OCR GCSE Combined Science A (Gateway) Chemistry Paper 9 Higher June 2023 question paper J250/09

Which substance is described as pure by a scientist?

A A solution of sodium chloride

B An alloy

C Dilute sulfuric acid

D Distilled water

A metal oxide has the formula X₂O, where X is a Group 1 metal.

The relative formula mass of the metal oxide is 94.2.

Relative atomic mass (A_r): O = 16.0

What is the name of X ?

A Lithium

B Potassium

C Rubidium

D Sodium

Which gas bleaches damp litmus paper?

A Carbon dioxide

B Chlorine

C Hydrogen

D Oxygen

Copper carbonate reacts with dilute hydrochloric acid to form copper chloride, water and a gas.

What is the formula of the gas?

A C

B CO

C CO₂

D CO₃

Which row lists the material that has the weakest intermolecular forces?

Which diagram shows the correct equipment diagram for simple distillation?

Which scientist developed this model of the atom?

C Rutherford

D Thomson

Lead, Pb, and dilute nitric acid, HNO₃ react.

Which row correctly balances the equation?

This is the symbol for helium.

What is the mass of one atom of helium?

The Avogadro constant = 6.02 × 10²³

A 3.32 × 10^–24 g

B 6.64 × 10^–24 g

C 1.51 × 10²³ g

D 3.01 × 10²³ g

The diagram shows the particle model for the condensation of a gas into a liquid.

Which is a limitation of the particle model?

A It does not show the arrangement of the particles.

B It does not show the movement of the particles.

C It does not take account of the energy of the particles.

D It does not take account of the forces between particles.

Atoms of the same element can have different structures.

Fig. 11.1 shows the structure of two different atoms, Y and Z, of the same element.

Fig. 11.1

What name is given to different atoms of the same element such as Y and Z ?

Write the number of protons, neutrons and electrons in an atom of Z.

Write the mass number of an atom of Z.

Write the name of the element that contains atoms of Y and Z.

Use the Periodic Table.

Complete Fig. 11.2 to show the arrangement of electrons in the ions.

What is the formula of the ionic compound formed when atoms of sodium react with atoms of Y ?

Tick (✓) one box.

Why does sodium react with Y and Z in a similar way?

Tick (✓) one box.

The ionic compound formed in Fig. 11.2 has a high melting point.

Explain why. Use ideas about structure and bonding.

Thin layer chromatography (TLC) is used to analyse and identify unknown samples.

Fig. 12.1 shows the apparatus used for thin layer chromatography.

Fig. 12.1

Identify the stationary phase and mobile phase shown in Fig. 12.1.

What determines how far the sample travels up the TLC plate?

Tick (✓) one box.

Fig. 12.2 shows the final TLC plate for a sample.

Fig. 12.2

Calculate the R_f value for the sample.

Give your answer to 2 decimal places.

Diamond and graphite are different forms of the same element.

The diagrams show the structures of diamond and graphite.

Describe and explain one property of graphite that is different from diamond.

Describe and explain one property that is similar for both diamond and graphite.

A student thinks that the models used to represent diamond and graphite have limitations.

Give one reason why they are correct.

Describe the difference between a strong acid and a weak acid.

Hydrochloric acid, HC l (aq), is an example of a strong acid.

The graph shows the pH of a dilute hydrochloric acid solution at different concentrations.

Concentration of dilute hydrochloric acid solution (mol/dm³)

Write the formula of the ion that gives the dilute hydrochloric acid solution the pH shown on the graph.

The pH of the dilute hydrochloric acid solution can be measured using either universal indicator or a pH meter.

Explain which method would be better to use for measuring the pH shown on the graph.

Describe how the pH changes with the concentration of dilute hydrochloric acid solution on the graph.

As the concentration of the dilute hydrochloric acid solution increases by a factor of ten, the pH of the solution decreases by one.

Use data from the graph to show that this statement is true.

Calculate the mass of hydrochloric acid, HCl, in 100 cm³ of solution that gives a pH 1.5. (e)

Use data from the graph.

Give your answer to 2 significant figures.

Relative molecular mass (M_r): HCl = 36.5

Calculate the total energy transferred to break all the bonds in the reactants.

Energy transferred to break all the bonds =........ kJ / mol

Calculate the total energy transferred when all the bonds in the products are made.

Energy transferred when all the bonds are made =........ kJ / mol

Use your answers to parts (i) and (ii) to calculate the energy change for the reaction.

Energy change =........ kJ / mol