ChemistryKS4 Quantitative

Chemistry Homework Booklet

Name: _________________________________________Class: _________________________________________Teacher: _______________________________________

Read the Qu01 sections on your knowledge organisers before you begin.

Comprehension Task Iron has three oxides with the following formulae:

Iron (II) Oxide, FeO Iron (III) Oxide, Fe2O3

Iron (II,III) Oxide, Fe3O4

Calculate the relative formula mass of each oxide of Iron.Page 1 of 25

Homework Task Due Date

Teacher Signature

Qu01 Relative Mass and MolesQu02 Equations and CalculationsQu03 From masses to balanced equationsQu04 The yield of a chemical reactionQu05 Atom economyQu06 Expressing concentrationQu07 Titrations RPQu08 Titration CalculationsQu09 Volumes of Gases

Qu 01

Relative Mass and Moles – I should know… R A G

How to calculate the relative atomic mass of an element using the proportions of isotopes

How to calculate relative formula mass of an element [H] How to calculate the number of moles (or mass) of a

substance, using its mass (or number of moles) and relative formula mass

[H] What Avogadro’s constant tells us about moles

Qu01 Relative Mass and Moles Exam Question Practise

Q1.

(a)  What is the relative formula mass (Mr) of titanium dioxide, TiO2?

Relative atomic masses (Ar):  O = 16  Ti = 48

Tick one box. 

64

80

128

768

(1)

Comprehension Task Iron has three oxides with the following formulae:

Iron (II) Oxide, FeO Iron (III) Oxide, Fe2O3

Iron (II,III) Oxide, Fe3O4

Calculate the relative formula mass of each oxide of Iron.

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(b)     How many atoms are present in one mole of fluorine atoms?

Tick (✔) one box. 

2.03 × 1026

2.06 × 1023

6.02 × 1023

6.02 × 1026

(1)

(c)     An element has three isotopes.

The table shows the mass numbers and percentage of each isotope. 

  Isotope 1 Isotope 2 Isotope 3

Mass number 24 25 26

Percentage (%) 78.6 10.1 11.3

Calculate the relative atomic mass (Ar) of the element.

Give your answer to 3 significant figures.(2)

(d)    Complete the table below to show the number of atoms of carbon and oxygen in the formula of zinc carbonate, ZnO3

 

Element Number of atoms in

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the formula ZnCO3

zinc, Zn 1

carbon, C

oxygen, O

(2)

(e)     When 125 g zinc carbonate is heated, 81 g zinc oxide is produced.

Calculate the mass of carbon dioxide produced.(1)

(f)     Calculate the relative formula mass (Mr) of the hydrocarbon in the diagram above.

Relative atomic masses (Ar): H = 1 C = 12(2)

(g)     Calculate the relative formula mass (Mr) of aluminium sulfate Al2(SO4)3

Relative atomic masses (Ar): oxygen = 16; aluminium = 27; sulfur = 32(2)

(h)     Calculate the relative formula mass (Mr) of lead nitrate Pb(NO3)2

Relative atomic masses (Ar): N = 14 O = 16 Pb = 207(2)

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Qu 02

Equations and Calculations – I should know… R A G

[H] What balanced equations tell you about chemical reactions

[H] How to use balanced equations to calculate masses of reactants and products

Qu 03

From Masses to Balanced Equations – I should know… R A G

[H] How to work out a balanced equation using the masses of the reactants and products

[H] Why a limiting reactant affects the amount of a product that can be obtained from a reaction

Read the Qu02 and Qu03 and keyword sections on your knowledge organisers before you begin.

Comprehension Task

The image above shows copper reacting with oxygen. Balance the equation below so that it matches

Page 5 of 25

TYPE HERE

Qu02/Qu03 Balanced Equations and Calculations Exam Question Practise

Q1.

(a)  In industry, methanol is produced by reacting carbon monoxide with hydrogen.

The equation for the reaction is:

CO(g) + 2H2(g) ⇌ CH3OH(g)

  How many moles of carbon monoxide react completely with 4.0 × 103 moles of hydrogen?

Tick one box. 

1.0 × 103 moles

2.0 × 103 moles

Comprehension Task

The image above shows copper reacting with oxygen. Balance the equation below so that it matches

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4.0 × 103 moles

8.0 × 103 moles

(1)

(b)    Nitrogen and hydrogen are passed over iron to produce ammonia in the Haber Process.

Balance the equation for the reaction.

        N2     +         H2      →          NH3

(1)

(c)     Some iron ores contain iron oxide (Fe2O3).

Complete and balance the equation for a reaction to produce iron from iron oxide.

_____ Fe2O3     +     _____ C     →     ___________     +     _____ CO2

(2)

(d)  Nitrogen dioxide reacts to produce nitrogen and oxygen in catalytic converters.

Complete the equation for this reaction.

The equation should be balanced.

____ NO2 (g)  ⟶ ____________ + ____ O2 (g)(2)

(e)     The reaction of hydrogen with carbon monoxide is shown below:

Balance the equation for the reaction.

H2  +  CO  ⟶  C6H14  +  H2O(1)

Q2.    A student wanted to make 11.0 g of copper chloride.

The equation for the reaction is:

                             CuCO3 + 2HCl  →  CuCl2 + H2O + CO2

Relative atomic masses, Ar: H = 1; C = 12; O = 16; Cl = 35.5; Cu = 63.5

Calculate the mass of copper carbonate the student should react with dilute hydrochloric acid to make 11.0 g of copper chloride.

You should show your working

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(4)

Q3.  In a reaction, 40 kg of titanium chloride was added to 20 kg of sodium.

The equation for the reaction is:

TiCl4 + 4 Na ⟶ Ti + 4 NaCl

Relative atomic masses (Ar): Na = 23 Cl = 35.5 Ti = 48

Explain why titanium chloride is the limiting reactant.

You must show your working.(4)

Qu 04

Yield of a Chemical Reaction. [CHEMISTRY ONLY] – I should know… R A G

What is meant by the yield of a chemical reaction What factors affect the yield How to calculate theoretical yield of a reaction How to calculate percentage yield of a reaction

Read the Qu 04 sections on your knowledge organisers before you begin.

Comprehension Task Percentage yield of a chemical reaction is given by the following formula:

Percentage yield = (actual yield ÷ theoretical yield) x 100

A student carried out a reaction to produce a chemical. She calculated the yield for the reaction as 106%

Explain why this yield is incorrect. Page 8 of 25

Qu 04 Yield Exam Question Practise

Q1.

(a)  A company calculates that 500 g of titanium dioxide should produce 1.2 kg of titanium chloride.

However, the company finds that 500 g of titanium dioxide only produces 900 g of titanium chloride.

Calculate the percentage yield.(2)

(b)  For a reaction the percentage yield was 92.3%

Comprehension Task Percentage yield of a chemical reaction is given by the following formula:

Percentage yield = (actual yield ÷ theoretical yield) x 100

A student carried out a reaction to produce a chemical. She calculated the yield for the reaction as 106%

Explain why this yield is incorrect.

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The theoretical maximum mass of titanium produced in this batch was 13.5 kg.

Calculate the actual mass of titanium produced.(2)

(c)     A student tried to make 11.0 g of copper chloride.

The percentage yield of copper chloride was 79.1 %.

Calculate the mass of copper chloride the student actually produced.(2)

Q2.

(a)    Calculate the minimum mass of zinc that needs to be added to 0.500 g of iodine so that the iodine fully reacts.

The equation for the reaction is:

Zn + I2 ⟶ ZnI2

Relative atomic masses (Mr): Zn = 65  I = 127(3)

Page 10 of 25

A scientist obtains 12.5 g of zinc iodide using the above reaction

The percentage yield in this reaction is 92.0%.

(b)     What is the maximum theoretical mass of zinc iodide produced in this reaction?(3)

(c)     Suggest one reason why the percentage yield in this reaction is not 100%.(1)

  Qu 05

Atom Economy [CHEMISTRY ONLY] – I should know…

How to calculate the atom economy of a reaction with respect to a desired product

Why atom economy is important in industrial processes

Read the Qu 05 sections on your knowledge organisers before you begin.

Comprehension Task The image below shows 2 ways of producing 1-phenylethanol, which is an important chemical feedstock. It is used to make styrene, the monomer for polystyrene. (you do not need to know about this structure for your GCSE)

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Qu05 Atom Economy Exam Question Practise

Q1.

(a) The percentage atom economy for a reaction is calculated using:

 

The equation for the reaction of copper carbonate and sulfuric acid is:

CuCO3 + H2SO4 → CuSO4 + H2O + CO2

Relative formula masses : CuCO3 = 123.5; H2SO4 = 98.0; CuSO4 = 159.5

Comprehension Task The image below shows 2 ways of producing 1-phenylethanol, which is an important chemical feedstock. It is used to make styrene, the monomer for polystyrene. (you do not need to know about this structure for your GCSE)

Page 12 of 25

Calculate the percentage atom economy for making copper sulfate from copper carbonate.

(3)

(b)  An equation for a reaction is:

NiO + C ⟶ Ni + CO

Calculate the percentage atom economy for the reaction to produce nickel.

Relative atomic masses (Ar): C = 12  Ni = 59

Relative formula mass (Mr): NiO = 75

Give your answer to 3 significant figures.(3)

Q2.

Zinc sulfate can be made by two methods.

The equations for the two methods are:

Method 1: ZnO + H2SO4 ⟶ ZnSO4 + H2O

Method 2: ZnCO3 + H2SO4 ⟶ ZnSO4 + H2O + CO2

(a)     Calculate the percentage atom economy for making zinc sulfate in Method 1.

Use the equation:

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percentage atom economy =

 

Give your answer to 3 significant figures.

Relative formula masses (Mr):  ZnO = 81  H2SO4 = 98  ZnSO4 = 161(3)

(b)     Method 1 gives a higher percentage atom economy for making zinc sulfate than Method 2.

Give a reason why it is important to use a reaction with a high atom economy.(1)

Q3.

(a)     Look at the equations for the two reactions:

   Reaction 1        CuCO3(s) + 2HCl(aq)  →  CuCl2(aq) + H2O(l) + CO2(g)

   Reaction 2             CuO(s) + 2HCl(aq)  →  CuCl2(aq) + H2O(l)

Reactive formula masses: CuO = 79.5; HCl = 36.5; CuCl2 = 134.5; H2O = 18

The percentage atom economy for a reaction is calculated using:

      

Calculate the percentage atom economy for Reaction 2.(3)

(b)     The atom economy for Reaction 1 is 68.45 %.Compare the atom economies of the two reactions for making copper chloride.

Give a reason for the difference.(1)

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Qu 06

Expressing Concentration – I should know… R A G

How concentrations can be expressed in grams per dm3 (g/dm3) or moles per dm3 (mol/dm3)

[H] How mass (in g) of solute and volume (in dm3) of solution relate to the concentration of the solution

Qu06 Concentrations Exam Question Practise

Q1.

(a)  A solution of NaOH had a concentration of 40 g/dm3

What mass of NaOH would there be in 250 cm3 of the solution?(2)

Read the Qu06 sections on your knowledge organisers before you begin.

Comprehension Task Which of the following solutions has the highest concentration?

Explain why it has the higher concentration in terms of particles

10 grams of salt in 250cm3 of solution 20 grams of salt in 2dm3 of solution

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(b)     A student uses 50 cm 3 of a zinc sulfate solution of 80 g/dm 3

What mass of zinc sulfate is dissolved in 50 cm 3 of this zinc sulfate solution?(2)

(c)  Calculate the mass of sodium hydroxide in 30.0 cm3 of a 0.105 mol/dm3 solution.

Relative formula mass (Mr): NaOH = 40(2)

(d)     A sodium hydroxide solution has a concentration of 0.18 mol / dm3.

Relative formula mass (Mr) of NaOH = 40

Calculate the mass of sodium hydroxide in 20 cm3 of this solution.(2)

(e)      A scientist makes a solution of zinc iodide with a concentration of 0.100 mol / dm3

Calculate the mass of zinc iodide (ZnI2) required to make 250 cm3 of this solution.

Relative atomic masses (Ar): Zn = 65 I = 127(3)

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Qu 07

Titrations (REQUIRED PRACTICAL) [CHEMISTRY ONLY] – I should know…

R A G

How to accurately measure the volumes (in dm3) of two solutions that completely react together

How to determine the end point of a neutralisation reaction using the titration method

Qu 08 Titration Calculations [CHEMISTRY ONLY] – I should know… R A G

[H] How to calculate the number of moles (in mol) or mass (in g) of a solute in a given volume (in dm3) of solution, if the

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concentration (in mol/dm3) is known. [H] How to calculate the amount (in moles) of acid or alkali

needed in a neutralisation reaction [H] How to calculate an unknown concentration (in mol/dm3)

from reacting volumes (in dm3) of two solutions, if the concentration (in mol/dm3) of one of the solutions is known.

Qu07 and Qu08 Titrations Exam Question Practise

Q1.

(a)     The student carried out five titrations. Her results are shown in the table below. 

Titration 1 Titration 2 Titration 3 Titration 4 Titration 5

Read the Qu07 and Qu08 sections on your knowledge organisers before you begin.

Comprehension Task Sodium hydroxide neutralises sulfuric acid.

     A student used a pipette to add 25.0 cm3 of sodium hydroxide of unknown concentration to a conical flask.

The student carried out a titration to find out the volume of 0.100 mol / dm3 sulfuric acid needed to neutralise the sodium hydroxide.

Describe how the student would complete the titration.

You should name a suitable indicator and give the colour change that would be seen.

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Volume of 0.100 mol / dm3 sulfuric acid in cm3

27.40 28.15 27.05 27.15 27.15

Concordant results are within 0.10 cm3 of each other.

Use the student’s concordant results to work out the mean volume of 0.100 mol / dm3 sulfuric acid added.

(2)

(b)     The equation for the reaction is:

                               2NaOH + H2SO4  →  Na2SO4 + 2H2O

Calculate the concentration of the sodium hydroxide.

Give your answer to three significant figures.(4)

Q2.

A student titrated citric acid with sodium hydroxide solution.

This is the method used.

1. Pipette 25.0 cm3 of sodium hydroxide solution into a conical flask.

Page 19 of 25

2. Add a few drops of thymol blue indicator to the sodium hydroxide solution.

    Thymol blue is blue in alkali and yellow in acid.

3. Add citric acid solution from a burette until the end-point was reached.

(a)     Explain what would happen at the end-point of this titration.

Refer to the acid, the alkali and the indicator in your answer.(3)

(b)     Explain why a pipette is used to measure the sodium hydroxide solution but a burette is used to measure the citric acid solution

(2)

(c)     The table shows the student’s results. 

  Titration 1 Titration 2 Titration 3 Titration 4 Titration 5

Volume of citric acid solution in cm3

13.50 12.10 11.10 12.15 12.15

The equation for the reaction is:

C6H8O7 + 3 NaOH ⟶ C6H5O7Na3 + 3 H2O

The concentration of the sodium hydroxide was 0.102 mol / dm 3

Concordant results are those within 0.10 cm 3 of each other.

Calculate the concentration of the citric acid in mol / dm 3

Use only the concordant results from the table in your calculation.

You must show your working.(5)

Page 20 of 25

Q3.

A student titrated 25.0 cm3 portions of dilute sulfuric acid with a 0.105 mol/dm3 sodium hydroxide solution.

  The table below shows the student’s results. 

  Titration1

Titration2

Titration3

Titration4

Titration5

Volume of sodium hydroxide solution in cm3 23.50 21.10 22.10 22.15 22.15

The equation for the reaction is:

2 NaOH + H2SO4 ⟶ Na2SO4 + 2 H2O

Calculate the concentration of the sulfuric acid in mol/dm3

Use only the student’s concordant results.

Concordant results are those within 0.10 cm3 of each other.(5)

Qu 09 Volumes of Gases [CHEMISTRY ONLY] – I should know… R A G

[H] How to calculate the volume (in dm3) of a gas at room temperature and pressure from its mass (in g) and relative formula mass

[H] How to calculate volumes (in dm3) of gaseous reactants

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and products from a balanced equation and a given volume (in dm3) of a gaseous reactant or product

Qu09 Gas Volumes Exam Question Practise

Q1.

Read the Qu09 sections on your knowledge organisers before you begin.

Comprehension Task 44 grams of CO2 and 32 grams of O2 occupy the same volume.

Explain why, and how it is possible when the gases have different sized molecules.

Page 22 of 25

A student measured the volumes of gases collected every minute for 20 minutes.

The graph below shows the student’s results. 

 

Calculate the amount in moles of chlorine collected after 20 minutes.

Use the graph above

The volume of one mole of any gas at room temperature and pressure is 24.0 dm3

Give your answer in standard form.(3)

Q2.(a) Sodium carbonate reacts with dilute hydrochloric acid:

                   Na2CO3 + 2HCl  →  2NaCl + H2O + CO2

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     The carbon dioxide was collected at room temperature and pressure.The volume of one mole of any gas at room temperature and pressure is 24.0 dm3.

How many moles of carbon dioxide is 95.0 cm3?

Give your answer to three significant figures.(2)

(b) Calculate what mass of Sodium Carbonate (Na2CO3) was needed to produce 0.95cm3 of carbon dioxide

Relative atomic masses, Ar: Na = 23; C = 12; O = 16; (3)

Q3.Air bags are used to protect the passengers in a car during an accident. When the crash sensor detects an impact it causes a mixture of chemicals to be heated to a high temperature. Reactions take place which produce nitrogen gas. The nitrogen fills the air bag.

 

     The mixture of chemicals contains sodium azide (NaN3) which decomposes on heating to form sodium and nitrogen.

2NaN3       →       2Na       +       3N2

A typical air bag contains 130 g of sodium azide.

Calculate the volume of nitrogen that would be produced when 130 g of sodium azide decomposes.

Relative atomic masses (Ar): N = 14; Na = 23

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The volume of one mole of any gas at room temperature and pressure is 24.0 dm3.

Mass of nitrogen = ___________________ g (4)

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