OCR GCSE Combined Science B (21st Century) Paper 4 June 2018 question paper

Eve is making sodium chloride in the school laboratory.

Eve makes the sodium chloride by reacting hydrochloric acid with sodium carbonate solution.

Complete the risk assessment in Table 1.1 for the hydrochloric acid.

Eve uses a titration to react the hydrochloric acid and sodium carbonate solution in the correct quantities.

Which piece of apparatus, A, B, C or D, should she use to add the hydrochloric acid?

Eve adds a few drops of a chemical to a conical flask containing the sodium carbonate solution. The chemical added changes colour.

What is the name of this type of chemical?

Complete and balance the chemical equation for the reaction between sodium carbonate solution and hydrochloric acid.

sodium carbonate + hydrochloric acid → sodium chloride + carbon dioxide + water

Na₂CO₃ (aq) + 2 HCl (aq) → 2........ (aq) +........ (g) + H₂O (l)

Which statement about the reaction between sodium carbonate solution and hydrochloric acid is correct?

Tick (✓) one box.

Which process is used to produce solid sodium chloride from sodium chloride solution?

Tick (✓) one box.

Sodium chloride is more commonly known as salt.

In some countries, water contains high levels of salt. The salt has to be removed from the water so people are able to drink it.

Which process would separate pure water from the salt water?

Tick (✓) one box.

Describe the relationship between average sodium intake and deaths from stomach cancer.

Which statement about the graph in Fig. 1.1 is correct?

Tick (✓) one box.

Some studies have suggested that a bacterium called Helicobacter is linked with stomach cancer.

One idea is that salt affects the growth of Helicobacter.

Suggest an experiment to test this idea.

Amir is investigating electric circuits and magnetism.

Amir sets up a solenoid.

Describe how a solenoid can be made.

Amir connects the solenoid in a circuit. The circuit is shown in Fig. 2.1.

Amir closes the switch.

On the diagram in Fig. 2.1, draw:

• the direction of current flow through the solenoid

• the magnetic field lines and their direction

• the poles of the magnetic field produced.

Fig. 2.1

Amir places an iron core in the solenoid. The iron core becomes magnetised.

Amir uses the magnetised iron core to pick up paper clips. He counts the number of paper clips picked up.

He then repeats the experiment several times, each time changing the number of turns in the solenoid.

Amir’s results are shown in Table 2.1.

Complete the graph in Fig. 2.2 by plotting the results from Table 2.1 and draw a line of best fit. Some have been plotted for you.

Describe the trend shown in the graph in Fig. 2.2.

State one other way to increase the strength of the magnetic field around the solenoid.

Electromagnets are often used in scrapyards.

Which statement about electromagnets is correct?

Tick (✓) one box.

Nina is investigating alcohol (ethanol) production as a sample of beer is brewed.

Ethanol is produced by a chemical process called fermentation.

Fermentation can be represented by the following equation.

glucose → ethanol + carbon dioxide

Nina measures the rate of the reaction by recording the volume of ethanol produced by 1 dm³ (a) of beer over a period of time.

Suggest one other method for recording the rate of this reaction.

What volume of ethanol has been produced after 120 hours in Fig. 3.1 ?

Calculate the rate of ethanol produced over the first 120 hours in Fig. 3.1.

Rate =........ cm³ / h

Some other students carry out investigations to determine the rate of this reaction at different temperatures.

The graph in Fig. 3.2 shows how the rate of reaction changes over a range of temperatures.

What was the temperature range of the investigation?

Temperature range =........ °C to........ °C

Using information from Fig. 3.2, estimate the optimum temperature for fermentation.

The students want to find a more accurate estimate of the optimum temperature for fermentation.

How could they do this?

Tick (✓) two boxes.

The ethanol concentration of beer can be found by measuring its density.

Describe how to measure the density of a liquid.

Alex and Beth are investigating reaction time.

Alex drops a 30 cm ruler. Beth catches the ruler between her thumb and fingers, as shown in Fig. 4.1.

The distance the ruler fell before being caught is recorded.

Suggest why the students work in pairs when carrying out the experiment.

Suggest three factors that need to be kept constant when carrying out the experiment.

Suggest one factor that must be kept constant when making the measurements.

The students’ results are shown in Table 4.1.

Calculate the mean distance the ruler dropped.

Give your answer to 3 significant figures.

When the students’ reaction times are measured, different parts of the nervous system are involved.

Which sequence places the parts of the nervous system in the correct order?

Tick (✓) one box.

How are nerve impulses transmitted between neurons?

Tick (✓) one box.

The students read an article about a study on the effects of alcohol on reaction time.

Scientists investigated the reaction times of two groups of adults.

The adults belonged to either a control group or an experimental group.

The different groups of adults were given a different drink, as shown in Table 4.2.

Suggest why orange drink was added to both groups’ drinks.

Suggest why 240 cm³ of the drink was given in each experiment. (ii)

The reaction times of the two groups were monitored using a computer.

Two connected lines of different length appear on the computer screen. The longer line could appear on the left or on the right.

The times when the lines appear is random. Whether the longer line is on the left or right is also random.

When the line is seen by those involved, they have to click a key for ‘left’ or ‘right’.

The time taken for a response is measured by the computer.

Give two reasons why this method of measuring reaction times gives improved results when compared to using a ruler.

Plastics are important in our everyday lives. Plastics are made of polymers.

Scientists have studied the environmental impact of plastics. They have looked at their production, use and disposal.

People do not always dispose of plastic waste carefully. This means that it can end up in the sea.

Table 5.1 shows the density of some polymers used to make plastics that pollute the sea.

The density of seawater is approximately 1025 kg / m³.

The density of pure water is 1000 kg / m³.

Which statement about the behaviour of polymers in seawater is correct?

Tick (✓) one box.

A study identified the types of plastic litter in samples of seawater.

Some of the results are shown in Table 5.2.

Draw a bar chart of the data from Table 5.2.

The samples of plastic litter were analysed and the type of polymer was identified.

The main types of polymer found are shown in the pie chart.

Which two conclusions about the main types of polymer in the plastic waste are true

Tick (✓) two boxes.

PET is the main type of polymer used for manufacturing plastic drinks’ bottles.

Describe one of the processes for recycling PET from drinks’ bottles.

PET was considered non-biodegradable.

In 2016, scientists in Japan discovered a type of bacterium living on the surface of waste PET bottles. The bacterium produces enzymes that break down the PET.

The scientists think that the bacterium may be useful in the recycling of PET.

Suggest two ways in which the bacterium might improve recycling.

The bacterium is thought to have evolved from an existing species of bacterium.

The stages in its evolution are described below.

They are not in the correct order.

A Some bacteria are able to produce enzymes to break down PET.

B Mutations occur in some bacteria.

C The altered gene spreads through the population.

D Natural selection occurs.

Put the stages in the correct order.

Complete the table below.

Parkinson’s disease is a condition that affects the nervous system. There is currently no cure for the disease.

It is estimated that 145 000 people will have Parkinson’s disease in 2018. It is predicted that by 2025 the number of people with Parkinson’s disease will rise by Calculate how many more people will have Parkinson’s disease in 2025 than in 2018.

Scientists have observed that smoking affects people’s risk of developing the disease.

The scientists investigated three groups of patients with Parkinson’s disease.

A total of 1808 patients were studied.

Discuss the findings of the study.

One hypothesis states that nicotine in cigarettes may protect against Parkinson’s disease.

People use e-cigarettes because they may be a less harmful source of nicotine.

Pure nicotine is a liquid at room temperature.

Fig. 6.1 is a simplified diagram showing how an e-cigarette works.

Describe what happens to nicotine particles in the heating chamber in an e-cigarette.

Compare the changes that occur in an e-cigarette with those in a cigarette that burns tobacco.

Which student is discussing the idea of correlation and cause?

Tick (✓) one box.

Which student has suggested a possible mechanism for the action of nicotine?

Tick (✓) one box.

* Food plants in the same family as tobacco also contain nicotine.

Scientists have studied how eating these foods affects the numbers of people with Parkinson’s disease.

People with Parkinson’s disease answered a questionnaire about their diet.

Scientists assessed the risk of developing Parkinson’s disease in people that ate plant foods containing nicotine. The results are shown in Table 6.1.

*This is the person’s risk compared with patients who ate foods containing no nicotine.

For example:

• if the risk is 2.00, you are twice as likely to get the disease

• if the risk is 0.50, you are half as likely to get the disease.

Use the information to determine if there is a correlation between eating plant foods with different concentrations of nicotine and the risk of developing Parkinson’s disease.

Use the data in Table 6.1 to support your answer.