AQA GCSE Synergy Paper 3: Physical sciences Higher June 2024 question paper 8465/3H

Enzymes are large molecules and biological catalysts.

What type of molecule is an enzyme?

A catalyst changes the rate of a chemical reaction.

What happens to the mass of a catalyst during a chemical reaction?

Tick (✓) one box.

The mass of the catalyst decreases.

The mass of the catalyst stays the same.

The mass of the catalyst increases.

Figure 1 shows a model of enzyme action.

Name X and Y in Figure 1.

Name the model shown in Figure 1.

Amylase is an enzyme that breaks down starch.

A student investigated how changing the pH affected the activity of amylase.

This is the method used.

1. Heat a test tube containing 2 cm³ of amylase solution at pH 5.0 in a water bath at 35 °C.

2. Heat a test tube containing 2 cm³ of starch solution in the same water bath.

3. Transfer the amylase solution into the test tube of starch solution and mix.

4. After 30 seconds remove a drop of the amylase–starch mixture and test the drop for starch.

5. Repeat step 4 until no starch is detected.

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

7. Repeat steps 1 to 6 using amylase solution at different pH values.

Explain why the solutions are all placed in the same water bath.

Describe the test for starch.

Give the result of the test if starch is present.

Table 1 shows the results.

Which range of pH values had the fastest rate of reaction?

Tick (✓) one box.

pH 5.0 to pH 5.5

pH 6.0 to pH 6.5

pH 7.0 to pH 7.5

pH 8.0 to pH 8.5

How could the method be improved to obtain a more accurate pH value for the fastest rate of reaction?

Figure 2 shows a velocity–time graph for a remote-controlled car.

Determine the acceleration of the car between 0 and 20 seconds.

Use the Physics Equations Sheet.

Determine the distance travelled by the car between 20 seconds and 45 seconds.

Use the Physics Equations Sheet.

How does the deceleration of the car compare with the acceleration of the car?

Use Figure 2.

Give one reason for your answer.

Tick (✓) one box.

The deceleration was greater than the acceleration.

The deceleration was the same as the acceleration.

The deceleration was less than the acceleration.

A student investigated the reaction between citric acid powder and sodium hydrogen carbonate solution.

The temperature of the reaction mixture decreased.

The reaction between citric acid and sodium hydrogen carbonate is endothermic.

Which reaction profile represents an endothermic reaction?

Tick (✓) one box.

Explain why the rate of reaction is greater when powder is used instead of larger lumps.

Refer to surface area and collisions in your answer.

This question is about life cycle assessments (LCAs).

LCAs assess the environmental impact of different processes during the life cycle of a product.

Table 2 shows values for the environmental impact of three processes during the production of two shirts.

The environmental impacts were measured in different units.

The measurements were converted to values with the same units.

These units are known as equivalent units.

Give one reason why equivalent units are used in LCAs.

Evaluate the environmental impact of producing shirt A compared with producing shirt B.

Use Table 2.

Use calculations in your answer.

Peer reviews are used to check LCAs.

Why should an independent scientist be used to peer review an LCA?

Some LCAs assess the environmental impact of metal extraction.

Name the biological methods of metal extraction that use:

bacteria

plants.

Figure 3 shows how the National Grid links a nuclear power station to consumers.

Explain why step-up transformers are used in the National Grid.

Explain why step-down transformers are used in the National Grid.

Figure 4 shows a transformer.

The potential difference across the primary coil is 345 kV.

The potential difference across the secondary coil is 230 V.

The current in the primary coil is 0.060 A.

Calculate the current in the secondary coil.

Use the Physics Equations Sheet.

Nuclear power stations and coal power stations have an environmental impact.

Compare the environmental impact of generating electricity using these two types of power station.

This question is about groups in the periodic table.

What name is given to the Group 0 elements?

Explain the reactivity of the Group 0 elements.

Describe the relationship between relative atomic mass and boiling point for the elements in Group 0.

Fluorine is an element in Group 7.

Complete Figure 5 to represent the electronic structure of fluorine.

Which is a correct statement about the elements in Group 7?

Tick (✓) one box.

The elements in Group 7 consist of single, non-bonded atoms.

The elements in Group 7 react with non-metals to form covalent compounds.

The melting points of the elements in Group 7 decrease going down the group.

The reactivity of the elements in Group 7 increases going down the group.

The elements in Group 1 react with water.

Give two observations you would see when a small piece of lithium is added to water.

Lithium reacts with water less vigorously than sodium reacts with water.

Explain why lithium is less reactive than sodium.

Complete the equation for the reaction of lithium with water.

You should balance the equation.

Magnesium reacts with oxygen to form magnesium oxide.

Describe what happens when a magnesium atom reacts with an oxygen atom to produce magnesium oxide.

A student reacted different masses of magnesium with oxygen.

The student determined the mass of magnesium oxide produced.

Table 3 shows the results.

Complete Figure 6.

You should:

use a suitable scale for the y-axis

plot the data from Table 3.

The first point has been plotted for you.

The student’s results cannot be used to show that the method gives precise measurements.

Give one reason why.

Figure 7 shows two people wearing inflatable bodysuits.

The bodysuits are made of soft plastic and are inflated with air.

The bodysuits reduce the chance of injury in a collision.

Explain how wearing a bodysuit reduces the chance of injury in a collision.

Figure 8 shows person A about to collide with person B.

The arrows show the direction in which each person is moving.

The velocity of person A is + 2.0 m/s.

The two people collide and stop.

Calculate the velocity of person B before the collision.

Use the Physics Equations Sheet.

Figure 9 shows a person in an inflatable sphere rolling down a hill.

The total mass of the person and sphere is 80 kg.

The sphere moves through a vertical height of 6.4 m.

gravitational field strength = 9.8 N/kg

Calculate the maximum possible speed of the sphere at the bottom of the hill.

Use the Physics Equations Sheet.

The actual speed of the sphere at the bottom of the hill is much less than the maximum possible speed.

Explain why.

This question is about hydrocarbons.

Hexane (C₆H₁₄) and pentane (C₅H₁₂) are hydrocarbons in the same homologous series.

Give the name of the homologous series that includes hexane and pentane.

Give the general formula of the homologous series that includes hexane and pentane.

Explain why the boiling point of hexane is higher than the boiling point of pentane.

Complete the equation for the cracking of hexane (C₆H₁₄) into ethene and one other molecule.

Methane undergoes complete combustion with oxygen.

Figure 10 represents the equation for the reaction.

Figure 10

The energy released forming the new bonds is 814 kJ/mol greater than the energy needed to break the existing bonds.

Table 4 shows some bond energy values.

Calculate value Y in Table 4.

_ Y = ____________________ kJ/mol