Edexcel GCSE Chemistry Paper 1 Higher June 2023 question paper 1CH0/1H

Figure 1 shows information about two isotopes of hydrogen, A and B.

Complete the table to show the number of subatomic particles in each isotope.

Hydrogen gas and oxygen gas are used in a hydrogen–oxygen fuel cell.

Separate containers of hydrogen and oxygen are used to supply the gases.

A student tests the voltage supplied by the fuel cell every 15 minutes.

The results are shown in Figure 2.

Describe what Figure 2 shows about how the voltage of this fuel cell varies with time.

A chemical cell is made by placing two electrodes into an aqueous electrolyte.

Figure 3 shows a chemical cell.

State why sodium and sulfur electrodes are not suitable for this experiment.

sodium

sulfur

In an experiment, powdered calcium hydroxide was added to dilute hydrochloric acid and the pH was measured.

The method used was

step 1 measure 200 cm3³ dilute hydrochloric acid into a beaker

step 2 aadd 0.1 g of powdered calcium hydroxide to the beaker

step 3 find the pH of the mixture

step 4 repeat steps 2 and 3 until the pH stops changing.

State what should be done after step 2 to make sure that any reaction is complete.

Complete the word equation for the reaction.

calcium hydroxide + hydrochloric acid _........

Which row of the table shows the state symbols for powdered calcium hydroxide and dilute hydrochloric acid in the balanced chemical equation?

The results of the experiment are shown in Figure 4.

mass of calcium hydroxide added in grams

Figure 4

Using Figure 4, give the pH of the acid at the start of the experiment.

Using Figure 4, give the mass of calcium hydroxide required to make a neutral mixture.

mass of calcium hydroxide =_........

Explain why the pH starts at a low value and ends at a higher value.

Figure 5 shows part of the reactivity series of metals.

Which metal reacts when added to cold water?

A student investigates the reactivity of four different metals.

The student adds an equal‑sized piece of each metal to separate test tubes containing dilute hydrochloric acid.

The student’s observations for zinc and copper are recorded in Figure 6.

Use the information in Figure 5 and in Figure 6 to predict the observations for the reactions of magnesium and of iron with dilute hydrochloric acid.

magnesium

iron

When metals react with acids, hydrogen gas is produced.

Describe the test to show that the gas is hydrogen.

When magnesium reacts with hydrochloric acid, magnesium chloride and hydrogen are formed.

Complete the balanced equation for the reaction.

An excess of magnesium is added to some dilute hydrochloric acid of pH 2. The mass of hydrogen gas produced is measured.

The experiment is repeated with excess magnesium but with the same volume of dilute hydrochloric acid of pH 1.

State how many times greater the concentration of hydrogen ions is in the acid of pH 1 than in the acid of pH 2.

With the acid of pH 2, the mass of hydrogen gas produced when the reaction is complete is 0.005 g.

Predict the mass of hydrogen gas produced in the reaction with acid of pH 1.

There are several stages to the production of sulfuric acid in industry.

Sulfur dioxide is required for the production of sulfuric acid.

Sulfur dioxide can be obtained by heating copper sulfide, Cu₂S, in excess air.

Calculate the atom economy for the production of sulfur dioxide, SO₂, in this reaction.

(relative atomic mass: Cu = 63.5 relative formula masses: O₂ = 32.0, Cu₂S = 159.0, SO₂ = 64.0)

Give your answer to two significant figures.

atom economy =_........

In one stage vanadium oxide, V₂O₅, is used.

Based on the position of vanadium in the periodic table, which row shows the most likely melting point of vanadium and colour of vanadium oxide?

The equation shows a reaction forming sulfuric acid.

Calculate the maximum mass of sulfuric acid that could be produced from 400 tonnes of sulfur trioxide, SO₃.

(relative formula masses: SO₃ = 80, H₂SO₄ = 98)

maximum mass of sulfuric acid =_........ tonnes

Using a different amount of sulfur trioxide, it was calculated that 700 tonnes of sulfuric acid could be made.

The actual mass produced was 672 tonnes.

Calculate the percentage yield of sulfuric acid.

percentage yield =_........

State two reasons why the percentage yield is less than 100 %.

Ammonia is manufactured in the Haber process by the reversible reaction between nitrogen and hydrogen.

Write the balanced equation for the reversible reaction between nitrogen and hydrogen to make ammonia, NH₃.

Which row shows the typical conditions of temperature and pressure used in the Haber process?

In the Haber process, iron is added to the vessel where the nitrogen and hydrogen react.

State the purpose of the iron.

The reaction between nitrogen and hydrogen to make ammonia can reach dynamic equilibrium.

The reaction gives out heat.

Explain how the position of equilibrium changes if the temperature is decreased.

Compound A is a dark brown gas.

Compound B is a colourless gas.

Two molecules of A combine to form one molecule of B in a reversible reaction.

You are given

• a sealed glass tube containing an equilibrium mixture of A and B

• a beaker

• a kettle

• some ice

At room temperature, the equilibrium mixture is a pale brown colour.

Devise an experiment to show how the position of equilibrium of this reaction is affected by temperature.

The sealed tube must not be opened.

A student investigates the mass of copper produced when copper chloride solution in a beaker is electrolysed using inert electrodes.

Where is copper formed during the electrolysis?

The student investigated the change in the mass of copper formed when the current was altered.

The results are shown in Figure 7.

State and explain the trend shown in these results.

Describe how, after the power supply has been switched off, the mass of copper formed can be measured.

In another experiment, 74 mg of copper is formed.

Calculate the number of copper atoms in 74 mg of copper.

(relative atomic mass Cu = 63.5; Avogadro constant = 6.0210²³)

number of atoms =_........

Titration is used to carry out some neutralisation reactions.

Ammonium nitrate can be made by neutralisation.

State the name of the two reactants that are neutralised to make the salt ammonium nitrate.

Ammonium nitrate is a fertiliser. Another fertiliser is ammonium phosphate.

Which elements are combined in ammonium phosphate?

Titrations involve aqueous solutions and the use of burettes.

Figure 8 shows readings on part of a burette at the start and at the end of a titration.

Calculate the volume of solution added from this burette.

Give your answer to a suitable number of decimal places.

A student carries out a titration four times.

The volumes from the student’s results table are shown in Figure 9.

Tick the volumes that should be used to calculate the mean volume.

Figure 10 shows the burette and flask prepared for use by the student. The burette is supported vertically by a clamp that is not shown in the diagram.

The student wrote a description of how they used the burette.

Give three improvements to the way that the student used the burette.

In a titration a student placed alkali in the flask.

By mistake a few drops of litmus and a few drops of phenolphthalein were added to the flask.

The student added acid to the flask until the mixture was acidic.

Predict the colour change that would be seen.

In a titration a student rinsed out the flask with distilled water and did not dry it.

They used the flask for titration, adding the solution from the burette until the indicator changed colour.

State the effect, if any, on the titre volume of using the wet flask rather than a dry flask.

Crystals of copper sulfate are prepared by reacting copper oxide, a base, with dilute sulfuric acid.

Name the other product of this reaction.

During the experiment, a spatula measure of copper oxide, a black powder, is added to warm, dilute sulfuric acid in a beaker.

When the mixture is stirred, the black powder disappears and the mixture turns pale blue.

The student then adds more copper oxide until the maximum amount of copper sulfate is formed without wasting copper oxide.

Explain how the student knows when to stop adding copper oxide.

The reaction produces an aqueous solution of copper sulfate.

What is the best way to obtain crystals of copper sulfate from an aqueous solution?

When some water is removed from the aqueous solution of copper sulfate, crystals of copper sulfate are made.

Describe how the arrangement and movement of the particles change as crystals are formed from a solution.

In this reaction, copper oxide, CuO, forms copper sulfate, CuSO₄.

Explain, in terms of electrons, whether the copper in copper oxide has been oxidised, has been reduced, or has not been oxidised or reduced.

In another experiment, a copper sulfate solution with a concentration of 39.875 g dm^–3 is used.

Calculate the mass of copper sulfate dissolved in 0.300 dm³ of this solution.

Figure 11 shows the structure of a molecule of compound S.

Use Figure 11 to deduce the empirical formula of compound S.

The melting points of three samples of S are shown in Figure 12.

State whether each of these samples, A, B and C, is pure or impure and justify your answers using the information in Figure 12.

A scientist uses chromatography in an investigation of compound S.

In the conditions used, compound S has an R_f value of 0.22.

Calculate the distance the spot of compound S moves if the solvent front has moved by 2.4 cm.

*(c) A solution of sodium chloride in water needs to be separated to obtain a sample of pure, dry sodium chloride and a sample of pure water.

Figure 13 shows the boiling points of sodium chloride and water.

Explain this difference in boiling points in terms of the structure and bonding of sodium chloride and water and how this difference is used to choose a method to separate sodium chloride solution into pure, dry sodium chloride and pure water.

Buildings sometimes have water sprinklers to put out fires.

The pipes in some water sprinklers are filled with nitrogen gas to prevent corrosion when the system is not in use.

State what is meant by the term corrosion.

Nitrogen can be made from sodium azide, NaN₃.

Calculate the maximum volume, in cm³, of nitrogen produced from 110 g of sodium azide.

(relative formula mass: NaN₃ = 65;

1 mol of gas occupies 24 dm³ in the conditions used)

*(b) Compare and contrast the properties and uses of pure aluminium and pure copper with the alloys of aluminium and the alloys of copper.

Include in your answer an explanation of the similarities and the differences in the properties and the uses of a pure metal and its alloy.