AQA GCSE Synergy Paper 3: Physical sciences Foundation November 2020 question paper 8465/3F

This question is about elements.

Figure 1 shows the chemical symbols of five elements in the periodic table.

Which element is a noble gas?

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Which element forms fullerenes?

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Which two elements have atoms with the same number of electrons in their outer shell?

Use Figure 1.

Argon is very unreactive.

Figure 2 represents the electronic structure of an argon atom.

How does the electronic structure show that argon is unreactive?

Figure 3 shows some of the elements in Group 7 of the periodic table.

Chlorine gas consists of molecules.

What is the formula of a chlorine gas molecule?

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Which Group 7 element is the most reactive?

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Lithium atoms react with bromine atoms to produce lithium bromide.

Lithium bromide contains lithium ions and bromide ions.

Figure 4 shows the electronic structure of the atoms and ions.

The symbols (o) and (x) represent electrons.

Only the outer shell electrons are shown.

Describe what happens when a lithium atom reacts with a bromine atom to produce a lithium ion and a bromide ion.

Figure 5 shows a car travelling at a constant speed on a straight, level road.

Draw an arrow on Figure 5 to show the direction of the force of air resistance on the car.

The mass of the car is 850 kg

Calculate the weight of the car.

Use the equation:

weight = mass × gravitational field strength

gravitational field strength = 9.8 N/kg

What is the direction of the normal contact force of the road on the wheels?

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The car is travelling at constant speed.

The resultant force on the car is zero.

How does the size of the normal contact force of the road on the wheels compare with the weight of the car?

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A car is travelling at a constant speed.

A constant braking force of 5100 N is applied by the brakes.

The car decelerates and stops.

The braking distance is 38 m

Calculate the work done by the braking force.

Choose the unit from the box.

Use the equation: work done = force × distance

Which two factors affect braking distance?

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The distance a car travels during the driver’s reaction time is called the thinking distance.

Which factor affects thinking distance?

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Figure 6 shows a sketch graph of how thinking distance varies with speed.

Which term describes the relationship between thinking distance and speed?

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Figure 7 shows part of the magnetic field around a bar magnet.

Figure 7

Complete Figure 7 to show the magnetic field around the bar magnet.

You should:

• draw one more magnetic field line

• show the direction of the magnetic field.

A student made an electromagnet from a metal nail and a coil of wire.

Figure 8 shows the electromagnet held in a clamp and connected to a circuit.

When the switch was closed, the electromagnet attracted paper clips.

Which metal should be used for the nail?

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The student varied the number of turns of wire around the nail.

The student recorded how many paper clips the electromagnet could hold.

Table 1 shows the results.

Predict value X in Table 1.

The student increased the resistance of the variable resistor.

What is the circuit symbol for a variable resistor?

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Complete the sentences.

Choose answers from the box.

Each answer may be used once, more than once or not at all.

When the resistance of the variable resistor was increased, the current in

the electromagnet.

When the resistance of the variable resistor was increased, the number of paper

clips the electromagnet could hold.

Figure 9 shows an electromagnet being used at a scrapyard.

Give two advantages of using an electromagnet to sort scrap metal compared with using a permanent magnet.

Crude oil is a mixture containing hydrocarbons.

Alkanes are hydrocarbons.

Figure 10 represents an alkane.

X and Y represent atoms of different elements in an alkane.

Label element X and element Y on Figure 10.

What is represented by Z on Figure 10 ?

Crude oil is separated into fractions in a fractionating column.

Figure 11 shows a fractionating column.

Table 2 gives some properties of different fractions separated from crude oil.

Label Figure 11 to show where diesel, heavy fuel oil and kerosene fractions are collected.

Use Table 2.

Complete the sentences.

Choose answers from the box.

Which statement about the flammability of petrol and diesel is correct?

Use Table 2.

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Table 2 is repeated here.

Octane is a hydrocarbon obtained from crude oil.

Octane has 8 carbon atoms.

Which fraction in Table 2 contains octane?

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Name the two substances produced from the complete combustion of octane.

One use of carbon dioxide is in fizzy drinks.

In fizzy drinks carbon dioxide gas dissolves in water to form an aqueous solution of

The equation for the reaction is:

Complete the equation by writing the state symbol for carbonic acid (H₂CO₃).

Choose the answer from the box.

Which ion causes carbonic acid to be acidic?

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Describe how to test the pH of carbonic acid.

Give the result of the test.

Ammonia gas is produced from nitrogen gas and hydrogen gas in a reversible reaction.

The word equation is:

nitrogen + hydrogen ammonia

Figure 12 represents an ammonia molecule.

What is the formula of ammonia?

When does a reversible reaction reach dynamic equilibrium?

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Which condition is needed for the reversible reaction between nitrogen and hydrogen to be at dynamic equilibrium?

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How can the direction of a reversible reaction be changed?

Iron is used as a catalyst in the industrial production of ammonia.

Why is a catalyst used?

150 000 million kg of ammonia is produced each year.

85% of the ammonia produced each year is used to manufacture fertilisers.

Calculate the mass of ammonia used each year to manufacture fertilisers.

A student investigated the effect of pH on the rate of starch digestion.

This is the method used.

1. Add 2 cm³ of amylase solution at pH 5.0 to a test tube.

2. Add 2 cm³ of starch solution to the same test tube.

3. Start the timer.

4. Remove one drop of the amylase-starch mixture after 30 seconds.

5. Test the drop for starch.

6. Remove a drop of the amylase-starch mixture every 30 seconds until no starch is detected.

7. Record the total time taken for no starch to be detected.

8. Repeat steps 1 to 7 using amylase solution at different pHs.

The student kept all the solutions in a water bath at 37 °C

What is the independent variable in the investigation?

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Describe the test for starch.

Give the result of the test if starch is present.

Table 3 shows the results.

What is the pH range the student used?

Use Table 3.

At the optimum pH the enzyme works fastest.

What is the optimum pH for amylase enzyme?

Use Table 3.

How could the investigation be improved to get a more accurate value for the optimum pH?

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What is the best way for the student to display the results?

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Some street lights automatically switch on when it gets dark.

Figure 13 shows a street light.

The electrical circuit for the street light includes a light-dependent resistor (LDR).

The power supply for the street light uses alternating current.

What is alternating current?

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Figure 14 shows how the resistance of the LDR varies with light intensity.

Light intensity is measured in lux

How does light intensity affect the resistance of the LDR?

Write down the equation which links current (I), potential difference (V) and resistance (R).

The potential difference across the LDR is 30 V

The current in the LDR is 0.05 A

Calculate the resistance of the LDR.

Determine the light intensity incident on the LDR.

Use your answer to Question 07.4 and Figure 14.

This street light may stay switched on when it is not dark.

What is the most likely cause of this problem?

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This street light is replaced with one which is more efficient.

What does more efficient mean?

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A student investigated how the power output of a filament lamp varied with the current in the lamp.

Figure 15 shows part of the circuit the student used.

To calculate power output the student measured the current in the lamp and the potential difference across the lamp.

Complete Figure 15 by adding an ammeter and a voltmeter to make the measurements.

Use the correct circuit symbols.

Which energy store in the battery decreases when the lamp is switched on?

What happens to the energy transferred by the lamp?

Figure 16 shows the results.

Describe how varying the current affects the power output of the filament lamp.

Write down the equation which links current (I), power (P) and resistance (R).

Determine the resistance of the lamp when the current in the lamp is 0.22 A

A student investigated the temperature increase when magnesium powder was added to copper sulfate solution.

Figure 17 shows the apparatus used.

This is the method used.

1. Add copper sulfate solution to a beaker.

2. Measure the initial temperature of the copper sulfate solution.

3. Add 0.1 g of magnesium powder.

4. Stir the mixture.

5. Measure the maximum temperature of the mixture.

6. Repeat steps 1 to 5 with different masses of magnesium powder.

Give two control variables the student should use.

Suggest one change to improve the accuracy of the investigation.

Table 4 shows the student’s results.

Explain the conclusions that can be made from the trends shown in the results.

Use data from Table 4 in your answer.

This question is about iron and steel.

Figure 18 shows a flow chart for the production of iron and steel from iron ore.

Iron ore consists mainly of iron oxide.

In the blast furnace iron oxide reacts with carbon monoxide to form iron and carbon dioxide.

Complete the equation for the reaction between iron oxide and carbon monoxide.

You should balance the equation.

Iron oxide is reduced in the reaction with carbon monoxide.

What does ‘reduced’ mean in this reaction?

Cast iron is an alloy.

Cast iron contains carbon.

Figure 19 shows the arrangement of atoms in pure iron and in cast iron.

Explain why cast iron is harder than pure iron.

In addition to cast iron, scrap steel is added to the steel-making furnace.

Give three environmental advantages of recycling scrap steel in this way.