OCR GCSE Chemistry B (21st Century) Paper 2 June 2018 question paper

Table 1.1 shows some information about diamond, graphite and carbon dioxide.

Complete Table 1.1 by filling in the state for graphite and carbon dioxide.

Explain why diamond and graphite are elements, but carbon dioxide is a compound.

Diamond and graphite have giant covalent structures. Carbon dioxide has a simple covalent structure.

Explain how the diagrams of their structures show that these statements are true.

Nitrogen oxides are pollutant gases that are produced when coal burns in a power station.

Nitrogen monoxide is one type of nitrogen oxide that is formed in a power station.

The reaction that forms nitrogen oxide can be shown in an equation.

Complete the word and balanced symbol equation by filling in the boxes.

Which statements about nitrogen oxides are true and which are false ?

Put a tick (✓) in one box in each row.

The graph shows information about the concentration in parts per billion (ppb) of nitrogen oxides in the air between 1980 and 2012.

Describe how the highest daily concentration of nitrogen oxides changed between 1980 and 2012.

The World Health Organisation recommends a safe limit for people to be exposed to nitrogen oxides. They recommend that this limit is 100 ppb.

Why is it necessary to set a safe limit for exposure to nitrogen oxides?

Layla and Mia talk about the graph. Layla says that the nitrogen oxides have been below the safe limit since 1990. Mia says that nitrogen oxides have only been below the safe limit since 2004.

Explain how the graph could be used to support both of these ideas.

Layla’s idea........

Mia’s idea........

Mauritius is a country of small islands surrounded by sea. There is almost no fresh water in Mauritius.

A distillation process is used to produce fresh water.

Statements A–G describe some correct and some incorrect stages in the distillation process.

Put the correct statements in the correct order.

The first and last have been done for you.

Chlorine is used to treat drinking water before it is sent to homes. The waste water from homes is treated with oxygen.

The table shows some information about oxygen and chlorine.

Complete Table 3.1 by filling in the missing information.

Complete Table 3.2 below to show the tests and results used to identify oxygen and chlorine gas.

The alkanes and the alkenes are both examples of homologous series.

Table 4.1 shows the names and chemical formulae of some alkanes.

Table 4.1

Down the series, the number of carbon atoms and hydrogen atoms increases by the same amount each time.

Use examples from Table 4.1 to show that this statement is true.

Pentane is an alkane with five carbon atoms.

Predict the formula of pentane.

Table 4.2 shows the names and formulae of some alkenes.

Complete Table 4.2 by drawing the displayed formula for propene.

There is no alkene called ‘methene’.

Which statement explains why ‘methene’ cannot exist?

Tick (✓) one box.

The general formula for all of the alkenes is C_nH_2n. The empirical formula for all of the alkenes is CH₂.

Use examples from Table 4.2 to explain why all of the alkenes have the same general formula, C_nH_2n.

Explain why the empirical formula of all of the alkenes is CH₂.

The diagram shows the arrangement of electrons in an atom of fluorine.

Use the diagram and the Periodic Table provided to complete the missing information in the

This diagram shows the arrangement of electrons in a fluoride ion.

Describe one way that an atom of fluorine and a fluoride ion are the same and one way that they are different.

Same........

Different........

What is the formula of a fluoride ion?

Amir makes some copper chloride. He reacts copper oxide with dilute hydrochloric acid.

This is an equation for the reaction.

Amir does a calculation to work out how much copper chloride he can make from some copper oxide (the theoretical yield).

He starts by working out the relative formula masses of the compounds in the equation.

Complete Table 6.1 by working out the missing relative formula masses.

Use the Periodic Table to help you.

Amir uses 8 g of copper oxide in his experiment.

What is the theoretical yield of copper chloride from 7.95 g of copper oxide? Use Table 6.1 and the equation to help you.

0.1345 g 1.345 g 13.45 g 134.5 g

Amir adds 8 g of solid copper oxide to a small amount of dilute hydrochloric acid in a beaker. Some of the copper oxide does not react.

He now has a mixture which contains a solution of copper chloride and some solid copper

Amir uses different techniques to separate solid copper oxide and to obtain crystals of copper chloride from the mixture.

Draw lines from each substance to the correct technique.

Amir’s percentage yield for this experiment is very low.

Suggest a reason why.

Eve measures the volume of gas given off when solid calcium carbonate reacts with a dilute acid.

Fig. 7.1 shows a graph of her results.

What volume of gas is given off during the first minute of the reaction?

What volume of gas is given off during the second minute of the reaction?

Look at the graph in Fig. 7.1.

Describe what happens to the rate of the reaction during the experiment.

Eve does some more experiments.

She measures the rate of reaction when she uses different concentrations of acid.

Table 7.1 shows her results.

Table 7.1

Predict the rate of reaction when acid of concentration 0.5 mol / dm³ is used. (i)

Rate of reaction =........ cm³ / s

Eve says that the data shows that rate of reaction is proportional to the concentration.

How does the data show that Eve is right?

Eve writes an expression to show that rate of reaction is proportional to concentration.

Which expression shows that rate of reaction is proportional to concentration?

Tick (✓) one box.

Salt that is used for food contains compounds of Group 1 elements. One type of food salt is called ‘Healthy salt’.

Ben wants to find out what the difference is between table salt and ‘Healthy salt’.

He does some experiments to find the emission spectra of some Group 1 elements. He also does experiments to find the emission spectra of table salt and ‘Healthy salt’.

He puts small samples of each element and salt in a spectroscopy machine and looks at the print-out of results.

Here are Ben’s results.

Element
Emission spectrum

Food salt
Emission spectrum

* What conclusions can you make about the elements that table salt and ‘Healthy salt’ do and do not contain? Explain how the lines in both emission spectra support your conclusions.

Elements in salts can also be identified using chemical tests.

Each test involves adding chemicals to the salts and looking for colour changes or reactions.

Ben thinks that spectroscopy is a better method to use to identify the elements.

What are the advantages and disadvantages of using spectroscopy rather than chemical tests to identify elements?

Ben says that spectroscopy is a qualitative technique. He says that he wants to try a quantitative technique to find out more about the salts.

Draw lines to connect each technique with its use.

Soft drinks are sold in containers made from PET (a polymer), aluminium and glass.

PET bottle
Aluminium can
Glass bottle

All three containers are non-biodegradable.

Many people want to choose containers that cause less harm to the environment.

Table 9.1 shows some information about the life cycle of the containers.

* Use the data from Table 9.1 to explain why all of the containers cause some harm to the environment and decide which container causes the least harm.

Table 9.1 does not include all of the factors needed to do a full life cycle assessment for the drinks containers.

Which two factors will have the biggest effect on the life cycle assessment of the drinks containers?

Tick (✓) two boxes.

Kai works in a research laboratory for a company that produces organic carbon compounds.

Kai has three unlabelled samples of different compounds. All are colourless liquids.

Kai thinks that one of the compounds might be an alkene. He thinks that another of the compounds might be a carboxylic acid. He thinks the third compound is neither an alkene nor a carboxylic acid.

Describe some simple experiments that Kai could use to find out which compound is which.

Include two tests and the expected results in your answer.

At what concentrations is ethanoic acid harmful, but not corrosive?

Suggest a concentration at which ethanoic acid is flammable.

Kai adds very concentrated ethanoic acid to ethanol and heats the mixture.

Suggest some safety procedures for Kai to use to make sure that he is safe during this experiment.

Some of Mendeleev’s groups contain similar elements to groups in the modern Periodic Table.

Which group in Mendeleev’s table contains the elements now found in Group 14 of the modern Periodic Table?

None of the elements from Group 18 of the modern Periodic Table are shown on Mendeleev’s table.

Suggest a reason why.

Mendeleev put some of the transition metals into his Group 8.

He put some other transition metals into the other groups.

Give the symbols for three transition metals in Mendeleev’s table that he did not put in Group 8.

The transition metals are in the same block of the modern Periodic Table because their properties are similar to each other.

Which property do all the transition metals have?

Tick (✓) one box.

Transition metal salts are acidic.

Sundip does an experiment to test the acidity of some solutions of transition metal salts. She uses Universal Indicator and a colour chart to find the pH of each salt.

These are Sundip’s results.

Describe how Sundip uses Universal Indicator to test the pH of the solutions of the salts.

Sundip thinks her results do not show the difference in pH between the salts. She thinks she needs to improve the precision of her pH results.

Explain why she needs to improve her precision and suggest how she can change her experiment to do this.