OCR GCSE Combined Science A (Gateway) Chemistry Paper 3 Foundation June 2022 question paper J250/03

A black ink is a mixture of different colours.

The diagram shows how the colours in the black ink can be separated.

What is the name of this method of separation?

A Chromatography

B Crystallisation

C Distillation

D Filtration

What is the test for oxygen gas?

A It goes ‘pop’ when lit.

B It relights a glowing splint.

C It turns damp red litmus paper blue.

D It turns limewater cloudy.

The table shows the start and end temperatures of four different reactions.

Which reaction is endothermic?

The table shows the colours of universal indicator in solutions of different pH.

A sample of water has a pH of 7. A small amount of dilute hydrochloric acid is added to the water.

Which colour does universal indicator turn in this solution?

A Blue

B Green

C Orange

D Purple

The diagram shows the electrolysis of molten copper chloride, CuCl₂.

Chlorine is formed at electrode X and copper is formed at electrode Y.

Which row in the table describes electrodes X and Y ?

The diagram shows the reaction profile for a reaction.

Which row represents the activation energy and the energy change for the reaction?

Which particles in a metal allow it to conduct electricity ?

A Atoms

B Electrons

C Ions

D Protons

A molecule of glucose has the molecular formula C₆H₁₂O₆.

What is the empirical formula of glucose?

A CHO

B CH₂O

C C₆H₁₂O₆

D (CO₆)H₁₂

The equation shows the reaction between carbon dioxide, CO₂, and hydrogen, H₂.

What is the oxidising agent in the reaction?

A CO

B CO₂

C H₂

D H₂O

Complete each sentence to describe the formation of nitrogen dioxide.

Use the words or phrases in the list.

The molecules of nitrogen and oxygen........

The atoms then........ to form nitrogen dioxide.

This is called a........

The equation shows the formation of nitrogen dioxide.

Complete the balanced symbol equation for the reaction.

Use Fig. 11.1.

The table shows the melting point and boiling point of pure nitrogen dioxide.

Which state symbol shows the physical state of nitrogen dioxide at –2 °C?

Tick (✓) one box.

A scientist measures the melting point of a sample of nitrogen dioxide.

The result shows that the sample of nitrogen dioxide is impure.

Which temperature could be the melting point of the impure nitrogen dioxide?

Tick (✓) one box.

A molecule of nitrogen dioxide has the formula NO₂.

Calculate the relative formula mass for nitrogen dioxide.

Relative atomic mass (A_r): N = 14.0 O = 16.0

Nitrogen dioxide is made from the reaction of nitrogen with oxygen.

Fig. 11.2 shows the bonding in a molecule of oxygen, O₂.

Fig. 11.2

Fig. 11.3 shows an incomplete dot and cross diagram for oxygen.

Fig. 11.3

Complete Fig. 11.3 to show the arrangement of the electrons in a molecule of oxygen.

Atoms are made from protons, neutrons and electrons.

The table shows the relative mass and relative charge of a proton, neutron and electron.

Complete the table.

Write your answers in the three boxes in the table.

An atom of helium contains:

• 2 protons

• 2 neutrons

• 2 electrons.

Draw a labelled diagram to show the arrangement of protons, neutrons and electrons in an atom of helium.

Which two elements are in Group 1 of the Periodic Table?

Which element is in Period 4 of the Periodic Table?

Which element has a mass number of 12?

Which two elements are isotopes?

Which element forms an ion with a 2+ charge?

Aluminium forms an Al³⁺ ion and chlorine forms a Cl^– ion. (e)

Three students write down the formula of aluminium chloride.

Student A: A l C l

Student B: Al Cl₃

Student C: Al₃Cl

Which student is correct?

Explain your answer.

A student investigates how the mass changes as magnesium reacts with excess dilute sulfuric acid.

The diagram shows the apparatus they use.

The student measures the mass every minute for 8 minutes.

Table 13.1 shows their results.

Table 13.1

Complete the table with an estimate of the missing mass at 3 minutes.

Write your answer in the box in Table 13.1.

The student thinks that the results show that all the magnesium had reacted.

Explain why the student is correct. Use data from Table 13.1.

The student repeats the experiment three times.

Table 13.2 shows the results of the three experiments at 1 minute.

Table 13.2

Calculate the mean mass in the three experiments.

Give your answer to 1 decimal place.

Fullerenes are allotropes of carbon that have many uses.

Fig. 15.1 shows a molecule of a fullerene.

Fig. 15.1

Which group of allotropes contain this fullerene?

Tick one (✓) box.

The carbon atoms in fullerenes are joined by covalent bonds.

Explain how two atoms of carbon form a covalent bond.

How many covalent bonds does one atom of carbon form in a molecule of fullerene, as shown in Fig. 15.1 ?

The model used to show the molecule of fullerene in Fig. 15.1 has limitations.

The table shows some statements about the model.

Which statements about this model are true, and which are false ?

Tick (✓) one box in each row.

Fullerenes can be used as lubricants. Lubricants reduce the friction between moving parts.

Fig. 15.2 shows a lubricant being sprayed onto the chain of a motorbike.

Fig. 15.2

Explain why fullerenes can be used as lubricants.

Use ideas about the structure and bonding of the fullerene shown in Fig. 15.1 in your answer.

A lubricant may need to be used at high temperatures.

Explain why fullerenes can be used at high temperatures.

Use ideas about the structure and bonding of the fullerene shown in Fig. 15.1 in your answer.