OCR GCSE Chemistry B (21st Century) Paper 2 November 2021 question paper

The exhaust gases from diesel car engines contain nitrogen oxides.

Complete the sentences about nitrogen oxides.

Nitrogen oxides form in the engine when nitrogen from the air / fuel reacts with oxygen.

This happens because in car engines the gases are very concentrated / hot

Nitrogen oxides are harmful because they cause acid rain / particulates.

Amir says that nitrogen oxides are reduced during the reaction.

Give one reason why Amir is correct.

Jamal says that the reaction also involves oxidation.

Give one reason why Jamal is right.

Complete the table by giving the name of each new gas formed in the reaction.

Amir says that the three new gases formed are not harmful to health or to the environment.

Do you agree with Amir? Explain your answer.

Layla heats a small piece of sodium. She then puts it in a jar of chlorine gas, as shown in Fig. 2.1

Layla observes that the sodium burns quickly with a bright flame and forms a white solid. The white solid is sodium chloride.

Layla repeats the experiment. This time she uses lithium.

What is the name of the salt that forms when lithium reacts with chlorine?

How would Layla's observations be different when she uses lithium?

Reaction is slower Reaction is faster Reaction takes same amount of time

Give one reason for your answer to (a)(ii).

Layla does experiments with other Group 1 and Group 7 elements.

Complete the table of information about each element.

Fig. 2.2 shows the arrangement of electrons in a chlorine atom.

Chlorine (atomic number 17)

Fig. 2.2

Complete Fig. 2.3 to show the arrangement of electrons in a sodium atom.

Sodium (atomic number 11)

Fig. 2.3

Chlorine forms chloride ions, C l –.

Complete the sentence to explain why chloride ions have a charge of –1.

Use the words.

You can use each word once, more than once, or not at all.

eight gain lose seven two

Chlorine has........ electrons in the outer shell, so it needs to

........ one electron to give a full outer shell.

Aluminium is extracted from molten aluminium oxide by electrolysis.

Explain why molten aluminium oxide conducts electricity but solid aluminium oxide does not.

Fig. 3.1 shows the tank used to electrolyse aluminium oxide.

Give the name of the product formed at each electrode in Fig. 3.1.

Product at positive electrode........

Product at negative electrode........

The temperature inside the tank is 900 C. The aluminium metal leaves the tank as a liquid.

What does this tell you about aluminium metal?

Tick (✓) one box.

What does + in Fig. 3.2 represent?

Tick (✓) one box.

Describe what happens when a metal conducts electricity.

Give two reasons why copper is a better choice than silver or aluminium for most electrical wiring.

Use the table to help.

Aluminium is used to make overhead power cables.

Give one advantage and one disadvantage of using aluminium rather than copper for overhead power cables.

Advantage

Disadvantage

Many shops sell boxes of tablets to treat stomach upsets. Some of these tablets contain calcium carbonate, CaCO₃.

Jane does experiments to measure the mass of calcium carbonate in three different brands of tablets.

Jane wants to make sure that the tablets she tests are representative of all the tablets in each brand.

What should Jane do to make sure her choice of tablets is representative ?

Tick (✓) two boxes.

Jane reacts dilute hydrochloric acid with each tablet. The equation shows the reaction that happens:

Which two statements explain why this reaction is a neutralisation reaction?

Tick (✓) two boxes.

What else does Jane need to add to the flask before she starts her titration?

Give one reason for your answer to (c)(i).

Which brand of tablet contains the most calcium carbonate?

EasyCalm FeelRight RumbleTum

Calculate the relative formula mass of calcium carbonate, CaCO₃.

Use the Data Sheet.

The label shows all of the ingredients in FeelRight tablets.

How will magnesium hydroxide affect the volume of acid needed to neutralise each tablet of FeelRight?

Give one reason for your answer to (d)(i).

Table 5.1 and Table 5.2 show information about the structure, properties, and uses of graphite and graphene.

* Explain the similarities and differences between graphite and graphene.

Use ideas about structure in your answer.

Use information from Table 5.1 and Table 5.2 in your answer.

Which two materials also contain only carbon atoms?

Crude oil Diamond Fullerenes Methane Polymers

New types of batteries that contain nanoparticles of graphene have been available for less than 10 years. New products need to have a life cycle assessment.

Suggest two factors that need to be considered in a life cycle assessment for a new graphene battery.

Table 6.1 shows the concentration and the pH of some dilute acids.

All of the acids in the table react with magnesium metal.

Which acid gives the fastest reaction?

Tick (✓) one box.

Alex has an idea about pH.

Does the data in Table 6.1 agree with Alex’s idea?

Use data from Table 6.1 to explain your answer.

Alex tests the pH of some samples of dilute nitric acid. He uses Universal Indicator and a pH meter.

Table 6.2 shows his results.

Describe how Alex uses Universal Indicator to measure the pH of the acids.

Alex says that the results in Table 6.2 contain an outlier.

Explain your answer to (c)(ii).

Alex says that using a pH meter rather than Universal Indicator to measure pH improves the quality of the data.

Suggest one reason why this is true.

7* Kareem finds this table of information about the reactivity of some metals with dilute acids.

He does some experiments to show that the reactivity of these metals is correct.

He uses the apparatus shown in the diagram.

Kareem finds that it takes 45 seconds for magnesium to make 10 cm³ gas.

Describe how Kareem should use the same apparatus to do experiments to show that the reactivity of the metals shown in the table is correct.

Include in your answer what he should control and what results he should expect.

Lithium (Li), sodium (Na) and potassium (K) are in Group 1 of the Periodic Table.

How does the atomic radius change down Group 1? Use the graph.

Give the symbols of the two elements which have the smallest atoms. Use the graph.

Which group of the Periodic Table do the elements in (b)(i) belong to? Use the Data Sheet.

Which statements in the table are true and which are false ?

Tick one box (✓) in each row.

Kai makes a scale model of a lithium (Li) atom.

The diagram shows the radius of his model of a lithium atom.

Model of a lithium (Li) atom

Kai makes a model of a sodium (Na) atom to the same scale.

Calculate the radius of the sodium atom model, in cm.

Use the graph.

Kai makes his lithium model red to match the flame test colour of lithium.

What colour should he make his sodium model?

Kai designs a sign to tell people about the particles inside a sodium atom.

Complete the missing information on the sign.

More information about the particles

Hydrogen peroxide is a waste product produced by cells in our bodies. Hydrogen peroxide is broken down by an enzyme to form water and oxygen.

Beth adds a small amount of an enzyme to some hydrogen peroxide. She collects the oxygen given off in a gas syringe. She records the total volume of oxygen every minute.

The graph shows her results.

Use the graph to help you answer (a).

How long does it take for the reaction to finish?

How much oxygen is given off by the end of the reaction?

Calculate the average volume of oxygen given off per second.

........ cm³ / s

The reaction that breaks down hydrogen peroxide does not start until the enzyme is added. When the enzyme is added, oxygen is given off quickly.

Explain this statement.

Use ideas about rates of reaction in your answer.