OCR GCSE Combined Science A (Gateway) Chemistry Paper 4 Foundation November 2021 question paper J250/04

The burning of fossil fuels can produce gases that cause acid rain.

Which gas causes acid rain?

A Carbon monoxide

B Nitrogen

C Oxygen

D Sulfur dioxide

The table shows information about four different elements.

Which element, A, B, C or D, is in Group 7 of the Periodic Table?

The diagram shows the main stages in a life-cycle assessment of a product.

What is the name of Stage X ?

A Disposal

B Extraction

C Packaging

D Production

The Earth’s early atmosphere contained little or no oxygen.

Which process produced the oxygen found in the Earth’s atmosphere today?

A Burning fossil fuels

B Photosynthesis by plants and algae

C Respiration by bacteria

D Volcanic activity

Which statement about the Group 0 elements is correct?

A They exist as simple molecules.

B They exist as single atoms.

C They react to form giant covalent molecules.

D They react to form ionic compounds.

Many scientists believe that increased levels of methane in the atmosphere are contributing to global warming.

What causes increased levels of methane in the atmosphere?

A Cutting down trees

B Exhaust gases from car engines

C Incomplete combustion of fossil fuels

D Waste gases from cows and landfill sites

Octane, C₈H₁₈, is a compound in petrol.

Which statement about octane is correct?

A It is a hydrocarbon with a relative molecular mass of 66.

B It is a hydrocarbon with the empirical formula C₄H₉.

C It is extracted from crude oil by filtration.

D It is in the bitumen fraction of crude oil.

Sodium reacts with water to form sodium hydroxide and hydrogen.

What is the correctly balanced symbol equation for this reaction?

A copper ore contains 66.4% copper. The ore is CuS.

What is the maximum mass of copper that can be extracted from 500 tonnes of the ore?

A 7.53 tonnes

B 66.4 tonnes

C 332 tonnes

D 33 200 tonnes

The diagram shows the percentage of greenhouse gases made from different sources.

The percentage of greenhouse gases produced from Residential is twice that produced from Agriculture.

What is the percentage of greenhouse gases produced from Residential?

A 9%

B 18%

C 27%

D 36%

In 2010, scientists discovered a new Group 7 element called tennessine. Its symbol is Ts.

The diagram shows where tennessine is placed in Group 7 of the Periodic Table.

Use your knowledge of the properties and trends of the Group 7 elements to predict the answer to the following questions.

How many outer shell electrons are there in an atom of tennessine?

1 7 17

What is the physical state of tennessine at room temperature?

gas liquid solid

This question is about the Group 1 metals.

A teacher adds a small piece of a Group 1 metal to a trough of water, as shown in Fig. 12.1

The metal burns with a lilac flame, sparks and explodes.

Which Group 1 metal did the teacher add to the water in Fig. 12.1 ?

lithium sodium potassium rubidium caesium

Sodium is a soft metal with a dull coating.

It is shiny when it is freshly cut.

After several seconds, the shiny surface goes dull.

Which gas in the air reacts with the sodium as it goes dull?

What is the name of the chemical compound made as the sodium goes dull?

How long would it take a piece of freshly cut lithium to go dull compared to sodium?

Give a reason for your answer.

Fig. 12.2 shows the trend in the density of the Group 1 metals from lithium to caesium.

Which Group 1 metal does not fit the general trend?

Give a reason for your answer using information from Fig. 12.2.

Crude oil is a mixture of different chemicals called fractions.

What is the name of the process used to separate crude oil into fractions?

Table 13.1 shows the stages in the separation of crude oil into fractions.

The stages are not in the correct order.

Write W, X, Y and Z in the boxes to show the correct order of the stages.

Table 13.2 shows information about the different gases in the LPG (liquefied petroleum gas) fraction separated from crude oil.

Write the name of the homologous series of the gases in the LPG fraction.

Use the data in Table 13.2 to estimate the boiling point of butane.

The equation shows the reaction for methane burning in a limited amount of oxygen.

Write down the name of the hazardous gas formed in this reaction.

State why the gas identified in (d)(i) is hazardous to humans.

A student investigates heating hydrated copper(II) sulfate, CuSO₄.5H₂O.

The diagram shows the experiment they do.

The student:

• Measures the mass of a boiling tube.

• Puts about 5 g of hydrated copper(II) sulfate in the boiling tube and measures the mass.

• Gently heats the boiling tube for one minute.

• Lets the boiling tube cool down and measures the mass.

During the experiment the hydrated copper(II) sulfate turns from blue to white and water vapour is produced.

Look at the student’s results.

Calculate the mass of water produced in the experiment.

The student expected a greater mass of water to be produced.

How could they improve the experiment so a greater mass of water vapour is produced?

Complete and balance the symbol equation.

The student adds a few drops of water to a boiling tube containing some of the white solid.

Describe what the student observes happening to the white solid.

Give a reason for your answer.

Observation........

Reason........

As water reacts with the white solid, the temperature of the boiling tube increases.

What name is given to this type of reaction where heat is transferred to the surroundings?

Aluminium is produced from aluminium oxide by electrolysis.

The diagram shows the industrial electrolysis of aluminium oxide.

Look at the equation for the electrolysis of aluminium oxide.

Complete the balanced symbol equation for the reaction.

Molten aluminium oxide contains Al³⁺ and O²⁻ ions. (b)

Explain why the aluminium oxide must be molten during electrolysis.

Explain why aluminium is produced at the cathode.

Aluminium melts at 650 °C.

Describe two reasons why it is cheaper to recycle aluminium than to produce it from electrolysis.

The gradient of the tangent gives the rate of reaction. Use the tangent to calculate the rate of reaction at the start of the reaction.

Give your answer to 1 decimal place.

Rate of reaction =........ cm³ / minute

What happens to the rate of reaction as the reaction progresses?

Explain your answer using ideas about particles and collisions.

Another student repeats the experiment.

They increase the concentration of the dilute hydrochloric acid. They keep everything else in the experiment the same.

Does the gradient of the graph at the start of this student’s reaction decrease, increase or stay the same compared to the first student’s experiment?

Tick (✓) one box.

Give a reason for your answer.

Write down the volume of hydrogen gas that is produced at the end of this reaction.

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

The student observes that bubbles are produced slowly during the reaction.

They want to find a catalyst for the reaction. They repeat the experiment, but each time they add a small piece of a different metal, R, S and T.

Look at the student’s results.

State if the metals, R, S and T are catalysts or not.

Explain your answers using the information in the table and your knowledge of catalysts.