required practical booklet q1

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Required Practical Booklet

Q1. The diagram shows a ripple tank.

(a) The motor makes a noise when it is turned on.

Describe the differences between the properties of the sound waves produced by the motor and the water waves in the ripple tank.

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(4)

(b) The period of the sound waves produced by the motor is 8.3 milliseconds.

Calculate the frequency of the sound waves.

Use the Physics Equations Sheet.

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Frequency = ____________________ Hz

(3)

(c) Explain how a student could make appropriate measurements and use them to determine the wavelength of the waves in the ripple tank.

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(6)

(Total 13 marks)

Q2. This question is about cell structures.

(a) Draw one line from each cell structure to the type of cell where the structure is found.

Cell Structure

Type of cell where the structure is

found

Nucleus Prokaryotic cells

Permanent vacuole Plant cells only

Plasmid Eukaryotic cells

(2)

(b) Figure 1 shows a plant cell.

Figure 1

What are the names of structures A, B and C?

Tick one box.

Structure A Structure B Structure C

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Chloroplast Vacuole Cell wall

Nucleus Chloroplast Cell membrane

Vacuole Mitochondrion Cell membrane

Vacuole Ribosome Cell wall

(1)

A student observed slides of onion cells using a microscope.

Figure 2 shows two of the slides the student observed.

Figure 2

The cells on the slides are not clear to see.

(c) Describe how the student should adjust the microscope to see the cells on Slide A more clearly.

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(1)

(d) Describe how the student should adjust the microscope to see the cells on Slide B more clearly.

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(2)

(e) The student made the necessary adjustments to get a clear image.

Figure 3 shows the student’s drawing of one of the cells.

Figure 3

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The real length of the cell was 280 micrometres (µm).

Calculate the magnification of the drawing.

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Magnification = × _________________________

(3)

(Total 9 marks)

Q3. A student investigated the effect of different concentrations of sugar solution on pieces of potato.

This is the method used.

1. Cut three pieces of potato to the same length. 2. Dry each piece on a paper towel. 3. Weigh each piece. 4. Place each piece in a different concentration of sugar solution. 5. Leave all three pieces for 2 hours. 6. Remove the three pieces of potato from the solutions. 7. Dry each piece on a paper towel. 8. Measure the length and mass of each piece of potato.

Figure 1 shows how the investigation was set up.

Figure 1

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(a) Why did the student dry each piece of potato before weighing it?

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(1)

(b) What two changes would you expect in the potato in tube A after 2 hours?

Tick two boxes.

Breaks into pieces

Decrease in hardness

Decrease in size

Increase in mass

Increase in length

(2)

(c) Complete the sentences.

Water moves into and out of cells by a process called ____________________ .

Water would move ____________________ the potato cells in tube A.

The solution outside the potato in tube A is at a ____________________

concentration than the solution inside the potato cells.

(3)

(d) The potato in tube B did not change.

Give one conclusion that can be made from this observation.

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(1)

(e) Figure 2 shows the root of a germinating seed.

Figure 2

Describe two ways the root is adapted to absorb water efficiently.

1. _________________________________________________________________

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2. _________________________________________________________________

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(2)

(Total 9 marks)

Q4. The figure below shows a scale drawing of one type of cell in blood.

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(a) Use the scale to determine the width of the cell.

Give your answer to the nearest micrometre.

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Width of cell = _________________ micrometres

(1)

(b) Complete the table below.

Part of the blood Function

Carries oxygen around the

body

Protects the body against

infection

Plasma

(3)

(c) Platelets are fragments of cells.

Platelets help the blood to clot.

Suggest what might happen if the blood did not clot.

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(1)

(Total 5 marks)

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Q5. This question is about photosynthesis.

(a) What are the two products of photosynthesis?

Tick two boxes.

Carbon dioxide

Chlorophyll

Glucose

Oxygen

Water

(2)

A student investigated the effect of light intensity on the rate of photosynthesis.

Figure 1 shows the apparatus.

Figure 1


1. Place the pondweed at 5 cm from the light source. 2. Measure the rate of photosynthesis by counting the number of bubbles produced in

30 seconds. 3. Repeat the investigation with the pondweed at different distances from the light

source.

(b) How could the student measure the rate of photosynthesis more accurately?

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Tick two boxes.

Count the number of bubbles produced in 1 minute

Measure the change in mass of the pondweed in 30 seconds

Measure the volume of gas produced in 30 seconds

Place the pondweed further from the light source

Use water instead of sodium hydrogencarbonate solution

(2)

(c) The LED light source does not get hot.

Why is this important?

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(1)

The table below shows the student’s results.

Distance of light source from pondweed in cm

Number of bubbles produced in 30 seconds

5 40

10 13

15 5

20 2

25 1

30 0

(d) Calculate the number of bubbles produced in 2 minutes when the light source was 10 cm from the pondweed.

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Number of bubbles produced in 2 minutes = ______________

(1)

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(e) Plot the data from the table above on Figure 2

Draw a line of best fit.

Figure 2

(3)

(f) Give one conclusion that can be made from these results.

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(1)

(Total 10 marks)

Q6. A student investigated the effect of pond organisms on the amount of carbon dioxide in their surroundings.

The student set up six boiling tubes as shown in the figure below.

They were left for 2 days.

Each boiling tube contained pond water with an indicator.

The indicator was pink at the start of the investigation.

• If the amount of carbon dioxide in the water increased the indicator turned yellow.

• If the amount of carbon dioxide in the water decreased the indicator turned purple.

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(a) What is the purpose of boiling tube A?

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(2)

(b) In which boiling tube would the indicator be the most yellow after 2 days?

Explain your answer.

Boiling tube ______________

Explanation _________________________________________________________

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(3)

(c) The colour of the indicator in boiling tube C had not changed after 2 days.

Suggest why.

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(1)

(Total 6 marks)

Q7. Neurones pass information around the body.

(a) Why are reflex reactions important?

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(1)

(b) Caffeine is a drug found in coffee.

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After a person drinks coffee information passes through neurones in the nervous system more quickly.

Suggest a hypothesis for the effect of caffeine concentration on reaction time.

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(1)

(c) Two students investigated the effect of caffeine concentration on reaction time.


1. Student A drinks a cup of coffee.

2. Student B holds a ruler above Student A’s hand.

3. Student B drops the ruler.

4. Student A catches the ruler as quickly as she can.

5. The distance the ruler falls is recorded.

Suggest how this method could be improved to produce valid results.

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(6)

(Total 8 marks)

Q8. The figure below shows an apparatus to produce elements from a solution of an ionic compound.

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(a) What is the name of the process in the figure?

Tick one box.

Combustion

Crystallisation

Distillation

Electrolysis

(1)

(b) The table below shows the products formed from three experiments using different compounds and the apparatus shown in the figure above.

Compound State Product at cathode

Product at

anode

Copper chloride

Molten Copper Chlorine

Copper chloride

Aqueous solution

Copper Chlorine

Potassium bromide

Molten Potassium Bromine

Use the table above to name the products formed at each electrode if using an aqueous solution of potassium bromide.

At cathode __________________________ At anode _______________________

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(2)

(c) Explain why copper is formed at the cathode during the electrolysis of its salts.

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(2)

(Total 5 marks)

Q9. Students used quadrats to estimate the population of dandelion plants on a field.

(a) Describe how quadrats should be used to estimate the number of dandelion plants in a field.

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(4)

(b) The field measured 40 m by 145 m.

The students used 0.25 m2 quadrats.

The students found a mean of 0.42 dandelions per quadrat.

Estimate the population of dandelions on the field.

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Estimated population of dandelions = ______________

(2)

(c) In one area of the field there is a lot of grass growing in the same area as dandelions.

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Suggest why the dandelions may not grow well in this area.

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(4)

(Total 10 marks)

Q10. This question is about making copper salts.

The figure below shows the apparatus given to a student.

Outline a safe plan the student could use to make pure, dry, crystals of the soluble salt copper sulfate from the insoluble metal oxide and dilute acid.

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(Total 6 marks)

Q11. This question is about metals and metal compounds.

(a) Copper oxide reacts with hydrochloric acid to produce copper chloride and water.

Copper oxide is insoluble in water.

Copper oxide is gradually added to hydrochloric acid until in excess.

Sketch a graph on Figure 1 to show how the pH of the hydrochloric acid would

change.

Figure 1

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(3)

(b) Magnesium reacts with hydrochloric acid to produce magnesium chloride and hydrogen.

Plan an investigation to find the accurate volume of hydrogen produced from magnesium.

You do not need to write about safety precautions.

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(6)

A student reacts different masses of copper oxide with excess zinc to produce copper.

Figure 2 shows the student’s results.

Figure 2

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(c) Calculate the gradient (slope) of the line on Figure 2.

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Gradient = ____________________ g of copper per g of copper oxide

(2)

(d) Determine the mass of copper that can be produced from 75 g of copper oxide.

Use Figure 2

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Mass = ____________________ g

(3)

(Total 14 marks)

Q12. A student investigated how length affects resistance of a wire.

Figure 1 shows the circuit the student used.

Figure 1

(a) The student took measurements using the meters X and Y.

Name meters X and Y.

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Meter X ____________________

Meter Y ____________________

(2)

The table shows the results.

Resistance in Ω

Length in m Test 1 Test 2 Test 3 Mean

0.100 0.66 0.67 0.74 0.69

0.200 1.36 1.40 1.34 1.37

0.300 2.02 2.02 2.03 2.02

0.400 2.77 2.72 2.68 2.72

0.500 3.37 3.35 3.40 3.37

0.600 4.03 4.02 3.96 4.00

(b) For which length of wire are the readings of resistance the most precise?

Give the reason for your answer.

Length = ____________________ m

Reason ____________________________________________________________

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(2)

(c) Why did the student do three tests and calculate a mean?

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(1)

(d) Write the equation that links current, potential difference, and resistance.

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(1)

(e) The potential difference across a piece of wire is 2.1 V

The current in the wire is 0.30 A

Calculate the resistance of the wire.

Write any equation that you use.

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Resistance = ____________________ Ω

(3)

Figure 2 shows a graph of the results.

Figure 2

(f) What is the label for each axis of the graph?

x-axis ______________________________________________________________

y-axis ______________________________________________________________

(2)

(g) What conclusion can be made from the graph in Figure 2?

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(1)

(Total 12 marks)

Q13. The figure below shows a paper chromatogram of five different inks.

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(a) Explain how paper chromatography separates substances.

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(3)

(b) Analyse the chromatogram. Describe and explain the result for black ink.

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(4)

(c) Use the figure above to calculate the Rf value of the blue ink.

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Rf value = ___________________________

(3)

(Total 10 marks)

Q14. A student plans a method to prepare pure crystals of copper sulfate.

The student’s method is:

1. Add one spatula of calcium carbonate to dilute hydrochloric acid in a beaker. 2. When the fizzing stops, heat the solution with a Bunsen burner until all the liquid is

gone.

The method contains several errors and does not produce copper sulfate crystals.

Explain the improvements the student should make to the method so that pure crystals of copper sulfate are produced.

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(Total 6 marks)

Q15. Some students investigated the change in temperature as sodium hydroxide solution is added to dilute sulfuric acid.


1. Put 25 cm3 of dilute sulfuric acid into a polystyrene cup.

2. Measure the initial temperature of the dilute sulfuric acid.

3. Add 4 cm3 of sodium hydroxide solution to the dilute sulfuric acid.

4. Stir the mixture.

5. Measure the highest temperature of the mixture.

6. Repeat steps 3‒5 until 40 cm3 of sodium hydroxide solution have been added.

Figure 1 shows the apparatus the student used.

Figure 1

(a) The volume of sodium hydroxide solution is a variable.

Which two words can be used to describe this type of variable?

Tick two boxes.

Categoric

Continuous

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Control

Dependent

Independent

(2)

(b) The dilute sulfuric acid has an initial temperature of 24.0 °C

Figure 2 shows the highest temperature.

Figure 2

Calculate the change in temperature.

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Temperature = ____________________ °C

(2)

Figure 3 shows the students’ results.

Figure 3

(c) Determine the volume of sodium hydroxide solution that gives the highest temperature change.

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Use Figure 3 to help you answer this question.

Volume = ____________________ cm3

(1)

(d) In Figure 3 the temperature when 16 cm3 of sodium hydroxide solution is added is anomalous.

Suggest one error that could have been made in the method which would cause this

anomalous result.

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(1)

(e) The sodium hydroxide solution in this investigation contains 80 grams per dm3

The students use 40 cm3 of sodium hydroxide solution.

Calculate the mass of sodium hydroxide in 40 cm3

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Mass = ____________________ g

(3)

(Total 9 marks)

Q16. A student wanted to determine the density of the irregular shaped object shown in Figure 1

Figure 1

(a) Plan an experiment that would allow the student to determine the density of the object.

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(6)

(b) Another student did a similar experiment.

He determined the density of five common plastic materials.

Table 1 shows the results.

Table 1

Plastic material Density in kg/m3

Acrylic 1200

Nylon 1000

Polyester 1380

Polystyrene 1040

PVC 1100

Figure 2 shows the results plotted in a bar chart.

Figure 2

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Complete Figure 2

You should:

• Write the correct scale on the y-axis. • Draw the bars for polyester, polystyrene and PVC.

(4)

(c) The student is given a piece of a different plastic material.

The student determined the density of the material three times.


Table 2

Density in kg/m3

1 960

2 1120

3 1040

Determine the uncertainty in the student’s results.

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Uncertainty = _________________ kg/m3

(2)

(Total 12 marks)

Q17. A student investigated acceleration using gliders, an air track and light gates.

The air track reduces friction between the glider and the track to zero.

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Figure 1 shows the apparatus.

Figure 1

The glider was released from rest and moved along the track.

The mass holder hit the ground before the card passed through the second light gate.

(a) Which two statements describe the effect this would have on the glider?

Tick two boxes.

Its acceleration would decrease to zero.

Its acceleration would increase.

The resultant force on it would decrease to zero.

The resultant force on it would increase.

Its speed would increase.

(2)

(b) The mass holder should not hit the ground before the card passes through the

second light gate.

Suggest one way that the student could stop this happening.

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(1)

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The student increased the resultant force acting on the glider by adding more masses to the mass holder.

She calculated the acceleration of the glider for each resultant force.

Each test was done three times.


Table 1

Resultant force in N Acceleration in m/s2

Mean acceleration in m/s2

Test 1 Test 2 Test 3

0.20 1.3 1.2 1.3 1.26667

0.39 2.6 2.5 2.6 2.6

0.59 3.8 3.8 3.9 3.8

0.78 5.1 5.1 5.1 5.1

0.98 6.4 7.2 6.4 6.7

(c) The student made two mistakes in the mean acceleration column.

Identify the mistakes the student made.

Suggest how each mistake can be corrected.

Mistake ____________________________________________________________

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Correction __________________________________________________________

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Mistake ____________________________________________________________

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Correction __________________________________________________________

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(4)

(d) Write a conclusion for this investigation.

Use the data in Table 1

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(1)

(e) The student used a constant resultant force to accelerate the glider.

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The student changed the mass of the glider and calculated the new acceleration.

She repeated this for different masses of the glider, keeping the resultant force constant.

The results are shown in Table 2

Table 2

Mass of the glider in kg

Acceleration in m/s2

0.060 3.5

0.080 2.6

0.10 2.0

0.12 1.7

0.14 1.4

Plot the results on Figure 2

Draw a line of best fit.

Figure 2

(3)

(f) Describe the relationship between mass and acceleration.

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(1)

(Total 12 marks)

Q18. A student built a circuit using filament lamps.

(a) Sketch a current potential difference graph for a filament lamp on Figure 1

Figure 1

(2)

Figure 2 shows the circuit with two identical filament lamps.

Figure 2

(b) Compare the currents I1, I2 and I3

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(2)

(c) Calculate the charge that flows through the cell in 1 minute.

Each filament lamp has a power of 3 W and a resistance of 12 Ω

Write any equations that you use.

Give the unit.

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Charge = _________________

Unit = _________________

(6)

(d) The student builds a different circuit.

Figure 3 shows the circuit.

Figure 3

Explain how the readings on both meters change when the environmental conditions change.

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(6)

(Total 16 marks)

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Mark schemes

Q1. (a) sound waves are longitudinal

1

in longitudinal waves, the oscillations / vibrations are parallel to the direction of energy transfer

allow direction that the wave is travelling for direction of energy transfer

1

water waves are transverse 1

in transverse waves, the oscillations / vibrations are at 90 degrees to the direction of energy transfer

ignore references to wave speed, wavelength or frequency

an answer stating that sound waves travel in all directions but water waves don’t is insufficient.

1

(b) 1

1

frequency = 120 (Hz)

an answer of 120(.481...) scores 3 marks

an answer of 0.12 scores 2 marks 1

(c)

Level 3: Relevant points (reasons/causes)

are identified, given in detail and logically linked to form a clear account.

5-6

Level 2: Relevant points (reasons/causes)

are identified, and there are attempts at logically linking. The resulting account is not fully clear.

3-4

Level 1: Points are identified and stated

simply, but their relevance is not clear and there is no attempt at logical thinking.

1-2

No relevant content 0

Indicative content

equipment

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• a stopclock / stopwatch should be used to time the waves

• a metre rule should be used to measure distance

determining the frequency of the waves

• the frequency could be determined by finding the time for several waves to pass a point

• the frequency could be determined by finding the how many waves pass a point in a fixed time

• frequency is the average time for one wave to pass a point

• frequency =

determining the speed of the waves

• the speed can be determined by measuring the distance travelled by a wave and the time taken to travel that distance

• the distance used to determine speed should be as long as possible

• speed = distance/time

determining the wavelength of the wave

• the wavelength can be calculated using the speed and frequency of the wave

• wavespeed = frequency × wavelength

•

•

6

[13]

Q2. (a)

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allow 1 mark for one or two correct links 2

(b)

vacuole ribosome cell wall

tick box takes precedence if no tick is given, look at both the figure and the circling of words in the table if writing is seen on the figure and in the table both must be correct

1

(c) turn the (fine focusing) knob until the cells are in focus

allow focus it

do not accept increase magnification

ignore decrease magnification ignore clear ignore references to resolution / illumination ignore zoom in / out

1

(d) (rotate the) nosepiece / objective lens

allow change the (objective / eyepiece) lens 1

to a higher power (lens)

allow (to) increase the magnification

a comparator is required

ignore change / adjust the magnification

allow stronger or more powerful lens

ignore references to resolution / illumination unqualified

ignore zoom in / out

ignore references to an electron microscope 1

(e) conversion of units: (112 mm ⟶) 112 000 (µm) or

(280 µm ⟶) 0.28 (mm) 1

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or

allow 1 mark for no conversion of units 112 / 280

or incorrect value from step 1 correctly substituted

1

400 (×)

do not accept if units are given

if no other mark scored allow 1 mark for:

a triangle with words or letters in is insufficient, as the correct rearrangement is needed

1

an answer of 400 (×) scores 3 marks

[9]

Q3. (a) any one from:

• water on potato would increase mass

allow so only the mass of the potato is measured

• to control amount of water on potato

allow to remove water from outside of potato

allow liquid / solution / sugar solution for water

allow so you get the correct (starting) mass of the potato

do not accept so that all the pieces of potato weighed the same

1

(b) increase in mass 1

increase in length 1

extra ticks negates marks

(c) osmosis

allow diffusion 1

into

allow inside do not accept through

1

lower

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allow low / more dilute / dilute 1

in this order only

(d) any one from:

• the concentration (of sugar solution) in the cells is 0.4 (mol/dm3) • the concentration (of sugar solution) in the cells is the same as the

solution (in the tube) 1

allow reference to potato instead of cells

(e) any two from:

• has (root) hairs

allow root hair cells

• large surface / area

allow wide surface area

• (root) hairs extend into soil

allow (root) hairs are long / widespread

• (root) hairs have thin walls 2

ignore references to active transport and mineral uptake

[9]

Q4. (a) 8 (micrometres)

1

(b) red blood cell(s) 1

white blood cell(s)

accept named cell

eg phagocyte / lymphocyte 1

(plasma) transports proteins / dissolved substances / food (molecules) / urea / hormones / blood cells

1

(c) any one from:

• you could lose a lot of blood • bleed internally

allow bleeding would not stop

allow could bleed to death 1

[5]

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Q5. (a) glucose

1

oxygen 1


(b) count the number of bubbles produced in 1 minute 1

measure the volume of gas produced in 30 seconds 1


(c) any one from: • to control the temperature

allow so pondweed / solution did not warm up

• temperature affects the rate of photosynthesis

allow correct description of effect of temperature on rate allow high temperatures denature enzymes

ignore references to limiting factors 1

ignore reference to ‘it’

(d) 52 1

(e) all points plotted correctly

allow ± ½ a square allow 1 mark for three points correctly plotted

2

smooth curve drawn through all points

ignore extensions of line / curve unless inconsistent with line / curve drawn

1

(where a bar chart has been plotted) allow 1 mark for all bars plotted correctly if points are plotted as well as bars, ignore bars

(f) any one from:

• the nearer the light source to the pondweed the faster the rate of photosynthesis

allow the nearer the light source to the pondweed the faster the bubbles produced

• the greater the light intensity the faster the rate of photosynthesis

allow the greater the light intensity the faster the bubbles produced

allow the closer the light source the more the plant photosynthesises

ignore more bubbles are produced with no reference to rate

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allow oxygen for bubbles

do not accept carbon dioxide 1

allow converse statements for all marking points

[10]

Q6. (a) control

1

to check that the indicator colour does not change on its own or to check any changes in colour are due to the organisms

1

(b) (tube) E 1

most carbon dioxide 1

(due to) only respiration occurring

allow no carbon dioxide used for photosynthesis

allow 1 mark max if chose tube D and give a correct reason 1

(c) the amount of carbon dioxide produced by respiration equalled amount absorbed for photosynthesis

1

[6]

Q7. (a) fast reaction to reduce / protect from harm

allow named examples 1

(b) higher caffeine concentration causes shorter reaction time.

allow converse

ignore ‘faster / slower reaction time’ 1

(c) Level 3 (5–6 marks):

A coherent method is described with relevant detail, which demonstrates a broad understanding of the relevant scientific techniques and procedures. The steps in the method are logically ordered. The method would lead to the collection of valid results.

Level 2 (3–4 marks): The bulk of a method is described with mostly relevant detail, which demonstrates a reasonable understanding of the relevant techniques and procedures. The method may not be in a completely logical sequence and may be missing some detail.

Level 1 (1–2 marks):

Discrete relevant points are made which demonstrate some understanding of the

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relevant scientific techniques and procedures. They may lack a logical structure and would not lead to the production of valid results.

0 marks:

No relevant content.

Indicative content

• use decaffeinated coffee as control • control volume of coffee • blind trial or do not tell students which coffee they are drinking • left for standard time between drink and test • at least 10 minutes • control start position of ruler • control other factors such as light in the room • same person for different concentrations • repeat for each caffeine concentration • use a range of caffeine concentrations • start with lowest concentration of caffeine • use caffeine solution instead of coffee to control for other ingredients • repeat investigation with more people and calculate means

6

[8]

Q8. (a) electrolysis

1

(b) Cathode – hydrogen 1

Anode – bromine 1

(c) copper ions are positive 1

so the copper ions are attracted to the negative cathode

allow so the copper ions gain electrons from the cathode to form copper atoms

1

[5]

Q9. (a) (placed) randomly

allow description of placement 1

sufficient number (of quadrats) used 1

count (dandelions) in each quadrat 1

use mean number of dandelions, area of quadrat and area of field to estimate population

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accept (area of field / area quadrat) × mean number of dandelions per quadrat

1

(b) (40 × 145) / 0.25 = 23 200 1

(0.42 × 23 200 =) 9744

allow 9744 with no working shown for 2 marks

allow ecf from correct attempt at the previous step) × 0.42 for 1 mark

1

(c) Level 2 (3–4 marks):

A detailed and coherent explanation is given. Logical links between clearly identified relevant points are made to explain why dandelion growth may be limited.


Discrete relevant points are made. The logic may be unclear.

0 marks: No relevant content

Indicative content

factors that may be considered: competition for resources including: • light • water • space • mineral ions (allow nutrients / salts / ions from the soil)

reference to why growth may be limited:

• (light) energy for photosynthesis • water as a raw material for photosynthesis / support • surface area exposed to light • sugar / glucose produced in photosynthesis • (space) to grow bigger • (space) for growth of root system • (mineral ions) for growth • (mineral ions / sugar) for production of larger molecules or named example

4

[10]

Q10. Level 3 (5–6 marks): A coherent method is described with relevant detail, which demonstrates a broad understanding of the relevant scientific techniques, procedures and safety precautions. The steps in the method are logically ordered with the dependent and control variables correctly identified. The method would lead to the production of valid results.


The bulk of a method is described with mostly relevant detail, which demonstrates a reasonable understanding of the relevant scientific techniques, procedures and safety precautions. The method may not be in a completely logical sequence and may be

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missing some detail.


Simple statements are made which demonstrate some understanding of some of the relevant scientific techniques, procedures and safety precautions. The response may lack a logical structure and would not lead to the production of valid results.

0 marks:

No relevant content

Indicative content

Named chemicals • copper oxide • sulfuric acid • copper sulfate

Correct use of apparatus • stirring rod • spatula • beaker • filter funnel and filter paper • evaporating basin • Bunsen burner • tripod and gauze • bench mat • conical flask

Method • add (excess) copper oxide to sulfuric acid • heat the mixture • filter the mixture • method to evaporate some of the water from the filtrate eg using a water bath

or evaporating to half volume • leave solution (to cool and) to form crystals • remove and dry crystals

Safety • wearing of safety glasses / goggles • care with use of sulfuric acid as corrosive • warming not boiling mixture of copper oxide and sulfuric acid • hold beaker containing warm mixture with tongs whilst filtering

[6]

Q11. (a)

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initial pH of hydrochloric acid is 0–3 1

pH increases as CuO is added 1

horizontal from pH = 7 (from any mass of copper oxide) 1

(b)

Level 2: The plan would lead to the production of a valid outcome. All key steps are identified and logically sequenced.

4-6

Level 1: The plan would not lead to a valid outcome. Some relevant steps are identified, but links are not made clear.

1-3


Indicative content

an ideal plan would be:

• use a rule to measure the length / use a balance to find the mass of the piece of magnesium

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• put magnesium into conical flask

• use measuring cylinder for dilute hydrochloric acid

• add dilute hydrochloric acid to conical flask

• connect bung (& delivery tube) into conical flask

• measuring cylinder is filled with water and inverted / upside down in bowl of water OR uses a gas syringe

• hydrogen flows through a delivery / rubber tube into measuring cylinder

• wait until all magnesium reacts / use excess dilute hydrochloric acid

• record volume when bubbles stop

other things they could mention:

• use accurate / 2 dp balance

• to collect gas use measuring cylinder / gas syringe with best resolution

• add bung quickly to ensure no gas escapes

• gas is collected in graduated apparatus (not test tube)

• repeat experiment (with same length / mass of magnesium)

• repeat at same temperature since volume of gas will be different

6

(c) (working)

data from candidate’s graph 1

(answer) 0.8 (g of Cu per g of CuO)

1

(d) (working on graph) extension of straight line and finding y value when x = 7.5

1

factor of ×10 1

(answer) 60 (g)

or

(using gradient) y = 0.8 x

accept ecf from question part (c)

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0.8 × 75

accept part (c) × 75

60

or

(stoichiometric method)

= 59.9 (g) 1

[14]

Q12. (a) ammeter

1

voltmeter

must be in the correct order 1

(b) 0.300 (m) 1

there is the smallest spread about the mean 1

(c) to reduce the effect of random errors 1

(d) potential difference = current × resistance

allow V = I × R 1

(e) R = V / I 1

R = 2.1 / 0.30 1

R = 7.0 Ω

an answer of 7.0 Ω scores 3 marks 1

(f) length in m 1

resistance in Ω

must be in the correct order

allow other correct labelling eg

length / m

length (m)

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allow 1 mark if units are omitted 1

(g) resistance is directly proportional to length 1

[12]

Q13. (a) mobile phase / solvent moves through paper

1

and carries substances different distances 1

which depend on their attraction for paper and solvent

allow which depend on solubility in solvent and attraction to paper

1

(b) Level 2 (3–4 marks):

A relevant and coherent description which provides a clear analysis of the chromatogram. The response makes logical links between the points raised and uses sufficient examples to support these links.

Level 1 (1–2 marks): Simple statements are made which demonstrate a basic attempt to analyse the chromatogram. The response may fail to make logical links between the points raised.

0 marks:

No relevant content

Indicative content • black ink is a mixture • because more than one spot • contains blue, red and yellow • because Rf values / positions match • does not contain green • contains an unknown • which is insoluble • yellow is most soluble or has highest Rf value, blue is least

4

(c) both measurements from artwork for 1 mark (1.3 ± 0.1 cm and 5.3 ± 0.1 cm) 1

correct equation used for 1 mark 1

0.25 ± 0.02 1

accept 0.25 ± 0.02 without working shown for 3 marks

allow ecf from incorrect measurement to final answer for 2 marks

[10]

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Q14. Level 3: Relevant points (reasons / causes) are identified, given in detail and

logically linked to form a clear account. 5−6

Level 2: Relevant points (reasons / causes) are identified, and there are attempts at

logical linking. The resulting account is not fully clear. 3−4

Level 1: Points are identified and stated simply, but their relevance is not clear and

there is no attempt at logical linking. 1−2


Indicative content

• uses sulfuric acid not hydrochloric acid or sulfuric acid needed

• uses copper carbonate / oxide not calcium carbonate or copper carbonate / oxide needed

• add solid until solid remains or is in excess or no more reacts / dissolves so that most / all of the acid reacts

• filter to remove excess or unreacted carbonate / oxide / solid

• heat gently or partially evaporate or leave until crystals appear or to crystallise

for level 3 the correct chemicals must have been selected

[6]

Q15. (a) continuous

1

independent 1

(b) 31.5 – 24.0 1

7.5 (°C)

an answer of 7.5 (°C) scores 2 marks 1

(c) 25.5 – 26(.0) cm3

1

(d) did not stir

or

did not wait long enough for the highest temperature to be reached

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1

(e) 1

× 80 1

3.2 (g)

an answer of 3.2 (g) scores 3 marks 1

[9]

Q16. (a) Level 3: The method would lead to the production of a valid outcome. All key

steps are identified and logically sequenced. 5−6

Level 2: The method would not necessarily lead to a valid outcome. Most

steps are identified, but the method is not fully logically sequenced. 3−4

Level 1: The method would not lead to a valid outcome. Some relevant steps

are identified, but links are not made clear. 1−2


Indicative content

• measure mass • use a top pan balance or scales

• part fill a measuring cylinder with water • measure initial volume • place object in water • measure final volume • volume of object = final volume − initial volume

• fill a displacement / eureka can with water • water level with spout • place object in water • collect displaced water • measuring cylinder used to determine volume of displaced water

• use of:

(b) all y-axis values correct (minimum of 3)

allow 1 mark for two correct values 2

all bars drawn to the correct height

allow 1 mark for two correct bars

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allow ± ½ small square 2

(c)

ignore + and / or − signs 1

= 80 (kg/m3)

an answer of 160 scores 1 mark 1

an answer of 80 scores 2 marks

[12]

Q17. (a) its acceleration would decrease to zero

1

the resultant force on it would decrease to zero 1

(b) any one from: • move the second light gate closer to the first • shorten the string length

allow use a taller table 1

(c) 1.26667 (m/s2) (is wrong)

allow (mean value calculated at) 0.20 (N) 1

give value to 2 significant figures

allow give value to 1 decimal place allow 1.3 (m/s2)

1

6.7 (m/s2) (is wrong)

allow (mean value calculated at) 0.98 (N) allow test 2 for 0.98 (N) or 7.2 is an anomaly

1

discard the anomalous result and recalculate the mean

allow repeat the anomalous test result and re-calculate the mean allow 6.4 (m/s2)

1

each mistake and its correction may be given in any order

(d) (resultant) force is directly proportional to acceleration

allow the larger the (resultant) force, the greater the acceleration

allow positive correlation between (resultant) force and acceleration

allow mass / weight (of the holder) for (resultant)

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force 1

(e) all points correctly plotted within ½ small square

allow 1 mark for 3 or 4 points correctly plotted 2

curved line of best fit 1

(f) inversely proportional

allow as mass increases, acceleration decreases 1

[12]

Q18. (a) a curve in the first and third quadrants only, passing through origin

1

decreasing gradient 1

(b) any two from:

• I1 = I2 + I3

• I2 = I3

• I1 = 2I2

• I1 = 2I3

allow 1 mark for each correct description given in words

2

(c) 3 = I2 × 12 1

1

I = 0.5 (A) 1

Q = 0.5 × 60 = 30

allow Q = their calculated I × 60

1

Qtotal = 60

allow an answer that is consistent with their calculated value of I

1

or

3 = I2 × 12 (1)

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I = 0.5 (A) (1)

Itotal = 1.0 (A) (1)

allow Itotal = their I × 2

Q = 1.0 × 60 = 60 (1)

allow an answer that is consistent with their calculated value of I

coulombs or C 1

an answer of 60 scores 5 calculation marks

(d) Level 3: Relevant points (reasons / causes) are identified, given in detail and logically linked to form a clear account.

5−6

Level 2: Relevant points (reasons / causes) are identified, and there are

attempts at logically linking. The resulting account is not fully clear. 3−4

Level 1: Points are identified and stated simply, but their relevance is not clear and there is no attempt at logical linking.

1−2


Indicative content

• resistance of LDR changes when light intensity changes • when light intensity increase resistance of LDR decreases

• overall resistance of circuit decreases • potential difference across total resistance remains unchanged • current in ammeter increases

• potential difference across fixed resistor increases • potential difference across LDR decreases • reading on the voltmeter decreases

• potential difference is shared between the components in series • the lower the resistance of the LDR the smaller the share of the potential

difference • reading on the voltmeter decreases

[16]

required practical booklet q1

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