OCR GCSE Combined Science B (21st Century) Paper 6 June 2022 question paper

The table gives information about some of the compounds present in crude oil.

Complete the table to show the missing molecular formula and empirical formula.

Predict the boiling point for the compound with 7 carbon atoms.

Predict the state of the 5 carbon compound at room temperature (20 °C).

Explain your answer.

All the compounds in the table are in the same homologous series.

All members of a homologous series have the same general formula.

Give two other characteristics of a homologous series that are shown in the table.

Solid calcium carbonate reacts with dilute hydrochloric acid to form calcium chloride, carbon dioxide and water.

Jane investigates the rate of this reaction. She measures the change in mass during the reaction over five minutes.

She uses 10 g of calcium carbonate lumps and 50 cm³ of dilute hydrochloric acid.

The graph shows Jane’s results.

What was the time taken for the reaction to finish?

What was the total mass lost during the reaction?

Calculate the average rate of the reaction.

Rate of reaction =........ g / s

Jane repeats the experiment with 10 g of calcium carbonate powder instead of 10 g of lumps. She keeps everything else the same.

Sketch a line on the graph to show the results she should expect.

Complete the sentences to explain why the rate of reaction changes when powdered calcium carbonate is used instead of lumps.

The surface area of 10 g of powdered calcium carbonate is larger than / smaller than / the same as 10 g of lumps.

The total volume of 10 g of powdered calcium carbonate is larger than / smaller than / the same as 10 g of lumps.

Calcium is a metal in Group 2 of the Periodic Table. Chlorine is a non-metal in Group 17(7) of the Periodic Table.

Table 3.1 shows some properties of calcium and chlorine.

Describe one other property, not shown in Table 3.1, which is different for metals and non-metals.

The difference in properties of metals and non-metals is caused by their electronic structures.

Give the electronic structures of calcium and chlorine.

Calcium........

Chlorine........

Explain why calcium and chlorine form different types of ions.

The boiling points of calcium and chlorine are different because of the forces of attraction between particles.

Draw lines to connect each element to the forces of attraction between its particles.

Explain why the boiling points of calcium and chlorine are different.

Use your answer to (i) to support your answer.

Metals and non-metals react together to form ionic compounds.

Table 3.2 shows some information about three ionic compounds.

Complete the table to show the ions in potassium oxide and the formula of aluminium oxide.

Metals and ionic compounds can form lattices.

The diagram shows four different lattice structures.

Which two structures are the lattice of a metal?

Which structure is the lattice of potassium oxide (K₂O)?

Explain your answer.

Complete the balanced symbol equation for the reaction of aluminium with sodium hydroxide.

How does the equation show that contact with aluminium surfaces is a hazard?

Tests can be used to identify gases produced in a reaction.

Complete the table to show the method and the result for the tests for the three gases.

Sam does a titration to find the amount of sodium hydroxide in the oven cleaner.

This is the method:

• Measure out 3.00 g of the cleaner into a conical flask

• Add a few drops of indicator

• Add 0.25 mol / dm³ hydrochloric acid until all of the sodium hydroxide has reacted.

The equation shows the reaction of sodium hydroxide with hydrochloric acid.

Calculate the range of the mass of sodium hydroxide expected in 3 g of oven cleaner.

Use information from the label.

Mass of sodium hydroxide is from........ g to <........ g

How does Sam know when all the sodium hydroxide has reacted?

Sam wants to measure the exact volume of acid needed for all of the sodium hydroxide to react.

Describe one thing Sam should do so that the titration result is accurate.

Sam finds that 24.8 cm³ of 0.25 mol / dm³ hydrochloric acid is needed to react with the (d) sodium hydroxide in 3.00 g of oven cleaner.

Calculate the number of moles of hydrochloric acid in 24.8 cm³ of 0.25 mol / dm³. (i)

Find out how many moles of sodium hydroxide react with this amount of acid.

Calculate the mass of sodium hydroxide (NaOH) reacting with the acid.

Use the formula and the relative atomic masses given.

Relative atomic masses: Na = 23.0, O = 16.0, H = 1.0

Mass of sodium hydroxide =........ (g)

Table 5.1 shows information about some pollutants in the air over 100 days in 2020.

Calculate the orders of magnitude for the change in each pollutant in 2020.

Table 5.2 shows information about the same pollutants in the air over a 100-day period in 5 years from 2015–2019.

Sundip looks at the data in Table 5.1 and Table 5.2 and says: ‘The changes in these pollutants during 2020 are not significant. They go up and down each year.’

Explain why she is only partially correct.

Use data from Table 5.1 and Table 5.2 to support your answer.

These pollutants are all emitted from car exhausts. Particulates are tiny carbon particles and NO and NO₂ are oxides of nitrogen.

Describe how particulates and oxides of nitrogen are produced by car engines.

Oxides of nitrogen........

Carbon monoxide, carbon dioxide and sulfur dioxide are also emitted from car exhausts.

Draw lines to connect each gas with the main problem caused by increased amounts of the gas in the atmosphere.

Ammonia is manufactured from nitrogen and hydrogen. When nitrogen and hydrogen gases are mixed, they come to a dynamic equilibrium.

What is happening to the rates of the forward and reverse reactions when it is at dynamic equilibrium ?

Why is the yield of the reaction not 100%?

* The yield of ammonia is affected by changing the conditions of the reaction vessel.

Table 6.1 shows the percentage yield at different temperatures and pressures.

Chemical companies choose the most effective conditions for the manufacture of ammonia.

Table 6.2 shows the conditions chosen by one company.

Describe the effect of changing the conditions of the reaction vessel on the yield of ammonia shown in Table 6.1 and explain why the chemical company chose the conditions shown in Table 6.2.

Use ideas about yield, rate, energy use and safety in your answer.

Neutralisation is when an acid reacts with an alkali to form a salt and water. Neutralisation can also be described in terms of ions.

Complete the word and balanced symbol equations for the reaction between nitric acid and sodium hydroxide.

Identify the two ions involved in a neutralisation reaction and state where they come from.

Diamond, graphite and graphene are all allotropes of carbon.

The table shows the structure and some properties for these allotropes.

The properties of these allotropes depend on their structure.

Explain why graphite and graphene are good conductors of electricity but diamond is not.

Explain why diamond and graphene are hard but graphite is soft.

Diamond and graphene........

Graphene sheets are one atom deep.

What is the depth of a graphene sheet?

Carbon nanotubes are graphene sheets rolled into a tube.

Graphene and nanotubes are examples of nanoparticles. Nanoparticles have important uses which depend on their structure and properties.

Give one risk and one benefit of using nanoparticles to carry drugs into the body.

Risk........

Benefit........