Chemistry Pre-Lab

CHEMISTRY 1
SK015

SK015

Pre-Lab Module

EXPERIMENT 1
DETERMINATION OF THE FORMULA UNIT OF A COMPOUND

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical
chemistry. (C4, PLO4, CTPS3, MQF LO6)

Learning Outcomes:

At the end of this lesson, students should be able to:
i. Define the terms compound, formula unit, empirical formula and molecular formula
ii. Determine the formula unit of a compound

iii. Identify the safety precautions of the experiment

Student Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Direction: Read over the lab manual and then answer the following question.

Introduction:
1. Define the term compound.

2. What is a formula unit of a compound?

3. State the difference between empirical formula and molecular formula.

4. The formula unit of a compound can be determined if the composition or the ratio of the
elements in the compound is known. Consider a compound that contains 0.20 mole of
aluminum and 0.30 mole of oxygen. Determine its formula unit.

SK015

Pre-Lab Module

Procedure:
1. List the safety cautions in this experiment.

2. The compound should not be heated to the point that it melts. Explain.
3. Why is the compound reheated, cooled and reweighed after the first heating?
4. Construct a table to record the data for the experiment.

SK015

Pre-Lab Module

Experiment 1 : Data Analysis

An experiment was conducted to determine the formula unit of magnesium oxide. The
following data was recorded.

Mass of empty crucible + lid = 24.0037 g
Mass of crucible + lid + magnesium strip = 24.3046 g
Mass of crucible + lid + magnesium oxide:
a) after first heating = 24.5278 g
b) after second heating = 24.5097 g

Determine the formula unit of the compound.

SK015

Pre-Lab Module

EXPERIMENT 2
ACID-BASE TITRATION - DETERMINATION OF THE CONCENTRATION

OF HYDROCHLORIC ACID SOLUTION

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical
chemistry. (C4, PLO4, CTPS3, MQF LO6)

Learning Outcomes:

At the end of this lesson, students will be able:
i. To define molarity and standard solution
ii. To state the use of standard solution

iii. To describe the preparation of a standard solution of oxalic acid
iv. To differentiate between end point and equivalnce point.
v. To explain the precautions required during titration
vi. To calculate the concentration of HCl solution in an acid-base titration

Student-Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Direction: Read over the lab manual and then answer the following question.

Introduction
1. Define molarity.

2. What is a standard solution? State the use of a standard solution.

3. What is the difference between end point and equivalence point?

SK015

Pre-Lab Module

Procedure

1. State three precautions that must be taken during titration to ensure the accuracy of
results. State a reason for each precaution.

2. Briefly describe how to prepare 250 mL standard solution of hydrated oxalic acid
(C2H2O4.2H2O) with a concentration of 0.25 M.

3. How to determine the end point of the titration?

SK015

Pre-Lab Module

Experiment 2 : Data Analysis

A titration of 25.00 mL of an x M HCl solution with 0.15 M NaOH starts at a burette reading
for NaOH of 0.20 mL. The burette reading of the end point is 24.10 mL.

i. What was the volume of NaOH dispensed?
ii. Calculate the number of moles of NaOH dispensed.
iii. Write the balanced equation for the neutralisation reaction.
iv. Calculate the number of moles of HCl present in the acid solution.
v. Determine the value of x.

SK015

Pre-Lab Module

EXPERIMENT 3
DETERMINATION OF THE MOLAR MASS OF A METAL

Course Learning Outcome:
Solve chemistry related problems by applying basic concepts and principles in physical
chemistry. (C4, PLO4, CTPS3, MQF LO6)

Learning Outcomes:
At the end of this lesson, students will be able:

i. To determine the molar mass of an alkaline earth metal by back-titration method.

Student-Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Direction: Read over the lab manual and then answer the following question.
Introduction:

1. What is back-titration?

2. Give one example of alkaline earth metal and write the equation for the reaction between
the metal and HCl.

Procedure:
Explain briefly how to determine the molar mass of an unknown metal by using back-
titration method.

SK015

Pre-Lab Module

Experiment 3 : Data Analysis

A 0.2730 g sample of unknown metal, Y with oxidation number of +2, was completely
reacted with 25.00 mL of 0.50 M excess HCl. The remaining solution required 4.15 mL of
1.00 M NaOH to reach end point. Calculate the,

i. number of mole of HCl reacted with NaOH.
ii. number of mole of HCl reacted with Y.
iii. number of mole of Y metal reacted.
iv. molar mass of Y.

SK015

Pre-Lab Module

EXPERIMENT 4
CHARLES’ LAW AND THE IDEAL GAS LAW

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical
chemistry. (C4, PLO4, CTPS3, MQF LO6)

Learning Outcomes:

At the end of this lesson, students will be able to:
i. verify Charles’ Law by using graphical method.
ii. determine the molar mass of a volatile liquid.

Student-Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Direction: Read over the lab manual and then answer the following question.

Introduction
(A) Verify Charles’ Law.
1. Define Charles’ Law.

2. Based on kinetic molecular theory, describe how the volume of gas changes when the
temperature increases.

3. What variables are held constant in Charles’ Law?

SK015

Pre-Lab Module

(B) Determination of the molar mass of a volatile liquid.
1. State the ideal gas equation.

2. Derive the formula that relates the mass and the molar mass by using the ideal gas
equation.

3. What is the unit of molar mass?

Procedure
(A) Verify Charles’ Law.
Why should we use the same Charles’ law apparatus at all four different temperature?

(B) Determination of the molar mass of a volatile liquid.
1. Why do you need to prick a tiny hole in the middle of the aluminium foil?

2. When does the temperature of the water in beaker have to be recorded?

3. Why the conical flask is filled with water up to the brim?

SK015

Pre-Lab Module

Experiment 4 : Data Analysis
V

1. Mark the absolute zero temperature in the graph above. What is the volume of the gas at
this temperature?

2. Based on the graph, state the relationship between volume of the gas, V and absolute
temperature, T(K).

3. A 0.30 g of gas Y at 3.00 atm occupies 82.0 mL flask. Calculate the molar mass of gas Y
if temperature of the gas is 27.0oC.

4. State the possible errors in the experiment.

SK015

Pre-Lab Module

EXPERIMENT 5
CHEMICAL EQUILIBRIUM

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical
chemistry. (C4, PLO4, CTPS3, MQF LO6)

Learning Outcomes:

At the end of this lesson, students will be able to:
i. study the effect of concentration and temperature on chemical equilibrium.
ii. determine the equilibrium constant, Kc of a reaction

Student-Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Direction: Read over the lab manual and then answer the following question.

Introduction
1. What is meant by reversible reaction?

2. State two characteristics of dynamic equilibrium.

3. State Le Chatelier’s Principle.

4. State the factors that influence the chemical equilibrium.

SK015

Pre-Lab Module

5. Given the equation which is in equilibrium:

N2(g) + 3H2(g) 2NH3(g) ∆H = -92.83 kJ

Predict the direction of equilibrium if :

i. nitrogen gas is added

ii. gas is removed

iii. temperature of the system is increased.

6. Given the equation in equilibrium:

SbCl3(aq) + H2O(l) SbOCl(s) + 2HCl(aq)

i. Write the Kc expression for the above system

ii. Explain why H2O(l) and SbOCl(s) are not included in Kc expression.

Procedure
1. State the precautions for these experiments.

SK015

Pre-Lab Module

Experiment 5 : Data Analysis

(A) The effect of concentration in the formation of thiocyanoiron (III) complex ion

1.Given the equation [ Fe(SCN)2]+(aq)
(blood-red)
Fe3+(aq) + 2 SCN-(aq)
(yellowish brown)

When the system is at equilibrium, a blood-red solution is observed. The colour
intensity of the solution is reduced by adding distilled water.

a) If Fe(NO3)3 is added to the above system,
i. what is the disturbance applied to the reaction?

ii. predict the observation.

iii. explain the effect of the above disturbance to the equilibrium position.

b) When NaOH is added, the colour of the solution changes to yellowish brown.

i. State the change in equilibrium position.

ii. Write an equation between Fe3+ and NaOH.

iii. What is the effect on the concentration of Fe3+?

(B) The effect of temperature

2. Consider the following equilibrium system,

A(aq) + B(aq) C(aq)
(yellow) (blue)

i. A green solution is observed indicating a mixture of yellow and blue at room
temperature. What can be deduced from the observation?

ii. The above solution turns yellow in the hot water bath. Explain.

iii. State the colour of solution after it is placed in the ice bath. Explain.

iv. Predict the forward reaction as exothermic or endothermic.

SK015

Pre-Lab Module

EXPERIMENT 6
pH MEASUREMENT AND ITS APPLICATIONS

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical
chemistry. (C4, PLO4, CTPS3, MQF LO6)

Learning Outcomes:

At the end of this lesson, students will be able to:
i. Perform calculations involving pH, dissociation constant, Ka and initial concentration.

Student-Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Direction: Read over the lab manual and then answer the following question.

Introduction:
1. Define pH.

2. Give two methods to determine pH in the laboratory.

3. Explain the differences between strong acid and weak acid.

4. What is a buffer solution ?

5. Write the expression of Ka for a weak acid, HA.

SK015

Pre-Lab Module

Procedure:
1. Suggest suitable indicators for titration between

i. Nitric acid, HNO3 and potassium hydroxide, KOH

ii. Nitric acid, HNO3 and ammonia, NH3

iii. Sodium hydroxide, NaOH and hydrocyanic acid, HCN

2. State the composition of an acidic buffer solution.

3. Classify the following salt as acidic, basic or neutral salt.

Salt Type
I. NaCl
II. CH3COONa
III. NH4NO3

4. List down all precautions of the experiment.

SK015

Pre-Lab Module

Experiment 6 : Data Analysis

1. Calculate the percentage of ionisation of 0.1 M and 1.0 M acetic acid with pH 2.87 and
2.37 respectively.

2. How does the percentage of ionisation change with its concentration?

3. Refer to the pH values of acetic acid in Question 1, calculate their dissociation constant,
Ka.

CHEMISTRY 2
SK025

SK025

Pre-Lab Module

EXPERIMENT 1
RATE OF REACTION

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical and
organic chemistry. (C4, PLO4, CTPS3, MQF LOD6)

Learning Outcomes:

At the end of this lesson, students should be able to study the effect of concentration,
temperature and catalyst on the reaction rate.

Student Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Direction: Read over the lab manual and then answer the following question.

Introduction:
(A) The effect of concentration on the reaction rate

1. Define reaction rate.

2. What is the unit for reaction rate?
3. State the factors affecting rate of reaction. Explain.

SK025

Pre-Lab Module

(B) The effect of temperature and catalyst on the reaction rate
1. What iscatalyst. State the catalyst used in this experiment.

2. How is the effect of temperature on reaction rate studied in this experiment?

Procedure
List all the precautions of the experiment.

SK025

Pre-Lab Module

Experiment 1 : Data Analysis

(A) The effect of concentration on the reaction rate

1. Calculate the concentration of sodium thiosulphate (refer to Table 1.1 in lab manual)

2. A group of students carried out a study of changing concentration of X with reaction
rate. Graph ! against concentration of X is shown in Figure 1.

!
1

(s!!)


Figure 1 [x] (M)

a. What is the relationship between times of reaction with rate of reaction?

b. What does ! represent?

!

c. Deduce the relationship between the concentration of reactant with rate of
reaction.

(B) The effect of temperature and catalyst on the reaction rate

1. An experiment was conducted to determine the effect of temperature on the reaction rate.
The following data were obtained.

Temperature (°C) Time (s)
30.0 6.78
40.0 4.81
50.0 3.45
60.0 2.33

a. Using the above data, plot a graph of ! against temperature.

!

b. Predict the relationship between reaction rate and temperature.

2. Which reaction will occur faster; with catalyst or without catalyst?

3. One sunny afternoon, Aunty Mariam went grocery shopping at AEON. She left the
groceries in the car and continues to shop for hours. When she reached home, she found
that the milk that she bought had gone sour. Why do we need to keep the milk in
refrigerator to maintain its freshness?

SK025

Pre-Lab Module

EXPERIMENT 2
DETERMINING THE HEAT OF REACTION

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical and
organic chemistry. (C4, PLO4, CTPS3, MQF LOD6)

Learning Outcomes:

At the end of this lesson, students should be able to :
i. determine the heat capacity of a calorimeter
ii. determine the heat of neutralization of HCI and NaOH

Student Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Direction: Read over the lab manual and then answer the following question.

Introduction
1. What is thermochemistry?

2. The unit of measurement for enthalpy is

3. Name the device used to determine the enthalpy of reaction.

4. The specific heat capacity, c of copper metal is 0.385 J g-1C-1 while the heat capacity,
C of a calorimeter is 20.0 JC-1. Explain.

SK025

Pre-Lab Module

Procedure :
1. Why must the same calorimeter be used for both parts of experiment?

2. List down the precautions of the experiment:

SK025

Pre-Lab Module

Experiment 2 : Data Analysis

1. Given the following data,

Temperature of 50.0 mL warmer water, T2 : 37.92C

Temperature of 50.0mL cooler water, T1 : 20.91C

Temperature after mixing, Tf : 29.11C

Calculate;

a. the heat lost by the warmer water,
b. the heat lost to the cooler water,
c. the heat lost to the calorimeter,
d. the heat capacity of the calorimeter.

2. Given the following data, calculate the heat gained by the solution, the heat gained by the
calorimeter and heat of reaction:

[Assume that the density of these solutions is 1.00 g/mL]

Temperature of 50.0 mL of 1.0 M ofmonoprotic acid before mixing 21.02C
Temperature of 50.0 mL of 1.0 M of monoprotic base before mixing 21.02C
Temperature of 100.0 mL of solution after mixing 27.53C
Intial temperature of calorimeter 25.00oC
Heat capacity of calorimeter 15.56 JoC-1

SK025

Pre-Lab Module

EXPERIMENT 3
ELECTROCHEMICAL CELLS

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical and
organic chemistry. (C4, PLO4, CTPS3, MQF LOD6)

Learning Outcomes:

At the end of this lesson, students will be able to:
i. Explain how electrochemical cell is constructed.
ii. Arrange the metals in an electrochemical series.
iii. State the differences between Ered and Ecell.
iv. State the differences between Ecell andEcell
v. Determine the factors affecting the quantity of product during electrolysis.
vi. Suggest precaution steps to improve the accuracy of the data.

Student-Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Direction: Read over the lab manual and then answer the following question.

Introduction
1. What is the main difference between galvanic cell and electrolytic cell?

2. The Standard Reduction / Electrode Potential (SRP) series shows the reduction potential of
various half-cell reactions and the corresponding E reduction values listed in the order of
the most positive to the most negative values;

a) How are the Ered values determined using E0 cell measured?

SK025

Pre-Lab Module

b) Draw a diagram to show the experimental set-up to obtain the Ered values.

3. What is the difference between standard electrode potential, Ered and standard cell
potential, Ecell?

4. In this experiment, we will be constructing four galvanic cells using various half cells
with Cu2+/Cu half cells and measure the cell potential of these cells.

Ecell E0cell

The potential difference between the two The The potential difference between the
half-cells measured under non-standard two half-cells at standard condition (P= 1
conditions atm; T=25oC; concentration of the solution
used=1.0M).

a) State the conditions for the measurement of the Ecell.

b) Write an equation to show the relationship between Ecell and Ecell

SK025

Pre-Lab Module

Procedure
1. What does the voltmeter reading in this experiment represent?

2. Explain how to determine anode and cathode from the set-up of the electrolytic cell.

3. What are the precautions that need to be taken in carrying out this experiment?
Part A

Part B

SK025

Pre-Lab Module

Experiment 3 : Data Analysis
1. The table below shows the standard reduction potentials of several half cells.

Half cells E°(V)
Al3+ + 3e–→ Al(s) –1.66
I2(s) + 2e–→ 2I– (aq) +0.53
Sn4+(aq) + 2e–→ Sn2+(aq) +0.14
Fe3+(aq)+ e–→ Fe2+(aq) +0.77
Fe2+ + 2e–→ Fe(s) -0.44

Arrange the species in order of increasing strength of reducing agent. Explain your
answer.

2. State the factors that affect the quantity of product formed in electrolytic cell and explain
the law/principle applied.

3. In an electrolysis of aqueous chromium salt, a current of 0.04 A is passed for 15 min 27 s.
The mass of chromium deposited is 6.640 x 10 -3 g. Find the value of Faraday’s constant

SK025

Pre-Lab Module

EXPERIMENT 4
REACTION OF ALIPHATIC AND AROMATIC HYDROCARBONS

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical and
organic chemistry. (C4, PLO4, CTPS3, MQF LOD6)

Learning Outcomes:

At the end of this lesson, students will be able to:
i. study the chemical properties of an alkane, alkene and arene
ii. differentiate an alkane from an alkene and arene.

Student Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Introduction
1. What is hydrocarbon?

2. What is the difference between saturated and unsaturated hydrocarbons?

3. State the distinguishing feature of aromatic hydrocarbons.

4. State the type of reaction for bromination of alkane, alkene and arene.

SK025 Pre-Lab Module

Procedure
List down all precautions of the experiment:

(A) Reaction with bromine in dichloromethane
1. What is the purpose of bromine test?

2. Why must certain test tubes be fully covered with black sugar paper?

(B) Oxidation with KMnO4
What is the colour of KMnO4 solution and state its function?

SK025

Pre-Lab Module

Experiment 4 : Data Analysis

(A) Reaction with bromine in dichloromethane

1. Write the chemical equation for the bromination of ;
i. cyclopentane in the presence of sunlight.
ii. cyclopentene.

2. State the type of reaction for 1(i) and 1(ii).

3. State the function of sunlight .

(B) Oxidation with KMnO4

1. Write the chemical equation for the oxidation of the following compound with hot
acidified KMnO4.

i. cyclopentene
ii. methylbenzene

SK025

Pre-Lab Module

EXPERIMENT 5
REACTION OF HYDROXY COMPOUNDS

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical and
organic chemistry. (C4, PLO4, CTPS3, MQF LOD6)

Learning Outcomes:

At the end of this lesson, students will be able to:
i. identify classes of alcohols
ii. study the chemical properties of alcohols and phenol.

Student Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Introduction
1. Name the functional group of alcohol?

2. Complete the Table 1. Table 1 Class of alcohol
Compound Structural formula

1-pentanol
2-pentanol

2-methyl-2-butanol

Lucas Test
1. What is the function of Lucas test?

2. What is Lucas reagents?

SK025

Pre-Lab Module

3. State the expected observation for the reaction of alcohol of each following class with
Lucas reagent in Table 2.
Table 2

Class of Alcohol Observation

Primary

Secondary

Tertiary

Oxidation:

1. State the expected observation for the reaction of alcohol of each following class with
hot, acidified sodium dichromate in Table 3.

Class of Alcohol Table 3
Primary Observation

Secondary

Tertiary

Confirmatory test for phenol:
1. State the suitable reagent used as confirmatory test for phenol.

2. State the expected observation in the confirmatory test for phenol.

Procedure
List down 3 precautions during the experiment.

SK025

Pre-Lab Module

Experiment 5 : Data Analysis

1. Write the products for the reactionin following scheme.

Cyclohexanol HCl(conc), ZnCl2

Na2Cr2O7, H+
Δ

2. The reaction of alcohol A with Lucas reagent gives cloudy solution immediately. Alcohol B
turns the orange colour of hot acidified K2Cr2O7 to green. The reaction of alcohol B with
Lucas reagent gives cloudy solution within 10 minutes. Alcohol C turns the colour of hot
acidified K2Cr2O7 from orange to green while no cloudiness is observed with Lucas reagent
after 10 minutes. State the class of alcohol A, B and C. Give the example for each class of
alcohol.

SK025

Pre-Lab Module

EXPERIMENT 6
ALDEHYDES AND KETONES

Course Learning Outcome:

Solve chemistry related problems by applying basic concepts and principles in physical and
organic chemistry. (C4, PLO4, CTPS3, MQF LOD6)

Learning Outcomes:

At the end of this lesson, students will be able to:
i. name the functional group of aldehyde and ketone
ii. draw the structural formula of aldehyde and ketone

iii. list the suitable test and its used
iv. differentiate aldehyde and ketone.

Student Learning Time:

Face-to-face Non face-to-face
1 hour 1 hour

Introduction
1. Name the functional group of aldehyde and ketone?

2. Draw the general structural formula for aldehyde and ketone.

3. What is /are reagents used to differentiate aldehydes from ketones?
4. Which carbonyl compound cannot be oxidised.

SK025

Pre-Lab Module

5. Complete the Table 1. Table 1 Aldehyde/Ketone
Structural formula
Compound
Ethanal

Benzaldehyde
Propanone

6. What does the following test detect? Complete Table 2.

Identification Test Table 2 Detect
Brady’s Reagent and condition

Fehling
Tollen’s
Schift’s

Iodoform

7. State the expected observation for the reaction of carbonyl compound in Table 3.

Test Ethanal Table 3 Propanone
Brady’s Observation
Benzaldehyde

Fehling
Tollen’s
Schift’s

Iodoform

SK025 Pre-Lab Module

Procedure
List down 3 precautions during the experiment.

Experiment 6 : Data Analysis

Question 1

A, B and C are isomers with a molecular formula C4H8O. When a compound A, B and C react
with 2,4-dinitrophenylhidrazine, a yellow precipitate is formed. Compound B and C give
positive result with silver nitrate in aqueous ammonia. Deduce the structures of A, B and C.

Question 2

When compound Z with a molecular formula of C6H12 reacts with ozone followed by treatment
with zinc in dimethyl sulfide (CH3)2S, compound D and E formed. A yellow precipitate formed
when D and E reacted with 2,4-dinitrophenylhydrazine. Upon treatment with Fehling’s reagent,
only E gives brick-red precipitate. When both D and E undergo iodoform test, only D gives a pale
yellow precipitate, which on acidification yielded ethanoic acid. Deduce the structures of Z, D
and E. Write the complete equations for all the reactions involved