# Apparatus error for each piece of equipment = 100 x margin of error quantity measured

Size: px
Start display at page:

Download "Apparatus error for each piece of equipment = 100 x margin of error quantity measured"

Transcription

1 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 itself. For example, no balance can measure an exact mass but a very expensive and high resolution balance may be able to measure a mass to the nearest g, while a cheaper, lower resolution balance may only measure it to the nearest 0.1 g. Errors such as this are known as apparatus error (uncertainties) and cannot be avoided, although they can be reduced by using the highest resolution equipment available. For example, when measuring out 25 cm 3 of a solution, a pipette is much offers higher resolution than a measuring cylinder. When you do quantitative experiments (those that require you to measure a quantity), you will have to calculate the total apparatus error from the sum of the apparatus error for each piece of equipment you use to make a measurement. Apparatus error for each piece of equipment = 100 x margin of error quantity measured For example, imagine a pupil doing an experiment where she measured out g of a base, make it up to 250 cm 3 of solution in a volumetric flask, pipetted 25 cm 3 of that solution into a conical flask, and then found that it reacted with cm 3 of acid in a titration using a burette. Balance (± g) 100 x (0.001/1.245) = 0.08% Pipette (± 0.1 cm 3 ) 100 x (0.1/25) = 0.40% Volumetric flask (± 0.1 cm 3 ) 100 x (0.1/250) = 0.04% Burette (± 0.15 cm 3 ) 100 x (0.15/23.30) = 0.64% Total apparatus error = 1.16% This means that the result of the experiment should be within 1.16% of the correct value. When experiments are designed, we aim to ensure that the total apparatus error is minimised by working on a suitable scale and with suitable apparatus. A very small titre for example (e.g. 5 cm 3 ) leads to a very large apparatus error for the burette (3%). Experimental Errors When you do an experiment you will make some small errors due to your technique being less than perfect. You can calculate your experimental error as shown: Experimental error = 100 x (real answer experiment answer) real answer If experimental error is smaller than apparatus error, then you have an accurate result. However, if experimental error is larger than apparatus error, then the result is inaccurate. For example, imagine in the experiment above that the acid concentration was being measured and was found to be mol dm -3 compared to the real value of mol dm -3. Experimental error = 100 x ( ) = 1.49% The experimental error (1.49%) is greater than the apparatus error (1.16%) meaning that the results are inaccurate Jul-12 Chemsheets AS 062 1

3 3) Organic preparations a) The Reaction The reactants are measured out either by mass or volume. If volume is used for a liquid, its mass can be calculated from its density. The reactants are mixed in suitable apparatus. This could be a beaker, a conical flask, or a Quik-Fit flask. If the reactants need to be cooled, then an ice bath is used. If the reactants need to be heated, then they are usually refluxed. This allows the reactants (and products) to be heated but not escape from the reaction vessel (as heating causes them to evaporate or even boil). Any escaping vapour condenses and falls back into the flask. Any bumping granules are placed in the flask to prevent bumping, that is the sudden release of a large bubble of vapour that makes the reaction mixture jump up. The anti-bumping granules produces many small bubbles rather than a large one. refluxing b) Separating the product from the reaction mixture Chemists often talk of working up the reaction. This is where the crude (impure) product is separated from the reaction mixture. The method used depends on whether the product is a solid or a liquid. If the product is a liquid: The product is usually collected by distillation of the reaction mixture. The apparatus is set up for distillation and the chemicals boiling at a range close to that of the product collected (e.g. 15ºC range). If the product is a solid: The product is usually collected by filtration from the reaction mixture. Sometimes the product forms as a solid in the reaction, but in other reactions something (e.g. cold water) has to be added to cause the product to form as a solid from solution. The solid is them separated by filtration under reduced pressure using Buchner apparatus. mixture 12-Jul-12 Chemsheets AS 062 3

4 c) Purifying the product The product separated will be impure and needs to be purified. Solids are usually purified by re-crystallisation. The principle is that the product is dissolved in the minimum amount of a hot solvent to create a solution saturated with the product. Any insoluble impurities can be filtered out (but the apparatus must be heated so the solution does not cool as it is filtered). The saturated solution is then allowed to cool slowly, and so the product crystallises out from the solution while any other impurities remain dissolved. Cooling to room temperature may suffice, or an ice bath may be needed. However, if the saturated solution is cooled too quickly, many of the impurities crystallise out as well. Liquids are usually purified by a) Putting in a separating funnel with solvents / reagents that do not mix with the product, but in which impurities may dissolve. This usually involves water or water based solutions as most organic compounds are immiscible with water. For example, the product here has been mixed with hydrochloric acid in which any left over reactants would dissolve. b) If water has been used above, then the product is left to dry by adding a chemical that absorbs water, such as anhydrous sodium sulphate or anhydrous calcium chloride. c) Finally, the product is distilled again to give a pure product. This time, the product is collected over a much narrower range of temperatures (e.g. 5ºC). d) Testing the purity of the product A good test of purity is to see what temperature the product boils or melts at. It will boil / melt over a range of temperatures. The smaller the range (say 2ºC) and the closer this range to the correct value, the purer the product. For a liquid, the boiling point is usually measured during the final distillation. For a solid, the melting point is measured by putting a small sample into a capillary tube and strapping it onto a thermometer. The thermometer is placed in a boiling tube half full with dibutyl phthalate and heated, stirring with the rod. Once you know roughly where it melts, the experiment is repeated heating to within 30 C of the melting point and then heating very slowly to measure the exact melting range. e) Measuring the yield We also want to know how much product we have made. This is usually recorded as a percentage yield. For example, if a reaction should theoretically make 2 g of a product, but only 0.5 g is formed, then it is a 25% yield. % Yield = moles of product formed x 100 moles of product formed theoretically 12-Jul-12 Chemsheets AS 062 4

5 For example, in the formation of cyclohexene from cyclohexanol. Imagine that 0.45 g of cyclohexene was formed from 1.0 g of cyclohexanol. OH heat conc. H 3 PO 4 + H 2 O cyclohexanol cyclohexene Moles cyclohexanol = mass / M r = 1.0 / 100 = 0.01 Moles cyclohexene theoretically produced = 0.01 Mass of cyclohexene theoretically produced = moles x M r = 82.0 x 0.01 = 0.82 g % Yield = 100 x 0.45 = 55 % ) Kinetics The key problem with kinetics practicals is any variation in temperature, as a small change in temperature has a big impact on reaction rate. Controlling the temperature, for example by using a thermostatically controlled water bath, would improve the experiment. When recording times, usually the nearest second is appropriate. At A2, you may need to plot a log graph to find order with respect to a particular reagent. log (1/time) You should plot log (1/time) on the y axis against log (volume reagent) on the x axis. You should ensure that for each axis you use more than half of the available space. When calculating the gradient, choose two points near opposite ends of the line and remember it is change in y over change in x. Remember that the final order should be a whole number. Gradient = change in y change in x log (volume reagent) 5) Test tube observations You will often have to carry out test tube reactions and record your observations. You must indicate what the reagents were like before mixing and what they were during/after mixing. You must clearly state the colour and whether they are solids or solutions. Some good examples are shown below: Reaction addition of acidified silver nitrate to a solution of sodium chloride acidified potassium dichromate (VI) with propan-1-ol addition of sodium hydrogencarbonate with ethanoic acid Observation colourless solution white precipitate orange solution green solution colourless solution fizzing and colourless solution 12-Jul-12 Chemsheets AS 062 5

6 6) Calorimetry If the mass of the water is known (the mass of water = volume of water in grams, e.g. 50 cm 3 of water has a mass of 50 g) and the temperature rise (fall), then the heat released (or absorbed) can be calculated. The enthalpy change for a reaction can be found by measuring the temperature change in a reaction. The heat energy given out (or taken in) is used to heat (or cool) a known mass of water. We know that it takes 4.18 J of energy to raise the temperature of 1 g of water by 1 C (i.e. 1 K). The amount of energy needed to make 1 g of a substance 1 C (1 K) hotter is called the specific heat capacity (measured in J g -1 K -1 ). The following equation is then used to find the amount of heat energy give out (or absorbed). q = mc T q = heat energy given out (J) m = mass of substance heated (g) T = temperature rise (K) c = specific heat capacity (J g -1 K -1 ) = 4.18 J g -1 K -1 for water To find the enthalpy change in terms of J (or kj) per mole, the following expression is needed: (THINK kj per mole!) Enthalpy change (per mole) = q. number of moles reacting For reactions in solution, the reaction is typically done in a supported polystyrene cup (with lid). For combustion reactions, the substance is burned under a copper calorimeter containing water. For reactions in solution, if the reaction is very fast, the difference between the starting temperature and the highest temperature recorded is the temperature rise. For most reactions in solution, the temperature is recorded every minute (or 30 s) or so and the results plotted on a graph. Axes should be chosen so the plot uses more than half of the available space on each axis. The graph can be extrapolated back to the time at which the reagents were mixed to find the temperature change. NB temperatures before the maximum temperature in an exothermic reaction (or minimum temperature for an endothermic reaction) should be ignored when determining the best fit line (which could be a curve or straight line). The main problem with calorimetry experiments is heat loss. This can only be reduced by using a better insulated calorimeter. 7) Significant figures, etc. General rule work to 3 significant figures (unless other rules supercede it) General rule give M r s to one decimal place (unless other rules supercede it) Titrations give all burette readings to the nearest 0.05 cm 3 (e.g cm 3 not 26.4 cm 3 ) Titrations give the mean titre to 2 decimal places Water of crystallisation this should be a whole number Calorimetry give all temperatures and the temperature change to the nearest 0.1 C Kinetics record times measured to the nearest second Kinetics order of reactions should be a whole number 12-Jul-12 Chemsheets AS 062 6

### 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

### Acetic Acid Content of Vinegar: An Acid-Base Titration E10-1

Experiment 10 Acetic Acid Content of Vinegar: An Acid-Base Titration E10-1 E10-2 The task The goal of this experiment is to determine accurately the concentration of acetic acid in vinegar via volumetric

### experiment5 Understanding and applying the concept of limiting reagents. Learning how to perform a vacuum filtration.

81 experiment5 LECTURE AND LAB SKILLS EMPHASIZED Synthesizing an organic substance. Understanding and applying the concept of limiting reagents. Determining percent yield. Learning how to perform a vacuum

### hij Teacher Resource Bank GCE Chemistry PSA10: A2 Inorganic Chemistry Carry out a redox titration

hij Teacher Resource Bank GCE Chemistry : A2 Inorganic Chemistry Copyright 2009 AQA and its licensors. All rights reserved. The Assessment and Qualifications Alliance (AQA) is a company limited by guarantee

### Recovery 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

### GCE Chemistry PSA14: A2 Physical Chemistry Determine an equilibrium contstant

hij Teacher Resource Bank GCE Chemistry : A2 Physical Chemistry Determine an equilibrium contstant Copyright 2009 AQA and its licensors. All rights reserved. The Assessment and Qualifications Alliance

### Stoichiometry Limiting Reagent Laboratory. Chemistry 118 Laboratory University of Massachusetts, Boston

Chemistry 118 Laboratory University of Massachusetts, Boston STOICHIOMETRY - LIMITING REAGENT --------------------------------------------------------------------------------------------------------------------------------------------

### PURIFICATION TECHNIQUES

DETERMINACIÓN DE ESTRUCTURAS ORGÁNICAS (ORGANIC SPECTROSCOPY) PURIFICATION TECHNIQUES Hermenegildo García Gómez Departamento de Química Instituto de Tecnología Química Universidad Politécnica de Valencia

### Hands-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.

### PREPARATION 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

### Q1. A student studied the reaction between dilute hydrochloric acid and an excess of calcium carbonate.

Q. A student studied the reaction between dilute hydrochloric acid and an excess of calcium carbonate. calcium carbonate + hydrochloric acid calcium chloride + water + carbon dioxide The student measured

### Stoichiometry Limiting Reagent Laboratory. Chemistry 118 Laboratory University of Massachusetts, Boston

Chemistry 118 Laboratory University of Massachusetts, Boston STOICHIOMETRY - LIMITING REAGENT -----------------------------------------------------------------------------------------------------------------------------

### The most common active ingredient used in deodorants is aluminium chlorohydrate. But not all deodorants contain aluminium chlorohydrate:

Engineeringfragrance make a deodorant practical activity 2 student instructions page 1 of 5 chemical compounds The most common active ingredient used in deodorants is aluminium chlorohydrate. But not all

### CHEM 2423 Recrystallization of Benzoic Acid EXPERIMENT 4 - Purification - Recrystallization of Benzoic acid

EXPERIMENT 4 - Purification - Recrystallization of Benzoic acid Purpose: a) To purify samples of organic compounds that are solids at room temperature b) To dissociate the impure sample in the minimum

### ACID-BASE TITRATIONS: DETERMINATION OF CARBONATE BY TITRATION WITH HYDROCHLORIC ACID BACKGROUND

#3. Acid - Base Titrations 27 EXPERIMENT 3. ACID-BASE TITRATIONS: DETERMINATION OF CARBONATE BY TITRATION WITH HYDROCHLORIC ACID BACKGROUND Carbonate Equilibria In this experiment a solution of hydrochloric

### MEASUREMENTS AND ERRORS

Measurements 1 MESUREMENTS ND ERRORS ccuracy Error Precision Uncertainty Reliability measure of the closeness of agreement between an individual result and the accepted value. n accurate result is in close

### COMMON LABORATORY APPARATUS

COMMON LABORATORY APPARATUS Beakers are useful as a reaction container or to hold liquid or solid samples. They are also used to catch liquids from titrations and filtrates from filtering operations. Bunsen

### Determination 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

### Physical and Chemical Properties and Changes

Physical and Chemical Properties and Changes An understanding of material things requires an understanding of the physical and chemical characteristics of matter. A few planned experiments can help you

### Mixtures and Pure Substances

Unit 2 Mixtures and Pure Substances Matter can be classified into two groups: mixtures and pure substances. Mixtures are the most common form of matter and consist of mixtures of pure substances. They

### 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

### 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

### In this experiment, we will use three properties to identify a liquid substance: solubility, density and boiling point..

Identification of a Substance by Physical Properties 2009 by David A. Katz. All rights reserved. Permission for academic use provided the original copyright is included Every substance has a unique set

### Experiment 12- Classification of Matter Experiment

Experiment 12- Classification of Matter Experiment Matter can be classified into two groups: mixtures and pure substances. Mixtures are the most common form of matter and consist of mixtures of pure substances.

### Syllabus OC18 Use litmus or a universal indicator to test a variety of solutions, and classify these as acidic, basic or neutral

Chemistry: 9. Acids and Bases Please remember to photocopy 4 pages onto one sheet by going A3 A4 and using back to back on the photocopier Syllabus OC18 Use litmus or a universal indicator to test a variety

### ISOLATION OF CAFFEINE FROM TEA

ISLATIN F CAFFEINE FRM TEA Introduction In this experiment, caffeine is isolated from tealeaves. The chief problem with the isolation is that caffeine does not exist alone in the tealeaves, but other natural

### 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

### Experiment 8 Preparation of Cyclohexanone by Hypochlorite Oxidation

Experiment 8 Preparation of Cyclohexanone by ypochlorite xidation In this experiment we will prepare cyclohexanone from cyclohexanol using hypochlorite oxidation. We will use common household bleach that

### To measure the solubility of a salt in water over a range of temperatures and to construct a graph representing the salt solubility.

THE SOLUBILITY OF A SALT IN WATER AT VARIOUS TEMPERATURES 2007, 1995, 1991 by David A. Katz. All rights reserved. Permission for academic use provided the original copyright is included. OBJECTIVE To measure

### 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

### Estimation of Alcohol Content in Wine by Dichromate Oxidation followed by Redox Titration

Sirromet Wines Pty Ltd 850-938 Mount Cotton Rd Mount Cotton Queensland Australia 4165 www.sirromet.com Courtesy of Jessica Ferguson Assistant Winemaker & Chemist Downloaded from seniorchem.com/eei.html

### PHYSICAL 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

### Experiment 8 Synthesis of Aspirin

Experiment 8 Synthesis of Aspirin Aspirin is an effective analgesic (pain reliever), antipyretic (fever reducer) and anti-inflammatory agent and is one of the most widely used non-prescription drugs. The

### 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

### 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,

### 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

### EDTA Titrations 1: Standardization of EDTA and Analysis of Zinc in a Supplement Tablet. by Professor David Cash. September, 2008

CHEMICAL, ENVIRONMENTAL, AND BIOTECHNOLOGY DEPARTMENT EDTA Titrations 1: Standardization of EDTA and Analysis of Zinc in a Supplement Tablet by Professor David Cash September, 2008 Mohawk College is the

### PREPARATION AND PROPERTIES OF A SOAP

(adapted from Blackburn et al., Laboratory Manual to Accompany World of Chemistry, 2 nd ed., (1996) Saunders College Publishing: Fort Worth) Purpose: To prepare a sample of soap and to examine its properties.

### To see how this data can be used, follow the titration of hydrofluoric acid against sodium hydroxide below. HF (aq) + NaOH (aq) H2O (l) + NaF (aq)

Weak Acid Titration v120413 You are encouraged to carefully read the following sections in Tro (2 nd ed.) to prepare for this experiment: Sec 4.8, pp 158-159 (Acid/Base Titrations), Sec 16.4, pp 729-43

### Simulation of the determination of lead azide content in waste water from explosives manufacture

Simulation of the determination of lead azide content in waste water from explosives manufacture Lead azide ranks in the category of intensive explosives, which may, even in an insignificant amount, initiate

### EXPERIMENT 9 (Organic Chemistry II) Pahlavan - Cherif Synthesis of Aspirin - Esterification

EXPERIMENT 9 (rganic hemistry II) Pahlavan - herif Materials Hot plate 125-mL Erlenmeyer flask Melting point capillaries Melting point apparatus Büchner funnel 400-mL beaker Stirring rod hemicals Salicylic

### STANDARDIZATION OF A SODIUM HYDROXIDE SOLUTION EXPERIMENT 14

STANDARDIZATION OF A SODIUM HYDROXIDE SOLUTION EXPERIMENT 14 OBJECTIVE The objective of this experiment will be the standardization of sodium hydroxide using potassium hydrogen phthalate by the titration

### HS 1003 Part 2 HS 1003 Heavy Metals Test

HS 1003 Heavy Metals Test 1. Purpose This test method is used to analyse the heavy metal content in an aliquot portion of stabilised hot acetic acid extract by Atomic Absorption Spectroscopy (AAS). Note:

### 4.0 EXPERIMENT ON DETERMINATION OF CHLORIDES

4.0 EXPERIMENT ON DETERMINATION OF CHLORIDES Sl. No. Contents Preamble 4.1 Aim 4.2 Introduction 4.2.1 Environmental Significance 4.3 Principle 4.4 Materials Required 4.4.1 Apparatus Required 4.4.2 Chemicals

### Coordination Compounds with Copper (II) Prelab (Week 2)

Coordination Compounds with Copper (II) Prelab (Week 2) Name Total /10 SHOW ALL WORK NO WORK = NO CREDIT 1. What is the purpose of this experiment? 2. Write the generic chemical formula for the coordination

### Isolation of Caffeine from Tea

Isolation of Caffeine from Tea Introduction A number of interesting, biologically active compounds have been isolated from plants. Isolating some of these natural products, as they are called, can require

### Experiment 3: Extraction: Separation of an Acidic, a Basic and a Neutral Substance

1 Experiment 3: Extraction: Separation of an Acidic, a Basic and a Neutral Substance Read pp 142-155, 161-162, Chapter 10 and pp 163-173, Chapter 11, in LTOC. View the videos: 4.2 Extraction (Macroscale);

### Experiment 7: Titration of an Antacid

1 Experiment 7: Titration of an Antacid Objective: In this experiment, you will standardize a solution of base using the analytical technique known as titration. Using this standardized solution, you will

### EXPERIMENT 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

### Acid Base Titrations

Acid Base Titrations Introduction A common question chemists have to answer is how much of something is present in a sample or a product. If the product contains an acid or base, this question is usually

### 5. 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( )

### MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Chemistry 5.310 Laboratory Chemistry THE POTENTIOMETRIC TITRATION OF AN ACID MIXTURE 1

MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Chemistry 5.310 Laboratory Chemistry EXPERIMENT #5 THE POTENTIOMETRIC TITRATION OF AN ACID MIXTURE 1 I. PURPOSE OF THE EXPERIMENT In this experiment

### CHM220 Nucleophilic Substitution Lab. Studying S N 1 and S N 2 Reactions: Nucloephilic Substitution at Saturated Carbon*

CHM220 Nucleophilic Substitution Lab Studying S N 1 and S N 2 Reactions: Nucloephilic Substitution at Saturated Carbon* Purpose: To convert a primary alcohol to an alkyl bromide using an S N 2 reaction

### Saturated NaCl solution rubber tubing (2) Glass adaptor (2) thermometer adaptor heating mantle

EXPERIMENT 5 (Organic Chemistry II) Pahlavan/Cherif Dehydration of Alcohols - Dehydration of Cyclohexanol Purpose - The purpose of this lab is to produce cyclohexene through the acid catalyzed elimination

### WATER EQUIVALENT OF THE CALORIMETER

. Thermochemistry Experiment.. WATER EQUIVALENT OF THE CALORIMETER Aim: To determine the water equivalent of the given calorimeter. Principle: A thermos flask of about 00 cm 3 capacity fitted with a thermometer

### Separation by Solvent Extraction

Experiment 3 Separation by Solvent Extraction Objectives To separate a mixture consisting of a carboxylic acid and a neutral compound by using solvent extraction techniques. Introduction Frequently, organic

### IB 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

### BLOWING UP BALLOONS, chemically

BLOWING UP BALLOONS, chemically PRE LAB DISCUSSION: Today we will be using a closed system. A closed system does not permit matter to enter or exit the apparatus. Lavoisier's classic 12-day experiment,

### Recrystallization II 23

Recrystallization II 23 Chem 355 Jasperse RECRYSTALLIZATIN-Week 2 1. Mixed Recrystallization of Acetanilide 2. Mixed Recrystallization of Dibenzylacetone 3. Recrystallization of an Unknown Background Review:

### SOLUBILITY, IONIC STRENGTH AND ACTIVITY COEFFICIENTS

SOLUBILITY, IONIC STRENGTH AND ACTIVITY COEFFICIENTS References: 1. See `References to Experiments' for text references.. W. C. Wise and C. W. Davies, J. Chem. Soc., 73 (1938), "The Conductivity of Calcium

### Chemistry 112 Laboratory Experiment 6: The Reaction of Aluminum and Zinc with Hydrochloric Acid

Chemistry 112 Laboratory Experiment 6: The Reaction of Aluminum and Zinc with Hydrochloric Acid Introduction Many metals react with acids to form hydrogen gas. In this experiment, you will use the reactions

### CHEMICAL 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

### Making Biodiesel from Virgin Vegetable Oil: Teacher Manual

Making Biodiesel from Virgin Vegetable Oil: Teacher Manual Learning Goals: Students will understand how to produce biodiesel from virgin vegetable oil. Students will understand the effect of an exothermic

### Specimen Paper. Time allowed! 60 minutes

Centre Number Surname Candidate Number Specimen Paper For Examiner s Use Other Names Candidate Signature Examiner s Initials General Certificate of Secondary Education Foundation Tier Question 1 Mark Chemistry

### EXPERIMENT 2 THE HYDROLYSIS OF t-butyl CHLORIDE. PURPOSE: To verify a proposed mechanism for the hydrolysis of t-butyl Chloride.

PURPOSE: To verify a proposed mechanism for the hydrolysis of t-butyl Chloride. PRINCIPLES: Once the Rate Law for a reaction has been experimentally established the next step is its explanation in terms

### Calibration of Volumetric Glassware

Chemistry 119: Experiment 2 Calibration of Volumetric Glassware For making accurate measurements in analytical procedures, next in importance to the balance is volumetric equipment. In this section volumetric

### Acid-Base Extraction.

Acid-Base Extraction. Extraction involves dissolving a compound or compounds either (1) from a solid into a solvent or (2) from a solution into another solvent. A familiar example of the first case is

### SODIUM CARBOXYMETHYL CELLULOSE

SODIUM CARBOXYMETHYL CELLULOSE Prepared at the 28th JECFA (1984), published in FNP 31/2 (1984) and in FNP 52 (1992). Metals and arsenic specifications revised at the 55 th JECFA (2000). An ADI not specified

### Taking Apart the Pieces

Lab 4 Taking Apart the Pieces How does starting your morning out right relate to relief from a headache? I t is a lazy Saturday morning and you ve just awakened to your favorite cereal Morning Trails and

### Desalination of Sea Water E7-1

Experiment 7 Desalination of Sea Water E7-1 E7-2 The Task The goal of this experiment is to investigate the nature and some properties of sea water. Skills At the end of the laboratory session you should

### Page 1 of 5. Purification of Cholesterol An Oxidative Addition-Reductive Elimination Sequence

Page 1 of 5 Purification of Cholesterol An Oxidative Addition-Reductive Elimination Sequence From your lectures sessions in CEM 2010 you have learned that elimination reactions may occur when alkyl halides

### AN 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

### ANALYSIS OF FOOD AND NATURAL PRODUCTS LABORATORY EXERCISE

ANALYSIS OF FOOD AND NATURAL PRODUCTS LABORATORY EXERCISE Determination of total nitrogen in food and crude protein calculation (Kjeldahl method) Responsible person: Assoc.Prof. Ing.Kateřina Riddellová,

### Physical Properties of a Pure Substance, Water

Physical Properties of a Pure Substance, Water The chemical and physical properties of a substance characterize it as a unique substance, and the determination of these properties can often allow one to

### Solubility Curve of Sugar in Water

Solubility Curve of Sugar in Water INTRODUCTION Solutions are homogeneous mixtures of solvents (the larger volume of the mixture) and solutes (the smaller volume of the mixture). For example, a hot chocolate

### Determination of the Amount of Acid Neutralized by an Antacid Tablet Using Back Titration

Determination of the Amount of Acid Neutralized by an Antacid Tablet Using Back Titration GOAL AND OVERVIEW Antacids are bases that react stoichiometrically with acid. The number of moles of acid that

### 4026 Synthesis of 2-chloro-2-methylpropane (tert-butyl chloride) from tert-butanol

4026 Synthesis of 2-chloro-2-methylpropane (tert-butyl chloride) from tert-butanol OH + HCl Cl + H 2 O C 4 H 10 O C 4 H 9 Cl (74.1) (36.5) (92.6) Classification Reaction types and substance classes nucleophilic

### Experiment 1: Colligative Properties

Experiment 1: Colligative Properties Determination of the Molar Mass of a Compound by Freezing Point Depression. Objective: The objective of this experiment is to determine the molar mass of an unknown

### Preparation of an Alum

Preparation of an Alum Pages 75 84 Pre-lab = pages 81 to 82, all questions No lab questions, a lab report is required by the start of the next lab What is an alum? They are white crystalline double sulfates

### Mark Scheme (Results) January 2012. International GCSE Chemistry (4CH0) Paper 2C

Mark Scheme (Results) January 202 International GCSE Chemistry (4CH0) Paper 2C Edexcel and BTEC Qualifications Edexcel and BTEC qualifications come from Pearson, the world s leading learning company. We

### EXPERIMENT FIVE. Preparation of Cyclohexene from Cyclohexanol: an Elimination Reaction DISCUSSION

EXPERIMENT FIVE Preparation of Cyclohexene from Cyclohexanol: an Elimination Reaction DISCUSSION A secondary alcohol, such as cyclohexanol, undergoes dehydration by an E1 mechanism. The key intermediate

### The introduction of your report should be written on the on the topic of the role of indicators on acid base titrations.

Experiment # 13A TITRATIONS INTRODUCTION: This experiment will be written as a formal report and has several parts: Experiment 13 A: Basic methods (accuracy and precision) (a) To standardize a base (~

### Instructions 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

### Carolina s Solution Preparation Manual

84-1201 Carolina s Solution Preparation Manual Instructions Carolina Biological Supply Company has created this reference manual to enable you to prepare solutions. Although many types of solutions may

### Reaction of Magnesium with Hydrochloric Acid (Gas Laws) Chemicals Needed:

Reaction of Magnesium with Hydrochloric Acid (Gas Laws) Your Name: Date: Partner(s) Names: Objectives: React magnesium metal with hydrochloric acid, collecting the hydrogen over water. Calculate the grams

### MOISTURE (Karl Fischer, Buffered)

MOIST.03-1 MOISTURE (Karl Fischer, Buffered) PRINCIPLE SCOPE The sample is dissolved in a mixture of methanol and formamide (50:50 v/v) and then titrated with standardized Karl Fischer reagent. The titration

### PECTINS. SYNONYMS INS No. 440 DEFINITION DESCRIPTION. FUNCTIONAL USES Gelling agent, thickener, stabilizer, emulsifier CHARACTERISTICS

PECTINS SYNONYMS INS No. 440 Prepared at the 71 st JECFA (2009) and published in FAO JECFA Monographs 7 (2009), superseding specifications prepared at the 68 th JECFA (2007) and published in FAO JECFA

### Practical 1: Measure the molar volume of a gas

Practical Student sheet Practical : Wear eye protection. Ensure the delivery tube does not become blocked. Ethanoic acid will sting if it gets into cuts in the skin. Equipment boiling tube stand and clamp

### Paper 1 (7404/1): Inorganic and Physical Chemistry Mark scheme

AQA Qualifications AS Chemistry Paper (7404/): Inorganic and Physical Chemistry Mark scheme 7404 Specimen paper Version 0.6 MARK SCHEME AS Chemistry Specimen paper Section A 0. s 2 2s 2 2p 6 3s 2 3p 6

### Pre-Lab Notebook Content: Your notebook should include the title, date, purpose, procedure; data tables.

Determination of Molar Mass by Freezing Point Depression M. Burkart & M. Kim Experimental Notes: Students work in pairs. Safety: Goggles and closed shoes must be worn. Dispose of all chemical in the plastic

### A Beer s Law Experiment

A Beer s Law Experiment Introduction There are many ways to determine concentrations of a substance in solution. So far, the only experiences you may have are acid-base titrations or possibly determining

### CSUS Department of Chemistry Experiment 8 Chem.1A

EXPERIMENT #8 Name: PRE-LABORATORY ASSIGNMENT: Lab Section 1. The alkali metals are so reactive that they react directly with water in the absence of acid. For example, potassium reacts with water as follows:

### n molarity = M = N.B.: n = litres (solution)

1. CONCENTRATION UNITS A solution is a homogeneous mixture of two or more chemical substances. If we have a solution made from a solid and a liquid, we say that the solid is dissolved in the liquid and

### AQA CERTIFICATE Science: Double Award

AQA CERTIFICATE Science: Double Award 8404/C/2H Mark scheme 8404 June 205 Version/Stage:.0 Final Mark schemes are prepared by the Lead Assessment Writer and considered, together with the relevant questions,

### EXPERIMENT 3 (Organic Chemistry II) Nitration of Aromatic Compounds: Preparation of methyl-m-nitrobenzoate

EXPERIMENT 3 (Organic Chemistry II) Nitration of Aromatic Compounds: Preparation of methyl-m-nitrobenzoate Pahlavan/Cherif Purpose a) Study electrophilic aromatic substitution reaction (EAS) b) Study regioselectivity

### Phase Diagram of tert-butyl Alcohol

Phase Diagram of tert-butyl Alcohol Bill Ponder Department of Chemistry Collin College Phase diagrams are plots illustrating the relationship of temperature and pressure relative to the phase (or state

### How to prepare standard solutions

World Bank & Government of The Netherlands funded Training module # WQ -04 How to prepare standard solutions New Delhi, May 1999 CSMRS Building, 4th Floor, Olof Palme Marg, Hauz Khas, New Delhi 11 00 16

### Chapter 16: Tests for ions and gases

The position of hydrogen in the reactivity series Hydrogen, although not a metal, is included in the reactivity series because it, like metals, can be displaced from aqueous solution, only this time the