectrolyte solute

More information

Chemistry 1215 Make up Lab Enthalpy of Neutralization

Chemistry 1215 Make up Lab Enthalpy of Neutralization hemistry 1215 Make up Lab Enthalpy of Neutralization Objective In this experiment you will determine the molar enthalpy of neutralization of an acid. Introduction The study of energy and its transformations

More information

Enthalpy of Neutralization. Introduction

Enthalpy of Neutralization. Introduction Enthalpy of Neutralization Introduction Energy changes always accompany chemical reactions. If energy, in the form of heat, is liberated the reaction is exothermic and if energy is absorbed the reaction

More information

Heat of Solution. Purpose To calculate the heat of solution for sodium hydroxide (NaOH) and ammonium nitrate (NH 4 NO 3 )

Heat of Solution. Purpose To calculate the heat of solution for sodium hydroxide (NaOH) and ammonium nitrate (NH 4 NO 3 ) Heat of Solution Purpose To calculate the heat of solution for sodium hydroxide (NaOH) and ammonium nitrate (NH 4 NO 3 ) Background For a given solute, the heat of solution is the change in enerrgy that

More information

CHEMISTRY 110 Assignment #3 - answers 2011.

CHEMISTRY 110 Assignment #3 - answers 2011. 1. Titanium metal is used as a structural material in many high tech applications such as in jet engines. What is the specific heat of titanium in J/() if it takes 89.7 J to raise the temperature of a

More information

Experiment 14 - Heats of Reactions

Experiment 14 - Heats of Reactions Experiment 14 - Heats of Reactions If a chemical reaction is carried out inside a calorimeter, the heat evolved or absorbed by the reaction can be determined. A calorimeter is an insulated container, and

More information

Calorimetry and Enthalpy. Chapter 5.2

Calorimetry and Enthalpy. Chapter 5.2 Calorimetry and Enthalpy Chapter 5.2 Heat Capacity Specific heat capacity (c) is the quantity of thermal energy required to raise the temperature of 1g of a substance by 1⁰C The units for specific heat

More information

Explorations in Thermodynamics: Calorimetry, Enthalpy & Heats of Reaction

Explorations in Thermodynamics: Calorimetry, Enthalpy & Heats of Reaction Explorations in Thermodynamics: Calorimetry, Enthalpy & Heats of Reaction Dena K. Leggett, Ph.D. and Jon H. Hardesty, Ph.D. Collin County Community College Dept. of Chemistry 1. Introduction: One of the

More information

Experiment 9: Enthalpy of Formation of Magnesium Oxide

Experiment 9: Enthalpy of Formation of Magnesium Oxide 1 Experiment 9: Enthalpy of Formation of Magnesium Oxide Objective: In this experiment, a simple calorimeter will be constructed and calibrated, and Hess law of constant heat summation will be used to

More information

Example: orange juice from frozen concentrate.

Example: orange juice from frozen concentrate. Dilution: a process in which the concentration (molarity) of a solution is lowered. The amount of solute (atoms, moles, grams, etc.) remains the same, but the volume is increased by adding more solvent.

More information

Calorimetry: Determining the Heat of Fusion of Ice and the Heat of Vaporization of Liquid Nitrogen - Chemistry I Acc

Calorimetry: Determining the Heat of Fusion of Ice and the Heat of Vaporization of Liquid Nitrogen - Chemistry I Acc Calorimetry: Determining the Heat of Fusion of Ice and the Heat of Vaporization of Liquid Nitrogen - Chemistry I Acc O B J E C T I V E 1. Using a simple calorimeter, Determine the heat of fusion of ice

More information

Bomb Calorimetry. Example 4. Energy and Enthalpy

Bomb Calorimetry. Example 4. Energy and Enthalpy Bomb Calorimetry constant volume often used for combustion reactions heat released by reaction is absorbed by calorimeter contents need heat capacity of calorimeter q cal = q rxn = q bomb + q water Example

More information

Prelab attached (p 8-9) (g)! MgO (s) + heat (1)

Prelab attached (p 8-9) (g)! MgO (s) + heat (1) CHEM 151 ENTHALPY OF FORMATION OF MgO FALL 2008 Fill-in Prelab attached (p 8-9) Stamp Here Name Partner Lecture instructor Date INTRODUCTION Chemical reactions either produce heat as they proceed (exothermic)

More information

Chapter 5. Thermochemistry

Chapter 5. Thermochemistry Chapter 5. Thermochemistry THERMODYNAMICS - study of energy and its transformations Thermochemistry - study of energy changes associated with chemical reactions Energy - capacity to do work or to transfer

More information

Calorimetry Experiments

Calorimetry Experiments Calorimetry Experiments Pre-Lab: Today s laboratory period will include a variety of activities designed to re-familiarize you with safe practices for chemistry laboratory, the space and equipment you

More information

Science 20. Unit A: Chemical Change. Assignment Booklet A1

Science 20. Unit A: Chemical Change. Assignment Booklet A1 Science 20 Unit A: Chemical Change Assignment Booklet A FOR TEACHER S USE ONLY Summary Teacher s Comments Chapter Assignment Total Possible Marks 79 Your Mark Science 20 Unit A: Chemical Change Assignment

More information

Experiment 7 Energy Accompanying Reactions. Objectives

Experiment 7 Energy Accompanying Reactions. Objectives Experiment 7 Energy Accompanying Reactions Objectives 1. To observe the techniques involved to remove water from a hydrated salt, copper (II) sulphate pentahydrate, CuSO 4 5H 2 O, quantitatively. 2. To

More information

Entropy & Enthalpy Changes A Lab Investigation

Entropy & Enthalpy Changes A Lab Investigation Entropy & Enthalpy Changes A Lab Investigation Summary In this investigation, students will explore basic thermodynamic concepts, including spontaneity, entropy, and enthalpy through a series of guided

More information

THERMOCHEMISTRY & DEFINITIONS

THERMOCHEMISTRY & DEFINITIONS THERMOCHEMISTRY & DEFINITIONS Thermochemistry is the study of the study of relationships between chemistry and energy. All chemical changes and many physical changes involve exchange of energy with the

More information

Chapter 5 Energy Relationships in Chemistry: Thermochemistry

Chapter 5 Energy Relationships in Chemistry: Thermochemistry Chapter 5 Energy Relationships in Chemistry: Thermochemistry In order to study thermochemical changes, we first have to define (a) system that specify part of the universe of interest to us. (b) surrounding

More information

Absorption of Heat. Internal energy is the appropriate energy variable to use at constant volume

Absorption of Heat. Internal energy is the appropriate energy variable to use at constant volume 6 Absorption of Heat According to the First Law, E = q + w = q - P V, assuming P-V work is the only kind that can occur. Therefore, E = q V. The subscript means that the process occurs at constant volume.

More information

Determining the Effectiveness of Container Lids on Heat Absorption: Measuring Heat of Reaction for NaOH(aq) and HCl(aq)

Determining the Effectiveness of Container Lids on Heat Absorption: Measuring Heat of Reaction for NaOH(aq) and HCl(aq) SCHOLARS DAY REVIEW 27 SCHOLARS DAY REVIEW VOLUME 2 Determining the Effectiveness of Container Lids on Heat Absorption: Measuring Heat of Reaction for NaOH(aq) and HCl(aq) Christine L. Burton Faculty Sponsor:

More information

CHEMISTRY. Ionic Bonding

CHEMISTRY. Ionic Bonding CHEMISTRY Ionic Bonding 1 Ionic Bonding Ionic Bonds: Give and take! Ions and Ionic Bonds Atoms with five, six, or seven valence electrons usually become more stable when this number increases to eight.

More information

Solution Stoichiometry Quantitative Preparation of Aqueous Solutions

Solution Stoichiometry Quantitative Preparation of Aqueous Solutions Solution Stoichiometry Quantitative Preparation of Aqueous Solutions Introduction Page 1 of 11 In this week s lab, you and your lab partner will apply your prelab calculations to the preparation of aqueous

More information

CHEMISTRY STANDARDS BASED RUBRIC ATOMIC STRUCTURE AND BONDING

CHEMISTRY STANDARDS BASED RUBRIC ATOMIC STRUCTURE AND BONDING CHEMISTRY STANDARDS BASED RUBRIC ATOMIC STRUCTURE AND BONDING Essential Standard: STUDENTS WILL UNDERSTAND THAT THE PROPERTIES OF MATTER AND THEIR INTERACTIONS ARE A CONSEQUENCE OF THE STRUCTURE OF MATTER,

More information

Additivity of Heats of Reaction: Hess s Law

Additivity of Heats of Reaction: Hess s Law Additivity of Heats of Reaction: Hess s Law Computer 18 In this experiment, you will use a Styrofoam-cup calorimeter to measure the heat released by three reactions. One of the reactions is the same as

More information

Thermochemical equations allow stoichiometric calculations.

Thermochemical equations allow stoichiometric calculations. CHEM 1105 THERMOCHEMISTRY 1. Change in Enthalpy ( H) Heat is evolved or absorbed in all chemical reactions. Exothermic reaction: heat evolved - heat flows from reaction mixture to surroundings; products

More information

Lab Session 9, Experiment 8: Calorimetry, Heat of Reaction

Lab Session 9, Experiment 8: Calorimetry, Heat of Reaction Lab Session 9, Experiment 8: Calorimetry, Heat of Reaction Specific heat is an intensive property of a single phase (solid, liquid or gas) sample that describes how the temperature of the sample changes

More information

Chemistry 151 Final Exam

Chemistry 151 Final Exam Chemistry 151 Final Exam Name: SSN: Exam Rules & Guidelines Show your work. No credit will be given for an answer unless your work is shown. Indicate your answer with a box or a circle. All paperwork must

More information

The Mole Concept. The Mole. Masses of molecules

The Mole Concept. The Mole. Masses of molecules The Mole Concept Ron Robertson r2 c:\files\courses\1110-20\2010 final slides for web\mole concept.docx The Mole The mole is a unit of measurement equal to 6.022 x 10 23 things (to 4 sf) just like there

More information

WATER, ph, ACIDS, BASES, AND BUFFERS

WATER, ph, ACIDS, BASES, AND BUFFERS COURSE READINESS ASSESSMENT FOR PHYSIOLOGY WATER, ph, ACIDS, BASES, AND BUFFERS Sections in this module I. Water is a polar molecule II. Properties of water III. ph IV. Acids and bases V. Buffers I. Water

More information

Chapter Six. Energy Relationships in Chemical Reactions

Chapter Six. Energy Relationships in Chemical Reactions Chapter Six Energy Relationships in Chemical Reactions 1 Energy (U): Capacity to Do Work Radiant energy Energy from the sun Nuclear energy Energy stored in the nucleus of an atom Thermal energy Energy

More information

1. 4 Which particle has two neutrons? 1.

1. 4 Which particle has two neutrons? 1. 1. 4 Which particle has two neutrons? 1. 2. 3. 4. 2. 1 Which electron configuration represents an atom of magnesium in an excited state? 1. 2 7 3 3. 2 8 2 2. 2 7 6 4. 2 8 5 3. 2 Which conclusion was drawn

More information

EXPERIMENT 12 A SOLUBILITY PRODUCT CONSTANT

EXPERIMENT 12 A SOLUBILITY PRODUCT CONSTANT PURPOSE: 1. To determine experimentally the molar solubility of potassium acid tartrate in water and in a solution of potassium nitrate. 2. To examine the effect of a common ion on the solubility of slightly

More information

Thermochemistry I: Endothermic & Exothermic Reactions

Thermochemistry I: Endothermic & Exothermic Reactions THERMOCHEMISTRY I 77 Thermochemistry I: Endothermic & Exothermic Reactions OBJECTIVES: Learn elementary concepts of calorimetry and thermochemistry Practice techniques of careful temperature, mass, and

More information

EXPERIMENT 9. Thermochemistry: Hess Law and the Heat of Formation of MgO

EXPERIMENT 9. Thermochemistry: Hess Law and the Heat of Formation of MgO Outcomes EXPERIMENT 9 Thermochemistry: Hess Law and the Heat of Formation of MgO After completing this experiment, the student should be able to: 1. Differentiate between exothermic and endothermic reactions.

More information

It can be hypothesized that as the number of Carbon atoms in an alcohol increases; the enthalpy of combustion will also become more negative.

It can be hypothesized that as the number of Carbon atoms in an alcohol increases; the enthalpy of combustion will also become more negative. Chemistry Lab Report Aim: The combustion of organic compounds produces large quantities of energy. These compounds range from that of alkanes, to alkenes to even alcohols. Ethanol is a commonly used fuel

More information

Freezing Point Depression: Why Don t Oceans Freeze? Teacher Advanced Version

Freezing Point Depression: Why Don t Oceans Freeze? Teacher Advanced Version Freezing Point Depression: Why Don t Oceans Freeze? Teacher Advanced Version Freezing point depression describes the process where the temperature at which a liquid freezes is lowered by adding another

More information

Notes: Formula Mass and Percent Composition

Notes: Formula Mass and Percent Composition Notes: Formula Mass and Percent Composition Formula mass - the mass of one mole of a compound, atom or ion. -also called: gram formula mass, molecular mass, gram molecular mass, formula weight, gram formula

More information

More on ions (Chapters 2.1 and )

More on ions (Chapters 2.1 and ) More on ions (Chapters 2.1 and 3.5 3.7) Ion: an atom or molecule that has a net electrical charge. Examples: Na + (sodium ion), Cl - (chloride), NH 4 + (ammonium). Anion: a negative ion, formed when electrons

More information

AP* Chemistry THERMOCHEMISTRY

AP* Chemistry THERMOCHEMISTRY AP* Chemistry THERMOCHEMISTRY Terms for you to learn that will make this unit understandable: Energy (E) the ability to do work or produce heat ; the sum of all potential and kinetic energy in a system

More information

Goals Pearson Education, Inc.

Goals Pearson Education, Inc. Goals 1. What is an ion, what is an ionic bond, and what are the general characteristics of ionic compounds? Be able to describe ions and ionic bonds, and give the general properties of compounds that

More information

ENERGY. Thermochemistry. Heat. Temperature & Heat. Thermometers & Temperature. Temperature & Heat. Energy is the capacity to do work.

ENERGY. Thermochemistry. Heat. Temperature & Heat. Thermometers & Temperature. Temperature & Heat. Energy is the capacity to do work. ENERGY Thermochemistry Energy is the capacity to do work. Chapter 6 Kinetic Energy thermal, mechanical, electrical, sound Potential Energy chemical, gravitational, electrostatic Heat Heat, or thermal energy,

More information

CSUS Department of Chemistry Experiment 4 Chem.1A

CSUS Department of Chemistry Experiment 4 Chem.1A Name: Section: Experiment 4: Synthesis of Alum Pre-laboratory Assignment (Read through the experiment before starting!) 1. a) What are the strong acid and strong base used in this synthesis? b) What should

More information

7. 2. KOH (you need an acid or a base, this is a base) 8. 1. 76. All gold atoms have 79 protons and electrons, this is a +3 cation.

7. 2. KOH (you need an acid or a base, this is a base) 8. 1. 76. All gold atoms have 79 protons and electrons, this is a +3 cation. IB/SL Chemistry Name ANSWERS Test; Past Chemistry Regents Exams Most Frequently Missed Questions 1. 1. A HIGH PROBABLITY OF FINDING AN ELECTRON 2. 3. +8 (every atom of oxygen in the universe) 3. 2. LOW

More information

3A Energy. What is chemical energy?

3A Energy. What is chemical energy? 3A Energy What is chemical energy? Chemical energy is a form of potential energy which is stored in chemical bonds. Chemical bonds are the attractive forces that bind atoms together. As a reaction takes

More information

Chem101: General Chemistry Lecture 9 Acids and Bases

Chem101: General Chemistry Lecture 9 Acids and Bases : General Chemistry Lecture 9 Acids and Bases I. Introduction A. In chemistry, and particularly biochemistry, water is the most common solvent 1. In studying acids and bases we are going to see that water

More information

Chapter 5 Thermochemistry

Chapter 5 Thermochemistry Chapter 5 Thermochemistry 1. The ΔE of a system that releases 14.4 J of heat and does 4.8 J of work on the surroundings is J. (a). 19.2 J (b). 14.4 J (c). 4.8 J (d). - 19.2 J Explanation: The ΔE can be

More information

1. Thermite reaction 2. Enthalpy of reaction, H 3. Heating/cooling curves and changes in state 4. More thermite thermodynamics

1. Thermite reaction 2. Enthalpy of reaction, H 3. Heating/cooling curves and changes in state 4. More thermite thermodynamics Chem 105 Fri 10-23-09 1. Thermite reaction 2. Enthalpy of reaction, H 3. Heating/cooling curves and changes in state 4. More thermite thermodynamics 10/23/2009 1 Please PICK UP your graded EXAM in front.

More information

By adding Equations 1, 2, and 3, the Overall Equation is obtained. Summation of their enthalpies gives the enthalpy of formation for MgO.

By adding Equations 1, 2, and 3, the Overall Equation is obtained. Summation of their enthalpies gives the enthalpy of formation for MgO. The standard enthalpy of formation of a compound, Hf o, is the heat change accompanying the formation of one mole of compound from the elements at standard state. The standard state of a substance is the

More information

How many ml of 0.250M potassium permangenate are needed to react with 3.36 g of iron(ii) sulfate?

How many ml of 0.250M potassium permangenate are needed to react with 3.36 g of iron(ii) sulfate? How many ml of 0.250M potassium permangenate are needed to react with 3.36 g of iron(ii) sulfate? 1 - Change the mass of iron(ii) sulfate to moles using the formula weight.of iron(ii) sulfate 2 - Change

More information

Chemistry B11 Chapter 4 Chemical reactions

Chemistry B11 Chapter 4 Chemical reactions Chemistry B11 Chapter 4 Chemical reactions Chemical reactions are classified into five groups: A + B AB Synthesis reactions (Combination) H + O H O AB A + B Decomposition reactions (Analysis) NaCl Na +Cl

More information

UNIT 1 THERMOCHEMISTRY

UNIT 1 THERMOCHEMISTRY UNIT 1 THERMOCHEMISTRY THERMOCHEMISTRY LEARNING OUTCOMES Students will be expected to: THERMOCHEMISTRY STSE analyse why scientific and technological activities take place in a variety individual and group

More information

Simple Experiments in Thermochemistry

Simple Experiments in Thermochemistry Simple Experiments in Thermochemistry Purpose: To demonstrate the law of conservation of energy and propose a method for making a chemical heat pack using the heats of solution of sodium bicarbonate and

More information

Endothermic and Exothermic Processes

Endothermic and Exothermic Processes Endothermic and Exothermic Processes Teacher Preparation Purpose Students will measure temperature changes that occur as chemical compounds dissolve in water. They will collect temperature data for three

More information

Determination of an Empirical Formula and % Composition

Determination of an Empirical Formula and % Composition Chem 110 Lab Clark College Determination of an Empirical Formula and % Composition Percent composition will be discussed in your text, lecture and in lab. This concept is often used to determine how many

More information

Chemistry Final Exam Review

Chemistry Final Exam Review Name: Date: Block: Chemistry Final Exam Review 2012-2013 Unit 1: Measurement, Numbers, Scientific Notation, Conversions, Dimensional Analysis 1. Write 0.000008732 in scientific notation 8.732x10-6 2. Write

More information

The Relationships Between. Internal Energy, Heat, Enthalpy, and Calorimetry

The Relationships Between. Internal Energy, Heat, Enthalpy, and Calorimetry The Relationships Between Internal Energy, Heat, Enthalpy, and Calorimetry Recap of Last Class Last class, we began our discussion about energy changes that accompany chemical reactions Chapter 5 discusses:

More information

SOLUBILITY OF A SALT IN WATER AT VARIOUS TEMPERATURES LAB

SOLUBILITY OF A SALT IN WATER AT VARIOUS TEMPERATURES LAB SOLUBILITY OF A SALT IN WATER AT VARIOUS TEMPERATURES LAB Purpose: Most ionic compounds are considered by chemists to be salts and many of these are water soluble. In this lab, you will determine the solubility,

More information

Calorimetry Lab - Specific Heat Capacity

Calorimetry Lab - Specific Heat Capacity Introduction Calorimetry Lab - Specific Heat Capacity Experience tells us that if a hot piece of metal is added to water, the temperature of the water will rise. If several different metals having the

More information

Determining the Identity of an Unknown Weak Acid

Determining the Identity of an Unknown Weak Acid Purpose The purpose of this experiment is to observe and measure a weak acid neutralization and determine the identity of an unknown acid by titration. Introduction The purpose of this exercise is to identify

More information

Water Lab. Objective: To distill samples of water that contains volatile and nonvolatile components.

Water Lab. Objective: To distill samples of water that contains volatile and nonvolatile components. Water Lab I. Distillation Hypothesis: Water can be purified by distillation. Objective: To distill samples of water that contains volatile and nonvolatile components. Materials and Equipment: Sodium chloride,

More information

The energy level diagram for this reaction is shown below.

The energy level diagram for this reaction is shown below. Q. Methanol can be made when methane reacts with oxygen. (a) The energy level diagram for this reaction is shown below. (i) What is the energy change represented by A? () (ii) Use the energy level diagram

More information

Chapter 6 Quantities in Chemical Reactions

Chapter 6 Quantities in Chemical Reactions Chapter 6 Quantities in Chemical Reactions The Meaning of a Balanced Chemical Equation Mole-Mole Conversions Mass-Mass Conversions Limiting Reactants Percent Yield Energy Changes Copyright The McGraw-Hill

More information

Chemistry Guide

Chemistry Guide 551534 - Chemistry Guide 1- Contents Question Item Objective Type Skill 1 0102 M03.02.04 Multiple-choice answer Mastery of Problem Solving 2 0099 M03.03.02 Multiple-choice answer Mastery of Concepts 3

More information

Experiment 25: Calorimetry

Experiment 25: Calorimetry Aaron Bunch CHEM 111 Morning Lab 27 October 2014 Experiment 25: Calorimetry Conclusion: The unknown metal #14 has a specific heat of 0.36 J/g C; the heat of neutralization of HCl and NaOH is -53.0 kj/mol

More information