OCR GCSE Chemistry A (Gateway) Paper 2 Foundation November 2020 question paper J248/02

1h 45m 90 marks

24 questions

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Iron is a metal that rusts.

What conditions are needed for the rusting of iron?

A Air and an acid

B Air and salt

C Air and water

D Water and salt

$Question 1, shown as an image$

[1]

Answer

A student adds a few drops of sodium hydroxide solution to an unknown solution and a blue precipitate is made.

Which metal ion is present in the original solution?

A Calcium

B Copper(II)

C Iron(II)

D Iron(III)

$Question 2, shown as an image$

[1]

Answer

Look at the equation for the Haber process.

$Question 3, shown as an image$

A A reaction that involves a catalyst.

B A reaction that is exothermic.

C A reaction with 100% atom economy.

D A reversible reaction.

$Question 3, shown as an image$

[1]

Answer

Brass is an alloy.

What are the main metals in brass?

A Aluminium and copper

B Copper and iron

C Copper and tin

D Copper and zinc

$Question 4, shown as an image$

[1]

Answer

Which of the following are three of the essential elements needed by plants?

A Carbon, nitrogen, oxygen

B Hydrogen, potassium, phosphorus

C Nitrogen, oxygen, potassium

D Nitrogen, phosphorus, potassium

$Question 5, shown as an image$

[1]

Answer

What happens to the potential difference of a chemical cell once the reactants are used up?

A It decreases

B It increases

C It starts and finishes at 0 V

D It stays the same

$Question 6, shown as an image$

[1]

Answer

Crude oil is separated into fractions by fractional distillation.

Look at the diagram of the fractions made in fractional distillation.

Which of these fractions has the lowest boiling point?

A Bitumen

B Diesel oil

C Gases

D Petrol

$Question 7, shown as an image$

[1]

Answer

DNA molecules are polymers.

What is the name of the monomers that make up DNA molecules?

A Amino acids

B Carbohydrates

C Nucleotides

D Proteins

$Question 8, shown as an image$

[1]

Answer

The table shows the stages in a flame test.

Stage	Process
1	Dip a nichrome wire loop into the test solution.
2	Observe and record the flame colour.
3	Clean a nichrome wire loop with hydrochloric acid, then rinse with distilled water.
4	Hold the nichrome wire loop in the edge of a roaring blue flame.

Which is the correct order for the stages in a flame test?

A 1, 4, 2, 3

B 1, 4, 3, 2

C 3, 1, 4, 2

D 3, 4, 1, 2

$Question 9, shown as an image$

[1]

Answer

Which of the following are the first four members of the homologous series of alcohols ?

A CH₄, C₂H₆, C₃H₈, C₄H₁₀

B CH₃OH, C₂H₅OH, C₃H₇OH, C₄H₉OH

C HCOOH, CH₃COOH, C₂H₅COOH, C₃H₇COOH

D C₂H₄, C₃H₆, C₄H₈, C₅H₁₀

$Question 10, shown as an image$

[1]

Answer

A student investigates the reaction between zinc and dilute sulfuric acid.

He measures the time taken to collect 50 cm³ of hydrogen gas. This time is 65 seconds.

The student investigates four substances which are possible catalysts for the reaction.

Which substance, A, B, C or D, is a catalyst for the reaction?

$Question 11, shown as an image$

[1]

Answer

Ethene, C₂H₄, reacts with bromine, Br₂, in an addition reaction.

Which is the balanced symbol equation for this reaction?

$Question 12, shown as an image$

[1]

Answer

Zinc, Zn, reacts with copper sulfate solution, CuSO₄.

$Question 13, shown as an image$

What type of reaction is this?

A Combustion

B Displacement

C Neutralisation

D Thermal decomposition

$Question 13, shown as an image$

[1]

Answer

A student investigates the decomposition of hydrogen peroxide.

$Question 14, shown as an image$

0.2 g of oxygen gas is produced in the reaction.

The student uses 0.5 g of manganese(IV) oxide as a catalyst in the reaction.

How much manganese(IV) oxide remains at the end of the reaction?

A 0.2 g

B 0.3 g

C 0.5 g

D 0.7 g

$Question 14, shown as an image$

[1]

Answer

Hydrogen gas, H₂, reacts with oxygen gas, O₂, to make water, H₂O.

$Question 15, shown as an image$

What is the atom economy for this reaction?

M_r: H₂ = 2, O₂ = 32, H₂O = 18.

A 50%

B 53%

C 89%

D 100%

$Question 15, shown as an image$

[1]

Answer

(a)

Complete the table. Use ideas about trends down a Group to help you.

[2]

Answer

(b)

In the table, the Group 7 elements are listed in order of reactivity.

The equations show a displacement reaction of Group 7 elements.

$Question 16, shown as an image$

(b)(i)

Complete the word equation.

$Question 16, shown as an image$

[1]

Answer

(b)(ii)

There is no reaction between iodine and sodium bromide.

Explain why.

[1]

Answer

(b)(iii)

Chlorine reacts with sodium iodide. Sodium chloride and iodine are made.

Write the balanced symbol equation for this reaction.

[2]

Answer

(c)

Group 1 is another group of elements in the Periodic Table.

(c)(i)

Potassium is a Group 1 metal.

Potassium is stored under oil because it is very reactive.

What does the oil stop the potassium reacting with?

[1]

Answer

(c)(ii)

Sodium is another Group 1 metal.

Sodium reacts in a similar way to potassium.

Explain why.

Use ideas about atomic structure in your answer.

[1]

Answer

A student investigates a white solid.

Table 17.1 shows some of the results of the tests that the student does.

(a)

Which ion is shown to be in the white solid by the result of Test 1 ?

[1]

Answer

(b)(i)

Which ion is shown to be in the white solid by the result of Test 2 ?

[1]

Answer

(b)(ii)

The gas given off in Test 2 is carbon dioxide, CO₂.

What is the expected result with limewater?

[1]

Answer

(c)

The student reacts some metals with different salt solutions.

Table 17.2 shows her results.

(c)(i)

What colour is iron sulfate solution?

[1]

Answer

(c)(ii)

Write down the order of reactivity of the four metals copper, iron, magnesium and zinc.

Use Table 17.2 to help you.

[2]

Answer

(c)(iii)

Magnesium reacts with copper sulfate, CuSO₄.

Magnesium sulfate, MgSO₄, and copper are made.

Write the balanced symbol equation for this reaction.

[1]

Answer

(a)

Another student also investigates the rate of reaction between dilute hydrochloric acid and magnesium carbonate.

Fig. 18.2 shows diagrams of some of the apparatus he uses.

The student also wants to find out how the concentration of the acid changes the rate of reaction.

Describe the method he follows using the apparatus in Fig. 18.2.

Include a labelled diagram of the set-up of the apparatus he uses.

[4]

Answer

(b)

(b)(i)

Plot a graph of the results on the grid. Draw a line of best fit.

[3]

Answer

(b)(ii)

What is the reaction time at 25 °C ?

[1]

Answer

(b)(iii)

What happens to the rate of reaction as the temperature increases?

[1]

Answer

(b)(iv)

Explain your answer to (b)(iii). Include ideas about collisions between particles in your answer.

[2]

Answer

Fractional distillation separates crude oil into useful fractions.

Look at the table.

It shows the percentage of each fraction made from crude oil. It also shows the percentage of each fraction needed for everyday uses.

Fraction	Percentage made by fractional distillation	Percentage needed for everyday uses
Gases	4	11
Petrol	11	22
Naphtha	10	18
Paraffin	12	20
Fuel oil	22	10
Waxes and tar	23	4

(a)(i)

[1]

Answer

(a)(ii)

[1]

Answer

(b)

Cracking changes large hydrocarbon molecules into smaller hydrocarbon molecules.

(b)(i)

One of the conditions needed for cracking is a high pressure.

Write down one other condition needed.

[1]

Answer

(b)(ii)

Cracking is a very useful reaction.

Explain why.

Use information from the table in your answer.

[2]

Answer

(c)

In 2008 the USA produced 4 900 000 barrels of crude oil per day. In 2019 this had increased to 11 000 000 barrels of crude oil per day.

Calculate the percentage increase in the number of barrels of crude oil produced per day from 2008 to 2019. Use the formula: percentage increase = $fraction$ maths symbol 100 Give your answer to 2 decimal places.

[3]

Answer

A student neutralises an alkali with an acid in a titration experiment.

(a)

Complete the word equation for the reaction of an acid with an alkali.

$Question 20, shown as an image$

[2]

Answer

(b)

Look at the student’s method for her experiment.

• Measure 25.0 cm³ of alkali solution into a conical flask using a pipette.

• Add a few drops of universal indicator to the alkali solution.

• Fill the burette to above the 0.0 cm³ line with acid.

• Quickly add the acid to alkali until the indicator changes colour.

• Repeat the experiment until consistent results are obtained.

Describe and explain one improvement the student should make to her method to get a more accurate titration result.

[2]

Answer

(c)

The student repeats the experiment three times.

Look at the student’s results.

Titration number	1	2	3
Volume of acid (cm³)	25.75	23.60	23.70

Calculate the accurate volume of the acid that reacts with the alkali.

[2]

Answer

This question is about the Earth’s atmosphere.

The Earth’s early atmosphere contained mostly carbon dioxide gas.

The Earth’s atmosphere today contains about 0.04% carbon dioxide.

(a)

Explain why the amount of carbon dioxide in the atmosphere today has decreased from the early atmosphere.

[1]

Answer

(b)

[1]

Answer

(c)

Many scientists believe that increasing amounts of carbon dioxide in the Earth’s atmosphere are causing global warming.

(c)(i)

Write down one way that carbon dioxide is released into the atmosphere.

[1]

Answer

(c)(ii)

Write down one way to reduce the amount of carbon dioxide that is released into the atmosphere.

[1]

Answer

(d)

Sulfur dioxide is a pollutant found in many large cities.

Sulfur dioxide is an acidic gas.

(d)(i)

Suggest a value for the pH of sulfur dioxide.

[1]

Answer

(d)(ii)

Describe one problem caused by sulfur dioxide.

[1]

Answer

(a)

Ethane and propane are both members of the homologous series called the alkanes.

Write down two reasons why ethane and propane are members of the same homologous series.

[2]

Answer

(b)

Many ethene molecules react together to form the polymer poly(ethene).

This reaction is called polymerisation.

(b)(i)

Why do ethene molecules undergo polymerisation but ethane molecules do not?

[1]

Answer

(b)(ii)

Complete the diagram to show the displayed formula of poly(ethene).

[2]

Answer

(c)

* Propane gas is used as a fuel for cooking and heating in caravans.

Incomplete combustion of propane can occur if the campers do not take sensible precautions.

Describe how incomplete combustion of hydrocarbons such as propane happens and the problems it can cause for campers.

Include a balanced symbol equation in your answer.

[6]

Answer

This question is about the properties of materials.

(a)

Look at the table. It shows information about two materials.

	Polymer	Metal
Melting Point (°C)	100–260	1100
Density (kg / m³)	940	8940
Relative electrical conductivity (10 = good, 1 = poor)	2	10
Flexibility	high	high

Electrical cables are made of metal wires surrounded by a polymer coating.

Explain why

• the wire is made of metal

• the metal wire is coated with a polymer.

Use information from the table in your answer.

[3]

Answer

(b)

Aluminium is a metal.

Aluminium is extracted from an ore called bauxite.

Electrolysis is used to extract the aluminium.

Use the reactivity series to explain why aluminium cannot be extracted from bauxite by heating the bauxite with carbon.

$Question 23, shown as an image$

[1]

Answer

(c)

Drinks cans are often made from aluminium.

4.0 kg of bauxite makes 1.0 kg of aluminium.

285 000 kJ of energy is needed to make 1.0 kg of aluminium from bauxite.

Aluminium can be recycled.

4.0 kg of recycled aluminium makes 3.8 kg of aluminium.

14 250 kJ of energy is needed to produce 1.0 kg of aluminium from recycled aluminium.

(c)(i)

Describe how aluminium is recycled.

[2]

Answer

(c)(ii)

Describe and explain two advantages of recycling aluminium.

Use the information in the question in your answer.

[3]

Answer

The Haber process is used to manufacture ammonia, NH₃.

Ammonia is used to make fertilisers, which farmers use on their crops.

(a)

Explain why fertilisers are so important in the agricultural production of crops.

[2]

Answer

(b)

Ammonium sulfate is a fertiliser made from ammonia and sulfuric acid.

The diagram shows the stages in the industrial production of ammonium sulfate.

Complete the diagram to show the raw materials in the production of ammonium sulfate.

Raw Materials

[2]

Answer

(c)

Ammonium nitrate, NH₄NO₃, is another fertiliser made from ammonia.

Ammonium nitrate is made by reacting ammonia with nitric acid.

$Question 24, shown as an image$

(c)(i)

Calculate the mass of ammonium nitrate that could be made from 25.5 tonnes of ammonia.

A_r: H = 1.0, N = 14.0, O = 16.0

Mass of ammonium nitrate =........ tonnes

[3]

Answer

(c)(ii)

A student makes some ammonium nitrate in the laboratory.

He predicts that he should make 12.5 g of ammonium nitrate.

His percentage yield is 80%.

Calculate the actual mass of ammonium nitrate that the student makes.

[2]

Answer

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OCR J248 · Paper 2

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

Question 23

Question 24