DETERMINING AND USING H
|
|
- Anthony Norris
- 7 years ago
- Views:
Transcription
1 DETERMINING AND USING H 1 INTRODUCTION CHANGES IN CHEMISTRY Chemistry is the science that studies matter and the changes it undergoes. Changes are divided into two categories: physical and chemical. During a physical change, some physical property of the substance changes, although the identity of the substance remains the same. For example, the melting of ice to make liquid water is a physical change: H 2 O(s) H 2 O(l) However, when a piece of sodium metal is placed in water, a chemical change occurs. The element sodium reacts with water to make the compound sodium hydroxide and the element hydrogen: 2 Na(s) + 2 H 2 O(l) 2 NaOH(aq) + H 2 (g) When the process is complete, the original substances no longer exist. New substances, with new properties have been made. INTERNAL ENERGY Every change, whether physical or chemical, is accompanied by a change in the internal energy (E) of the system. In the case of melting ice, the molecules absorb heat from the surroundings. Their internal energy increases as they liquefy. In the reaction between sodium and water, the internal energy of these two substances decreases as sodium hydroxide and hydrogen are produced. The change in internal energy is symbolized by E. The first law of thermodynamics defines the change in internal energy as E = q + w, where q refers to the heat exchanged between reaction system and surroundings, and w refers to the work done by or on the reaction system. A sign convention here is important. With the reaction system as the point of reference, positive signs are used for q and w if the system absorbs heat or is worked upon. Negative signs are used if the reaction system loses heat or does work. MEASURING E AND H To measure E values, a sealed bomb calorimeter is required. In such a calorimeter, no work can be done. Therefore, w = 0 and E = q. This q is often labeled q v since the reaction is carried out at constant volume. In lab, simple calorimeters are usually used. They are open to the atmosphere. The reaction system can exchange both heat and work with the surroundings. However, the work component is difficult to measure. Furthermore, it is usually small compared to the heat component. For that reason, we ignore the work component and measure just the heat component. Since the atmospheric pressure is essentially constant for the duration of the reaction, we label the heat as q P. This value, q p, is not equal to E (since E = q + w, and w is not 0 in this case). The q P term has been named H and symbolizes the change in enthalpy. Enthalpy is similar to, but not the same as, internal energy. It is often called the "heat content" of a substance.
2 2 MEASURING HEAT Heat is an energy transfer that results because of a temperature difference between two things. Since it is a form of energy, heat has energy units, either Joules (J) or calories (cal). Heat flows from hot to cold. The energy transfer stops when the objects have reached the same temperature. The amount of heat lost equals the amount of heat gained. To calculate heat, we use the q equation: q = (m)(sp.ht.)( T) where m = mass, sp.ht. = specific heat (a unique constant for each substance) and T = change in temperature, defined as T FINAL T INITIAL. If T FINAL is higher than T INITIAL, then T is positive and q is positive. An object with a positive q has gained heat during the energy transfer. If T FINAL is lower than T INITIAL for an object, then its T is negative, causing its q to be negative. A negative q value for an object signifies that it has lost heat during the energy transfer. Heat exchanges between system and surroundings are measured in special containers called calorimeters. They may be as sophisticated as a bomb calorimeter, or simple as a Styrofoam coffee cup or thermos. The system is whatever substances undergo the change. The surroundings are all the other contents of the container as well as the container itself. If the system loses heat, all of it goes to the surroundings. Therefore, the ability of the container to absorb heat must first be established. Often a calorimeter constant, C CAL is determined. For the calorimeters used in this experiment, C CAL is equal to 89 J/ o C. The value of C CAL equals the m(sp.ht.) portion of the heat equation. Therefore, the q equation can be written as follows, when it is applied to a calorimeter: q cal = C cal T cal H INFORMATION AND EQUATIONS Once H data has been determined for a reaction, it is often written at the end of the balanced equation. Its value corresponds to the balanced equation when interpreted in terms of moles. For example: H 2 O(s) H 2 O(l) H = +6.0 kj 2 Na(s) + 2 H 2 O(l) 2 NaOH(aq) + H 2 (g) H = 367 kj In the first case, when one mole of solid water (ice) undergoes melting, 6.0 kj of heat are absorbed by the water molecules. In the second case, when two moles of solid sodium react with two moles of liquid water, two moles of aqueous sodium hydroxide and one mole of gaseous hydrogen are produced, and 367 kj of heat are given off to the surroundings. Note that there is no such thing as positive or negative heat. The positive and negative signs simply signify the direction of heat flow, into or out of the system. HESS'S LAW Sometimes a chemical product is made in one step; in other cases, several steps may be required to make the desired product. For example, substance "E" can be made as follows: (Step 1) A + B C (Step 2) C + D E The net reaction can be found by adding the two steps: (Net) A + B + D E
3 3 The C's in steps 1 and 2 cancel. The value of H for the net reaction can be found by adding the H values for each step. If the values are: (Step 1) H = kj (Step 2) H = 300. kj then the value of H for the net reaction is 200. kj. PURPOSE OF THIS LAB In this lab, we will determine the value of H for two processes. One is a chemical change, the other is a physical change. Then, we will use this lab data as well as additional data for two other reactions to determine H for a third reaction by means of Hess's law. PROCEDURE A. Determination of H for the reaction HCl(aq) + NH 3 (aq) NH 4 Cl(aq) 1. Measure out 50.0 ml of 2.00 M NH 3. Pour it into the calorimeter. Measure and record the temperature of the solution. 2. Measure out 50.0 ml of 2.00 M HCl in a clean, dry graduated cylinder. Measure and record its temperature. NOTE: The temperatures of the two solutions are probably almost the same. If they are not, use the average of the two as the initial temperature of the chemical system. 3. Add the HCl solution to the NH 3 solution in the calorimeter. Stir, and record the highest temperature reached. 4. Pour the contents of the calorimeter down the drain. Dry the calorimeter with a paper towel. When finished, dry the calorimeter before beginning part B. B. Determination of H for the process NH 4 Cl(s) NH 4 Cl(aq) 5. On the balance, weigh out a gram sample of solid ammonium chloride, NH 4 Cl. Record the actual mass you use. 6. Place 50.0 ml of room temperature water in the calorimeter. Measure and record its temperature. 7. Add the NH 4 Cl to the water. Stir and record the lowest temperature reached. 8. Pour the calorimeter contents down the drain.
4 4 DETERMINING AND USING H Data Sheet Name Partner Be sure to use the correct number of significant figures for the volumes and temperatures you record below! A. Determination of H for the reaction HCl(aq) + NH 3 (aq) NH 4 Cl(aq) BEFORE MIXING volume of 2.00 M NH 3 temperature of 2.00 M NH 3 volume of 2.00 M HCl temperature of 2.00 M HCl average temperature (T INITIAL for solution and calorimeter) AFTER MIXING temperature of mixture (T FINAL for solution) temperature of calorimeter (T FINAL for calorimeter) B. Determination of H for the process NH 4 Cl(s) NH 4 Cl(aq) BEFORE MIXING Volume of H 2 O mass of NH 4 Cl(s) temperature of water (T INITIAL for solution) temperature of calorimeter (T INITIAL for calorimeter) AFTER MIXING temperature of mixture (T FINAL for solution) temperature of calorimeter (T FINAL for calorimeter) ml ml ml g
5 DETERMINING AND USING H Calculations Sheets Name Partner 5 Show your work clearly, in the space provided, for each of the following calculations. Enter the answer on the line provided. The specific heat of water is J/gC o. Assume this is also the specific heat of the dilute aqueous solutions we use here. The calorimeter constant you will use, C cal, is 89 J/ o C Also, watch signs (+ or ) carefully and think about their meanings. A. Determination of H for the reaction HCl(aq) + NH 3 (aq) NH 4 Cl(aq) 1. T SOLUTION C o 2. mass of solution g Its density is 1.03 g/ml 3. q for solution J q sol n = (m)(sp.ht.)( T) 4. q for calorimeter J q cal = C CAL x T CAL 5. q for reactant system J The amount of heat gained by the solution and the calorimeter equals the amount of heat lost by the reactant system. Watch your signs! 6. moles of NH 3 used mol Remember, you know the volume and the molarity. 7. moles of HCl used mol 8. Is there a limiting reactant? Explain:
6 6 9. q for one mole of limiting reactant J/mol 10. H (HINT: Look at units to do this conversion.) kj/mol B. Determination of H for the process NH 4 Cl(s) NH 4 Cl(aq) 11. T SOLUTION C o 12. mass of solution (NH 4 Cl and water) g 13. q for the solution J q sol n = (m)(sp.ht.)( T) 14. q for the calorimeter J q cal = C CAL x T CAL 15. q for the reactant system J The heat lost by the solution and calorimeter has been absorbed by the reactant system. 16. moles of NH 4 Cl used mol 17. q for one mole of NH 4 Cl J/mol 18. H kj/mol
7 7 19. Application of Hess's law to the lab data You have now determined the value of H for a chemical change and a physical change involving ammonium chloride. Use your lab data as well as the data given below to determine the value of H for the decomposition reaction: NH 4 Cl(s) NH 3 (g) + HCl(g) Consider the following as you make your determination. (1) HCl(aq) + NH 3 (aq) NH 4 Cl(aq) H = kj (2) NH 4 Cl(s) NH 4 Cl(aq) H = kj (3) NH 3 (g) NH 3 (aq) H = 34.6 kj (4) HCl(g) HCl(aq) H = 75.1 kj Show all manipulated equations as well as your calculations here.
8 8 DETERMINING AND USING H Pre-Lab Assignment Name Section 1. How much heat is lost when 75.0 g. copper (sp. ht J/g o C) at 57.2 o C are cooled to 11.7 o C? 2. Using the data from the table in Appendix II B in your textbook, or some other reference source, determine the value for the enthalpy change (ΔH) for reaction (1) and reaction (2) on page 7 of this lab. (Refer to section 6.9 in your textbook if necessary). Make sure that you use the value for the correct form of the substance (For instance, ΔHf HCl(aq) is different than ΔHf HCl (g) ). Last revised 8/21/2016 DN
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 informationHEAT 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 informationTransfer 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 informationDETERMINING 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 informationPREPARATION FOR CHEMISTRY LAB: COMBUSTION
1 Name: Lab Instructor: PREPARATION FOR CHEMISTRY LAB: COMBUSTION 1. What is a hydrocarbon? 2. What products form in the complete combustion of a hydrocarbon? 3. Combustion is an exothermic reaction. What
More informationThermochemical 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 informationENTHALPY CHANGES FOR A CHEMICAL REACTION scaling a rxn up or down (proportionality) quantity 1 from rxn heat 1 from Δ r H. = 32.
CHEMISTRY 103 Help Sheet #10 Chapter 4 (Part II); Sections 4.6-4.10 Do the topics appropriate for your lecture Prepared by Dr. Tony Jacob http://www.chem.wisc.edu/areas/clc (Resource page) Nuggets: Enthalpy
More informationUNIT 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 informationHeat 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 informationBomb 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 informationthermometer as simple as a styrofoam cup and a thermometer. In a calorimeter the reactants are placed into the
Thermochemistry Readin assinment: Chan, Chemistry 10 th edition, pp. 249-258. Goals We will become familiar with the principles of calorimetry in order to determine the heats of reaction for endothermic
More informationExp 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 information87 16 70 20 58 24 44 32 35 40 29 48 (a) graph Y versus X (b) graph Y versus 1/X
HOMEWORK 5A Barometer; Boyle s Law 1. The pressure of the first two gases below is determined with a manometer that is filled with mercury (density = 13.6 g/ml). The pressure of the last two gases below
More informationThermochemistry 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 informationEnergy and Chemical Reactions. Characterizing Energy:
Energy and Chemical Reactions Energy: Critical for virtually all aspects of chemistry Defined as: We focus on energy transfer. We observe energy changes in: Heat Transfer: How much energy can a material
More informationFORMA is EXAM I, VERSION 1 (v1) Name
FORMA is EXAM I, VERSION 1 (v1) Name 1. DO NOT TURN THIS PAGE UNTIL DIRECTED TO DO SO. 2. These tests are machine graded; therefore, be sure to use a No. 1 or 2 pencil for marking the answer sheets. 3.
More informationMr. Bracken. Multiple Choice Review: Thermochemistry
Mr. Bracken AP Chemistry Name Period Multiple Choice Review: Thermochemistry 1. If this has a negative value for a process, then the process occurs spontaneously. 2. This is a measure of how the disorder
More informationIB Chemistry. DP Chemistry Review
DP Chemistry Review Topic 1: Quantitative chemistry 1.1 The mole concept and Avogadro s constant Assessment statement Apply the mole concept to substances. Determine the number of particles and the amount
More informationThermochemistry. r2 d:\files\courses\1110-20\99heat&thermorans.doc. Ron Robertson
Thermochemistry r2 d:\files\courses\1110-20\99heat&thermorans.doc Ron Robertson I. What is Energy? A. Energy is a property of matter that allows work to be done B. Potential and Kinetic Potential energy
More informationThermodynamics. Thermodynamics 1
Thermodynamics 1 Thermodynamics Some Important Topics First Law of Thermodynamics Internal Energy U ( or E) Enthalpy H Second Law of Thermodynamics Entropy S Third law of Thermodynamics Absolute Entropy
More informationEXPERIMENT 7 Reaction Stoichiometry and Percent Yield
EXPERIMENT 7 Reaction Stoichiometry and Percent Yield INTRODUCTION Stoichiometry calculations are about calculating the amounts of substances that react and form in a chemical reaction. The word stoichiometry
More informationChemistry: Chemical Equations
Chemistry: Chemical Equations Write a balanced chemical equation for each word equation. Include the phase of each substance in the equation. Classify the reaction as synthesis, decomposition, single replacement,
More informationDetermination of a Chemical Formula
1 Determination of a Chemical Formula Introduction Molar Ratios Elements combine in fixed ratios to form compounds. For example, consider the compound TiCl 4 (titanium chloride). Each molecule of TiCl
More informationChemistry 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 informationCHEM 105 HOUR EXAM III 28-OCT-99. = -163 kj/mole determine H f 0 for Ni(CO) 4 (g) = -260 kj/mole determine H f 0 for Cr(CO) 6 (g)
CHEM 15 HOUR EXAM III 28-OCT-99 NAME (please print) 1. a. given: Ni (s) + 4 CO (g) = Ni(CO) 4 (g) H Rxn = -163 k/mole determine H f for Ni(CO) 4 (g) b. given: Cr (s) + 6 CO (g) = Cr(CO) 6 (g) H Rxn = -26
More informationFreezing 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 informationProblem Solving. Stoichiometry of Gases
Skills Worksheet Problem Solving Stoichiometry of Gases Now that you have worked with relationships among moles, mass, and volumes of gases, you can easily put these to work in stoichiometry calculations.
More informationStandard Free Energies of Formation at 298 K. Average Bond Dissociation Energies at 298 K
1 Thermodynamics There always seems to be at least one free response question that involves thermodynamics. These types of question also show up in the multiple choice questions. G, S, and H. Know what
More informationLiquid phase. Balance equation Moles A Stoic. coefficient. Aqueous phase
STOICHIOMETRY Objective The purpose of this exercise is to give you some practice on some Stoichiometry calculations. Discussion The molecular mass of a compound is the sum of the atomic masses of all
More informationThermodynamics Worksheet I also highly recommend Worksheets 13 and 14 in the Lab Manual
Thermodynamics Worksheet I also highly recommend Worksheets 13 and 14 in the Lab Manual 1. Predict the sign of entropy change in the following processes a) The process of carbonating water to make a soda
More informationChemical Calculations: Formula Masses, Moles, and Chemical Equations
Chemical Calculations: Formula Masses, Moles, and Chemical Equations Atomic Mass & Formula Mass Recall from Chapter Three that the average mass of an atom of a given element can be found on the periodic
More informationInstructions Answer all questions in the spaces provided. Do all rough work in this book. Cross through any work you do not want to be marked.
GCSE CHEMISTRY Higher Tier Chemistry 1H H Specimen 2018 Time allowed: 1 hour 45 minutes Materials For this paper you must have: a ruler a calculator the periodic table (enclosed). Instructions Answer all
More informationEXPERIMENT 12: Empirical Formula of a Compound
EXPERIMENT 12: Empirical Formula of a Compound INTRODUCTION Chemical formulas indicate the composition of compounds. A formula that gives only the simplest ratio of the relative number of atoms in a compound
More informationTest 5 Review questions. 1. As ice cools from 273 K to 263 K, the average kinetic energy of its molecules will
Name: Thursday, December 13, 2007 Test 5 Review questions 1. As ice cools from 273 K to 263 K, the average kinetic energy of its molecules will 1. decrease 2. increase 3. remain the same 2. The graph below
More informationChapter 18 Homework Answers
Chapter 18 Homework Answers 18.22. 18.24. 18.26. a. Since G RT lnk, as long as the temperature remains constant, the value of G also remains constant. b. In this case, G G + RT lnq. Since the reaction
More informationBalance the following equation: KClO 3 + C 12 H 22 O 11 KCl + CO 2 + H 2 O
Balance the following equation: KClO 3 + C 12 H 22 O 11 KCl + CO 2 + H 2 O Ans: 8 KClO 3 + C 12 H 22 O 11 8 KCl + 12 CO 2 + 11 H 2 O 3.2 Chemical Symbols at Different levels Chemical symbols represent
More informationChemistry 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 informationStoichiometry Limiting Reagent Laboratory. Chemistry 118 Laboratory University of Massachusetts, Boston
Chemistry 118 Laboratory University of Massachusetts, Boston STOICHIOMETRY - LIMITING REAGENT --------------------------------------------------------------------------------------------------------------------------------------------
More informationEnthalpy of Reaction and Calorimetry worksheet
Enthalpy of Reaction and Calorimetry worksheet 1. Calcium carbonate decomposes at high temperature to form carbon dioxide and calcium oxide, calculate the enthalpy of reaction. CaCO 3 CO 2 + CaO 2. Carbon
More informationChapter 5, Calculations and the Chemical Equation
1. How many iron atoms are present in one mole of iron? Ans. 6.02 1023 atoms 2. How many grams of sulfur are found in 0.150 mol of sulfur? [Use atomic weight: S, 32.06 amu] Ans. 4.81 g 3. How many moles
More informationThermochemistry: 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 informationstoichiometry = the numerical relationships between chemical amounts in a reaction.
1 REACTIONS AND YIELD ANSWERS stoichiometry = the numerical relationships between chemical amounts in a reaction. 2C 8 H 18 (l) + 25O 2 16CO 2 (g) + 18H 2 O(g) From the equation, 16 moles of CO 2 (a greenhouse
More informationThe Empirical Formula of a Compound
The Empirical Formula of a Compound Lab #5 Introduction A look at the mass relationships in chemistry reveals little order or sense. The ratio of the masses of the elements in a compound, while constant,
More information5. Which temperature is equal to +20 K? 1) 253ºC 2) 293ºC 3) 253 C 4) 293 C
1. The average kinetic energy of water molecules increases when 1) H 2 O(s) changes to H 2 O( ) at 0ºC 3) H 2 O( ) at 10ºC changes to H 2 O( ) at 20ºC 2) H 2 O( ) changes to H 2 O(s) at 0ºC 4) H 2 O( )
More informationHands-On Labs SM-1 Lab Manual
EXPERIMENT 4: Separation of a Mixture of Solids Read the entire experiment and organize time, materials, and work space before beginning. Remember to review the safety sections and wear goggles when appropriate.
More informationUnit 2: Quantities in Chemistry
Mass, Moles, & Molar Mass Relative quantities of isotopes in a natural occurring element (%) E.g. Carbon has 2 isotopes C-12 and C-13. Of Carbon s two isotopes, there is 98.9% C-12 and 11.1% C-13. Find
More informationStoichiometry Limiting Reagent Laboratory. Chemistry 118 Laboratory University of Massachusetts, Boston
Chemistry 118 Laboratory University of Massachusetts, Boston STOICHIOMETRY - LIMITING REAGENT -----------------------------------------------------------------------------------------------------------------------------
More informationRecovery of Elemental Copper from Copper (II) Nitrate
Recovery of Elemental Copper from Copper (II) Nitrate Objectives: Challenge: Students should be able to - recognize evidence(s) of a chemical change - convert word equations into formula equations - perform
More informationChemistry 110 Lecture Unit 5 Chapter 11-GASES
Chemistry 110 Lecture Unit 5 Chapter 11-GASES I. PROPERITIES OF GASES A. Gases have an indefinite shape. B. Gases have a low density C. Gases are very compressible D. Gases exert pressure equally in all
More informationGeneral Chemistry I (FC, 09-10) Lab #3: The Empirical Formula of a Compound. Introduction
General Chemistry I (FC, 09-10) Introduction A look at the mass relationships in chemistry reveals little order or sense. The ratio of the masses of the elements in a compound, while constant, does not
More informationPHYSICAL SEPARATION TECHNIQUES. Introduction
PHYSICAL SEPARATION TECHNIQUES Lab #2 Introduction When two or more substances, that do not react chemically, are blended together, the result is a mixture in which each component retains its individual
More informationTest Review # 9. Chemistry R: Form TR9.13A
Chemistry R: Form TR9.13A TEST 9 REVIEW Name Date Period Test Review # 9 Collision theory. In order for a reaction to occur, particles of the reactant must collide. Not all collisions cause reactions.
More informationTarget Mole Lab. Mole Relationships and the Balanced Equation. For each student group Hydrochloric acid solution, HCl, 3 M, 30 ml
elearning 2009 Introduction Target Mole Lab Mole Relationships and the Balanced Equation Publication No. A common chemical reaction used in chemistry class is zinc and hydrochloric In this lab, students
More informationStates of Matter CHAPTER 10 REVIEW SECTION 1. Name Date Class. Answer the following questions in the space provided.
CHAPTER 10 REVIEW States of Matter SECTION 1 SHORT ANSWER Answer the following questions in the space provided. 1. Identify whether the descriptions below describe an ideal gas or a real gas. ideal gas
More informationName Class Date. Section: Calculating Quantities in Reactions. Complete each statement below by writing the correct term or phrase.
Skills Worksheet Concept Review Section: Calculating Quantities in Reactions Complete each statement below by writing the correct term or phrase. 1. All stoichiometric calculations involving equations
More informationAppendix D. Reaction Stoichiometry D.1 INTRODUCTION
Appendix D Reaction Stoichiometry D.1 INTRODUCTION In Appendix A, the stoichiometry of elements and compounds was presented. There, the relationships among grams, moles and number of atoms and molecules
More informationWorksheet #17. 2. How much heat is released when 143 g of ice is cooled from 14 C to 75 C, if the specific heat capacity of ice is 2.087 J/(g C).
Worksheet #17 Calculating Heat 1. How much heat is needed to bring 12.0 g of water from 28.3 C to 43.87 C, if the specific heat capacity of water is 4.184 /(g? 2. How much heat is released when 143 g of
More informationUnit 5 Practice Test. Name: Class: Date: Multiple Choice Identify the choice that best completes the statement or answers the question.
Name: Class: Date: Unit 5 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1) The internal energy of a system is always increased by. A) adding
More informationSUPPLEMENTARY TOPIC 3 ENERGY AND CHEMICAL REACTIONS
SUPPLEMENTARY TOPIC 3 ENERGY AND CHEMICAL REACTIONS Rearranging atoms. In a chemical reaction, bonds between atoms in one or more molecules (reactants) break and new bonds are formed with other atoms to
More informationIB Chemistry 1 Mole. One atom of C-12 has a mass of 12 amu. One mole of C-12 has a mass of 12 g. Grams we can use more easily.
The Mole Atomic mass units and atoms are not convenient units to work with. The concept of the mole was invented. This was the number of atoms of carbon-12 that were needed to make 12 g of carbon. 1 mole
More informationSEPARATION OF A MIXTURE OF SUBSTANCES LAB
SEPARATION OF A MIXTURE OF SUBSTANCES LAB Purpose: Every chemical has a set of defined physical properties, and when combined they present a unique fingerprint for that chemical. When chemicals are present
More informationCHEMICAL REACTIONS OF COPPER AND PERCENT YIELD KEY
CHEMICAL REACTIONS OF COPPER AND PERCENT YIELD Objective To gain familiarity with basic laboratory procedures, some chemistry of a typical transition element, and the concept of percent yield. Apparatus
More informationExperiment 8 - Double Displacement Reactions
Experiment 8 - Double Displacement Reactions A double displacement reaction involves two ionic compounds that are dissolved in water. In a double displacement reaction, it appears as though the ions are
More informationChemical Reactions in Water Ron Robertson
Chemical Reactions in Water Ron Robertson r2 f:\files\courses\1110-20\2010 possible slides for web\waterchemtrans.doc Properties of Compounds in Water Electrolytes and nonelectrolytes Water soluble compounds
More informationApparatus error for each piece of equipment = 100 x margin of error quantity measured
1) Error Analysis Apparatus Errors (uncertainty) Every time you make a measurement with a piece of apparatus, there is a small margin of error (i.e. uncertainty) in that measurement due to the apparatus
More informationHonors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1. A chemical equation. (C-4.4)
Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1 1. 2. 3. 4. 5. 6. Question What is a symbolic representation of a chemical reaction? What 3 things (values) is a mole of a chemical
More informationThe 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 informationChapter 8 - Chemical Equations and Reactions
Chapter 8 - Chemical Equations and Reactions 8-1 Describing Chemical Reactions I. Introduction A. Reactants 1. Original substances entering into a chemical rxn B. Products 1. The resulting substances from
More information1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams?
Name: Tuesday, May 20, 2008 1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams? 2 5 1. P2O 5 3. P10O4 2. P5O 2 4. P4O10 2. Which substance
More informationChemical Changes. Measuring a Chemical Reaction. Name(s)
Chemical Changes Name(s) In the particle model of matter, individual atoms can be bound tightly to other atoms to form molecules. For example, water molecules are made up of two hydrogen atoms bound to
More informationReview - After School Matter Name: Review - After School Matter Tuesday, April 29, 2008
Name: Review - After School Matter Tuesday, April 29, 2008 1. Figure 1 The graph represents the relationship between temperature and time as heat was added uniformly to a substance starting at a solid
More informationThe first law: transformation of energy into heat and work. Chemical reactions can be used to provide heat and for doing work.
The first law: transformation of energy into heat and work Chemical reactions can be used to provide heat and for doing work. Compare fuel value of different compounds. What drives these reactions to proceed
More informationChapter 4 Practice Quiz
Chapter 4 Practice Quiz 1. Label each box with the appropriate state of matter. A) I: Gas II: Liquid III: Solid B) I: Liquid II: Solid III: Gas C) I: Solid II: Liquid III: Gas D) I: Gas II: Solid III:
More informationName Class Date. In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question.
Assessment Chapter Test A Chapter: States of Matter In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. 1. The kinetic-molecular
More informationEXPERIMENT 10 Chemistry 110. Solutions Part 2 ACIDS, BASES, AND ELECTROLYTES
EXPERIMENT 10 Chemistry 110 Solutions Part 2 ACIDS, BASES, AND ELECTROLYTES PURPOSE: The purpose of this experiment is to determine the properties of solutions of acids, bases and electrolytes. Students
More informationModule 5: Combustion Technology. Lecture 34: Calculation of calorific value of fuels
1 P age Module 5: Combustion Technology Lecture 34: Calculation of calorific value of fuels 2 P age Keywords : Gross calorific value, Net calorific value, enthalpy change, bomb calorimeter 5.3 Calculation
More informationAP Chemistry 2005 Scoring Guidelines Form B
AP Chemistry 2005 Scoring Guidelines Form B The College Board: Connecting Students to College Success The College Board is a not-for-profit membership association whose mission is to connect students to
More informationChemistry Assessment Unit AS 1
Centre Number 71 Candidate Number ADVANCED SUBSIDIARY (AS) General Certificate of Education January 2011 Chemistry Assessment Unit AS 1 assessing Basic Concepts in Physical and Inorganic Chemistry [AC111]
More informationProperties of Acids and Bases
Lab 22 Properties of Acids and Bases TN Standard 4.2: The student will investigate the characteristics of acids and bases. Have you ever brushed your teeth and then drank a glass of orange juice? What
More informationChapter 3. Chemical Reactions and Reaction Stoichiometry. Lecture Presentation. James F. Kirby Quinnipiac University Hamden, CT
Lecture Presentation Chapter 3 Chemical Reactions and Reaction James F. Kirby Quinnipiac University Hamden, CT The study of the mass relationships in chemistry Based on the Law of Conservation of Mass
More information1. Read P. 368-375, P. 382-387 & P. 429-436; P. 375 # 1-11 & P. 389 # 1,7,9,12,15; P. 436 #1, 7, 8, 11
SCH3U- R.H.KING ACADEMY SOLUTION & ACID/BASE WORKSHEET Name: The importance of water - MAKING CONNECTION READING 1. Read P. 368-375, P. 382-387 & P. 429-436; P. 375 # 1-11 & P. 389 # 1,7,9,12,15; P. 436
More informationChem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses
Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses B. Calculations of moles C. Calculations of number of atoms from moles/molar masses 1. Avagadro
More informationChapter 3 Mass Relationships in Chemical Reactions
Chapter 3 Mass Relationships in Chemical Reactions Student: 1. An atom of bromine has a mass about four times greater than that of an atom of neon. Which choice makes the correct comparison of the relative
More informationChemistry Ch 15 (Solutions) Study Guide Introduction
Chemistry Ch 15 (Solutions) Study Guide Introduction Name: Note: a word marked (?) is a vocabulary word you should know the meaning of. A homogeneous (?) mixture, or, is a mixture in which the individual
More informationMolarity of Ions in Solution
APPENDIX A Molarity of Ions in Solution ften it is necessary to calculate not only the concentration (in molarity) of a compound in aqueous solution but also the concentration of each ion in aqueous solution.
More informationExperiment 3 Limiting Reactants
3-1 Experiment 3 Limiting Reactants Introduction: Most chemical reactions require two or more reactants. Typically, one of the reactants is used up before the other, at which time the reaction stops. The
More informationChem 1A Exam 2 Review Problems
Chem 1A Exam 2 Review Problems 1. At 0.967 atm, the height of mercury in a barometer is 0.735 m. If the mercury were replaced with water, what height of water (in meters) would be supported at this pressure?
More informationSpring 2009. kj mol 125 0-229 -92. H f. H rxn = Σ H f (products) - Σ H f (reactants)
Spring 2009 2. The reaction of an elemental halogen with an alkane is a very common reaction. The reaction between chlorine and butane is provided below. (NOTE: Questions a d and f pertain to this reaction.)
More informationStoichiometry. Lecture Examples Answer Key
Stoichiometry Lecture Examples Answer Key Ex. 1 Balance the following chemical equations: 3 NaBr + 1 H 3 PO 4 3 HBr + 1 Na 3 PO 4 2 C 3 H 5 N 3 O 9 6 CO 2 + 3 N 2 + 5 H 2 O + 9 O 2 2 Ca(OH) 2 + 2 SO 2
More informationMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Chapter 10 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A gas at a pressure of 10.0 Pa exerts a force of N on an area of 5.5 m2. A) 1.8 B) 0.55
More informationAN EXPERIMENT IN ALCHEMY: COPPER TO SILVER TO GOLD 2005, 2000, 1996 by David A. Katz. All rights reserved
AN EXPERIMENT IN ALCHEMY: COPPER TO SILVER TO GOLD 2005, 2000, 1996 by David A. Katz. All rights reserved INTRODUCTION One of the goals of the ancient alchemists was to convert base metals into gold. Although
More informationCP Chemistry Review for Stoichiometry Test
CP Chemistry Review for Stoichiometry Test Stoichiometry Problems (one given reactant): 1. Make sure you have a balanced chemical equation 2. Convert to moles of the known substance. (Use the periodic
More informationAtomic mass is the mass of an atom in atomic mass units (amu)
Micro World atoms & molecules Laboratory scale measurements Atomic mass is the mass of an atom in atomic mass units (amu) By definition: 1 atom 12 C weighs 12 amu On this scale 1 H = 1.008 amu 16 O = 16.00
More informationFormulas, Equations and Moles
Chapter 3 Formulas, Equations and Moles Interpreting Chemical Equations You can interpret a balanced chemical equation in many ways. On a microscopic level, two molecules of H 2 react with one molecule
More informationIntroductory Chemistry, 3 rd Edition Nivaldo Tro. Roy Kennedy Massachusetts Bay Community College Wellesley Hills, Maqqwertd ygoijpk[l
Introductory Chemistry, 3 rd Edition Nivaldo Tro Quantities in Car an octane and oxygen molecules and carbon dioxide and water Chemical Reactions Roy Kennedy Massachusetts Bay Community College Wellesley
More informationCHEM 36 General Chemistry EXAM #1 February 13, 2002
CHEM 36 General Chemistry EXAM #1 February 13, 2002 Name: Serkey, Anne INSTRUCTIONS: Read through the entire exam before you begin. Answer all of the questions. For questions involving calculations, show
More information5 Answers and Solutions to Text Problems
Energy and States of Matter 5 Answers and Solutions to Text Problems 5.1 At the top of the hill, all of the energy of the car is in the form of potential energy. As it descends down the hill, potential
More informationW1 WORKSHOP ON STOICHIOMETRY
INTRODUCTION W1 WORKSHOP ON STOICHIOMETRY These notes and exercises are designed to introduce you to the basic concepts required to understand a chemical formula or equation. Relative atomic masses of
More informationMoles. Moles. Moles. Moles. Balancing Eqns. Balancing. Balancing Eqns. Symbols Yields or Produces. Like a recipe:
Like a recipe: Balancing Eqns Reactants Products 2H 2 (g) + O 2 (g) 2H 2 O(l) coefficients subscripts Balancing Eqns Balancing Symbols (s) (l) (aq) (g) or Yields or Produces solid liquid (pure liquid)
More informationChapter 3: Stoichiometry
Chapter 3: Stoichiometry Key Skills: Balance chemical equations Predict the products of simple combination, decomposition, and combustion reactions. Calculate formula weights Convert grams to moles and
More information