OCR GCSE Chemistry A (Gateway) Paper 3 Higher June 2023 question paper J248/03

1h 45m 90 marks

22 questions

Report a problem

Question

What is wrong?

Text or a picture is cut off or split Something on the paper is not here The text does not read properly The marks are wrong Something else

Goes to whoever maintains the question split. No account needed and nothing is published on this page.

Which term is a correct description of ice turning from a solid to a liquid?

A Chemical change

B Evaporation

C Freezing

D Physical change

$Question 1, shown as an image$

[1]

Answer

Which equipment is needed for distillation?

A Condenser, funnel, thermometer

B Condenser, round-bottomed flask, thermometer

C Thermometer, beaker, pH probe

D Thermometer, measuring cylinder, filter paper

$Question 2, shown as an image$

[1]

Answer

[1]

Answer

An element reacts with oxygen to form an acidic oxide.

Which area of the Periodic Table is the element from?

$Question 4, shown as an image$

[1]

Answer

The diagram shows a 3D space filling model of methane.

What are the limitations of showing methane as a 3D space filling model?

A It does not show how close together the atoms are.

B It does not show how many electrons are in a bond.

C It does not show the relative size of the atoms.

D It does not show the relative volume that the atoms take up.

$Question 5, shown as an image$

[1]

Answer

Which fraction is collected at the top of the fractional distillation column?

	Melting point range (°C)	Boiling point range (°C)
A	–70 – –60	20 – 25
B	–50 – –40	30 – 50
C	0 – 20	100 – 120
D	20 – 40	130 – 160

$Question 6, shown as an image$

[1]

Answer

How many moles are in 30 g of nitrogen, N₂?

Relative atomic mass (A_r): N = 14.0

A 0.47 mol

B 0.93 mol

C 1.07 mol

D 2.14 mol

$Question 7, shown as an image$

[1]

Answer

Calcium phosphate contains the ions Ca²⁺ and PO₄^3–.

What is the formula for calcium phosphate?

A CaPO₄

B Ca₂PO₄

C Ca₂(PO₄)₃

D Ca₃(PO₄)₂

$Question 8, shown as an image$

[1]

Answer

Which statement about an oxidising agent is correct?

A It gains oxygen in a reaction.

B It is oxidised in a reaction.

C It is reduced in a reaction.

D It loses electrons in a reaction.

$Question 9, shown as an image$

[1]

Answer

A solution of hydrochloric acid is pH 2. The acid solution is diluted, and the pH is now 3.

By what factor is the acid solution diluted?

A 5

B 10

C 100

D 1000

$Question 10, shown as an image$

[1]

Answer

Which row explains how the structure of graphene is different from the structure of graphite?

	Graphene	Graphite
A	3 covalent bonds to each carbon atom	4 covalent bonds to each carbon atom
B	covalent bonds in 3D	covalent bonds in one 2D plane
C	intermolecular forces	no intermolecular forces
D	one layer	many layers

$Question 11, shown as an image$

[1]

Answer

The empirical formula of a compound is CH₂O.

The relative formula mass of the compound is 180.0.

What is the molecular formula of the compound?

Relative atomic mass (A_r): C = 12.0 H = 1.0 O = 16.0

A C₄H₈O₄

B C₅H₁₀O₅

C C₆H₁₂O₆

D C₇H₁₄O₇

$Question 12, shown as an image$

[1]

Answer

Which diagram represents a strong, dilute acid?

$Question 13, shown as an image$

[1]

Answer

What is the correct balanced equation for the combustion of hexane, C₆H₁₄?

$Question 14, shown as an image$

[1]

Answer

A student investigates some samples using gas chromatography.

The student also measures the melting point of each sample.

Which results should the student expect from a pure sample?

	Gas chromatogram	Melting point (°C)
A	3 peaks	123–127
B	1 peak	123–127
C	2 peaks	125
D	1 peak	125

$Question 15, shown as an image$

[1]

Answer

A scientist is studying acids and alkalis.

(a)

[1]

Answer

(b)

The scientist reacts sulfuric acid with insoluble magnesium carbonate, MgCO₃.

They repeat the experiment two more times.

The table shows their results.

	Experiment 1	Experiment 2	Experiment 3
Mass of magnesium sulfate, MgSO₄, produced (g)	4.37	4.31	4.38
Mass of magnesium carbonate, MgCO₃, remaining (g)	1.33	1.38	1.32

(b)(i)

Calculate the mean mass of magnesium sulfate, MgSO₄, made.

Give your answer to 3 significant figures.

[3]

Answer

(b)(ii)

Complete the balanced symbol equation for the reaction.

Include state symbols.

$Question 16, shown as an image$

[2]

Answer

(b)(iii)

How does the scientist remove the unreacted solid magnesium carbonate, MgCO₃(s)?

[1]

Answer

(b)(iv)

How does the scientist obtain pure dry magnesium sulfate crystals from magnesium sulfate solution?

[1]

Answer

(a)

A student does an experiment to find out the temperature change of the reaction between an acid and an alkali.

The diagram shows the student’s experiment.

(a)(i)

Label the equipment in the diagram.

[3]

Answer

(a)(ii)

Suggest one change the student can make so that the temperature change is measured more accurately. Use the diagram.

[1]

Answer

(b)

(b)(i)

Plot the results from the table on the grid.

[2]

Answer

(b)(ii)

Describe what happens to the temperature measured as the acid is added.

[2]

Answer

(b)(iii)

The reaction is exothermic.

Explain how you can tell this from the student’s results.

[1]

Answer

(c)

The activation energy for the student’s reaction is 132 kJ / mol.

Complete the sentence to state the meaning of activation energy.

Activation energy is the minimum........

[1]

Answer

(a)

The model of the atom has developed over time.

Describe the experiment and results that Rutherford, Geiger, and Marsden used to determine that an atom has a nucleus.

[3]

Answer

(b)

[2]

Answer

(c)

Complete the dot and cross diagram to show the bonding in carbon dioxide, CO₂.

You only need to show the outer shell electrons.

[2]

Answer

(d)(i)

At –78 °C, and 0.1 MPa pressure, carbon dioxide changes state from a solid to a gas.

Changing state from a solid to a gas is called subliming.

Describe what happens to the movement and arrangement of the particles when a solid turns into a gas. Use the particle model.

[3]

Answer

(d)(ii)

Carbon dioxide can be a liquid at different pressures and temperatures.

Pressure (MPa)	Melting point (°C)	Boiling point (°C)	Sublimation point (°C)
0.1			–78
1.0	–56	–40

State a temperature and a pressure at which carbon dioxide is a liquid.

Explain your answer.

Temperature........ °C Pressure........ MPa

Reason........

[3]

Answer

A scientist wants to make copper using electrolysis. They consider two different electrolysis experiments using inert electrodes as shown in the table.

	Experiment 1	Experiment 2
Electrolyte	molten copper chloride	copper sulfate solution
Electrode the scientist collects product from	anode	cathode

(a)

* Predict and explain what will be made at the electrode the scientist collects the product from in each experiment.

Determine which experiment the scientist should use to make copper.

[6]

Answer

(b)

Another scientist investigates the electrolysis of lead bromide.

The diagram shows their experiment.

The experiment does not make any lead.

State two changes the scientist should make so that lead is made.

[2]

Answer

(c)

Complete the balanced half equation for the production of bromine from bromide ions.

$Question 19, shown as an image$

[2]

Answer

(a)

A scientist has a sample of seawater. The sample contains sand, water and salt.

The scientist wants to collect pure samples of:

• sand

• water

• salt.

Describe a method the scientist could use to separate and collect the sand, water and salt.

You can include labelled diagrams in your answer.

[4]

Answer

(b)

The salt collected is sodium chloride.

Complete the ball and stick model by labelling the sodium ions and the chloride ions.

[2]

Answer

(c)

Seawater can contain isotopes of sulfur.

(c)(i)

Draw three lines to connect each isotope with its correct description.

[2]

Answer

(c)(ii)

Some of this sulfur in seawater is in the form of magnesium sulfate, MgSO₄.

What is the relative formula mass of a sample of magnesium sulfate, MgSO₄, where all of the sulfur atoms are the isotope sulfur-33?

Relative atomic mass (A_r): O = 16.0 Mg = 24.3

[2]

Answer

(c)(iii)

A scientist wants to separate magnesium sulfate from other compounds using thin layer chromatography.

The spot does not move from the start line on the chromatogram.

State what the scientist should change so that magnesium sulfate is separated from the other compounds.

[1]

Answer

(c)(iv)

Explain why magnesium sulfate has a high melting point.

[2]

Answer

Table 21.1 shows information about four different substances.

Table 21.1

Substance	Melting point (°C)	Appearance	Electrical conductor?
1	1085	shiny solid	yes
2	770	white crystals	yes when dissolved in water
3	120	flexible solid	no
4	78	white crystals	no

(a)

Which of the substances is a polymer?

Explain your answer.

Substance........

Reason........

[3]

Answer

(b)

Fig. 21.1 shows two different polymer structures.

Fig. 21.1

Explain why polymers without cross-links can stretch more than polymers with cross-links.

[2]

Answer

(c)

Fig. 21.2 shows an electrical cable.

Fig. 21.2

Which substance from Table 21.1 would be best to use to make each part of the electrical cable?

Explain your answers.

Part A........

Reason........

Part B........

Reason........

[3]

Answer

Magnesium nitrate decomposes when heated to form magnesium oxide.

$Question 22, shown as an image$

(a)(i)

Calculate the mass of oxygen made when 0.45 moles of magnesium nitrate decomposes.

Relative atomic mass (A_r): O = 16.0.

[3]

Answer

(a)(ii)

Calculate how many molecules of nitrogen dioxide, NO₂, are produced from 0.45 moles of magnesium nitrate.

The Avogadro constant is 6.02 maths symbol 10²³.

Give your answer to 3 significant figures.

Number of molecules of NO₂ =........

[3]

Answer

(b)

The decomposition of magnesium nitrate is an endothermic reaction.

Complete the reaction profile for an endothermic reaction.

Include the labels:

• products

• activation energy

• energy change of reaction.

[4]

Answer

(c)

Magnesium nitrate is an ionic compound.

(c)(i)

Explain why magnesium forms Mg²⁺ ions. (i)

[1]

Answer

(c)(ii)

A solution containing magnesium ions reacts with a solution containing hydroxide ions.

Solid magnesium hydroxide is made.

Write the balanced ionic equation for this reaction.

[2]

Answer

The paper as printed

Spotted a mistake on this page?Report a problem

OCR J248 · Paper 3

Question 1

Question 2

Question 3

Question 4

Question 5

Question 6

Question 7

Question 8

Question 9

Question 10

Question 11

Question 12

Question 13

Question 14

Question 15

Question 16

Question 17

Question 18

Question 19

Question 20

Question 21

Question 22