Year 10 Paper 5: Skills Practice
Covers cell biology, organisation, bonding, energy and electricity.
Year 10 here means a typical teaching order, not a syllabus rule. No exam board defines what belongs to Year 10, and schools sequence the course differently. Check it against your own scheme of work before using it to decide what a class has covered.
Questions
Question 1 [5 marks]
Bonding, Structure and the Properties of Matter
A sample of poly(ethene) contains chains that are, on average, made from 500 repeating -CH2-CH2- monomer units.
The relative formula mass of one -CH2-CH2- unit is 28.
Calculate the average relative molecular mass of a poly(ethene) chain in this sample, and explain why this value is described as an average.
Question 2 [5 marks]
Organisation
A sample of blood has a total volume of 5.0 cm^3.
The sample contains 2.2 cm^3 of red blood cells, white blood cells and platelets, and the rest of the sample is plasma.
Calculate the percentage of the blood sample's volume that is plasma.
Question 3 [5 marks]
Cell Biology
A student investigates the effect of hydrogen peroxide concentration on the rate of the reaction catalysed by catalase in celery extract, measuring the volume of oxygen gas produced in 60 seconds.
Using 1% hydrogen peroxide, 18 cm^3 of oxygen gas is collected in 60 seconds. Using 3% hydrogen peroxide, 54 cm^3 of oxygen gas is collected in 60 seconds.
Calculate the percentage increase in the rate of reaction caused by using the higher concentration of hydrogen peroxide.
Question 4 [5 marks]
Bonding, Structure and the Properties of Matter
A human hair has a diameter of about 0.08 mm. A silver nanoparticle used in a sports sock has a diameter of 20 nm.
Calculate how many of these nanoparticles, placed side by side, would span the diameter of the human hair.
Question 5 [6 marks]
Organisation
The heart has four chambers: the left atrium, right atrium, left ventricle and right ventricle.
Explain why the wall of the left ventricle is thicker and more muscular than the wall of the right ventricle.
Question 6 [5 marks]
Cell Biology
A single-celled organism can be modelled as a cube with sides of length 2 mm.
Calculate the surface area to volume ratio of the organism, and explain why a small size is important for this organism to survive by relying on diffusion alone for exchanging substances.
Question 7 [6 marks]
Electricity
Electrical power is transmitted across the National Grid at a very high voltage, stepped up by transformers before transmission and stepped down again before reaching homes.
Explain why transmitting electrical power at a high voltage (and correspondingly low current) reduces the amount of energy wasted during transmission.
Question 8 [5 marks]
Cell Biology
A student places identical potato chips into salt solutions of different concentrations to investigate osmosis.
One potato chip has a mass of 5.20 g before the experiment. After 24 hours in a 0.4 mol/dm^3 salt solution, the potato chip has a mass of 4.68 g.
Calculate the percentage change in mass of the potato chip, and state whether this is an increase or a decrease. Give your answer to 1 decimal place.
Question 9 [6 marks]
Bonding, Structure and the Properties of Matter
Sodium chloride is an ionic compound with a giant ionic lattice structure.
Explain why solid sodium chloride does not conduct electricity, but molten sodium chloride and an aqueous solution of sodium chloride both conduct electricity.
Question 10 [6 marks]
Electricity
A thermistor is connected in series with a fixed resistor to form a potential divider circuit, used to detect a change in temperature.
Explain, in terms of the thermistor's resistance, how the potential difference across the fixed resistor changes as the temperature increases.
Question 11 [6 marks]
Energy
A 1.5 kg block of an unknown metal is heated from 20 degrees C to 95 degrees C using 87750 J of energy.
Calculate the specific heat capacity of the metal, in J/kg degrees C. Use change in thermal energy = m c (change in temperature).
Model solutions
| Question 1[5 marks] | |
|---|---|
| Answer or working | Marks |
| using total mass = number of units x mass per unit | M1 |
| substituting 500 x 28 | M1 |
| 14000 | A1 |
| explaining that different polymer chains in the same sample have different lengths (numbers of monomer units) | B1 |
| stating this means the sample contains molecules of different relative molecular mass, so an average value is used to describe the whole sample | B1 |
| Final answer: 14000; different chains in a polymer sample have different lengths, so an average relative molecular mass is used to describe the whole sample | |
| Question 2[5 marks] | |
|---|---|
| Answer or working | Marks |
| plasma volume = 5.0 - 2.2 | M1 |
| 2.8 cm^3 | A1 |
| using percentage = (plasma volume / total volume) | M1 |
| substituting (2.8 / 5.0) x 100 | M1 |
| 56% | A1 |
| Final answer: 56% of the blood sample's volume is plasma | |
| Question 3[5 marks] | |
|---|---|
| Answer or working | Marks |
| finding the rate with 1% hydrogen peroxide, 18 / 60 = 0.3 cm^3 per second | M1 |
| finding the rate with 3% hydrogen peroxide, 54 / 60 = 0.9 cm^3 per second | M1 |
| finding the increase in rate, 0.9 - 0.3 = 0.6 cm^3 per second | M1 |
| (0.6 / 0.3) x 100 | M1 |
| 200% | A1 |
| Final answer: 200% increase in the rate of reaction | |
| Question 4[5 marks] | |
|---|---|
| Answer or working | Marks |
| converting 0.08 mm to nm, 0.08 x 1000000 | M1 |
| 80000 nm | A1 |
| number of nanoparticles = 80000 / 20 | M1 |
| 4000 | A1 |
| stating this shows nanoparticles are far too small to see with the naked eye or a standard optical microscope | B1 |
| Final answer: 4000 nanoparticles; this shows nanoparticles are far too small to see with the naked eye or a standard optical microscope | |
| Question 5[6 marks] | |
|---|---|
| Answer or working | Marks |
| the left ventricle pumping blood around the whole body (the systemic circulation) | B1 |
| the right ventricle only pumping blood to the lungs (the pulmonary circulation), a much shorter distance | B1 |
| blood needing to be pumped at a higher pressure to reach the whole body than to reach only the lungs | B1 |
| the left ventricle therefore needing to contract with more force than the right ventricle | B1 |
| a thicker, more muscular wall allowing the left ventricle to contract with greater force | B1 |
| this generating the higher pressure needed to pump blood all the way around the body | B1 |
| Final answer: The left ventricle pumps blood around the whole body, much further than the right ventricle pumps to the lungs, so it needs a thicker wall to generate higher pressure | |
| Question 6[5 marks] | |
|---|---|
| Answer or working | Marks |
| surface area = 6 x 2^2 | M1 |
| volume = 2^3 | M1 |
| a surface area to volume ratio of 3 (or 3:1) | A1 |
| stating a small size gives the organism a large surface area to volume ratio | B1 |
| stating this allows enough substances to diffuse in and out to meet the organism's needs without a transport system | B1 |
| Final answer: Surface area to volume ratio of 3; a small size gives a large SA:V ratio, so diffusion alone can meet the organism's needs | |
| Question 7[6 marks] | |
|---|---|
| Answer or working | Marks |
| stating that for a given amount of power transmitted, increasing the voltage means a smaller current is needed, since power = current x voltage | B1 |
| stating some energy is wasted as heat in the transmission cables because of their resistance | B1 |
| stating the power wasted as heat depends on the current squared, since power wasted = current^2 x resistance | B1 |
| stating a smaller current therefore wastes much less power as heat, in the same cables | B1 |
| stating this makes transmission at high voltage and low current much more efficient than at low voltage and high current | B1 |
| stating step-up transformers increase the voltage for transmission, and step-down transformers reduce it again to a safe level for homes | B1 |
| Final answer: High voltage means a lower current for the same power (P = IV), and since heat loss depends on current squared (P = I^2 R), a lower current wastes much less energy as heat in the cables | |
| Question 8[5 marks] | |
|---|---|
| Answer or working | Marks |
| finding the change in mass, 4.68 - 5.20 = -0.52 g | M1 |
| dividing the change in mass by the original mass | M1 |
| multiplying by 100 | M1 |
| -10.0% | A1 |
| stating this is a decrease (loss of mass) | B1 |
| Final answer: -10.0% (a decrease in mass) | |
| Question 9[6 marks] | |
|---|---|
| Answer or working | Marks |
| solid sodium chloride having ions held in fixed positions in a rigid lattice | B1 |
| stating the ions cannot move to carry an electric charge in the solid | B1 |
| stating solid sodium chloride therefore does not conduct electricity | B1 |
| the rigid lattice breaking down when the compound is molten, so the ions are free to move | B1 |
| the ions separating and also being free to move when the compound is dissolved in water | B1 |
| stating these free-moving, charged ions can carry an electric current, so molten or dissolved sodium chloride conducts electricity | B1 |
| Final answer: Ions are fixed in place in solid NaCl so cannot carry charge; when molten or dissolved the ions are free to move and can carry an electric current | |
| Question 10[6 marks] | |
|---|---|
| Answer or working | Marks |
| the resistance of a thermistor decreasing as its temperature increases | B1 |
| stating that in a series circuit, the current increases if the total resistance decreases, for a fixed supply voltage | B1 |
| stating the current through the circuit therefore increases as the temperature increases | B1 |
| stating the potential difference across the fixed resistor is proportional to the current through it, since its resistance is constant | B1 |
| stating the potential difference across the fixed resistor therefore increases as the temperature increases | B1 |
| stating this changing potential difference can be used by additional circuitry to trigger a response, such as switching on a cooling fan | B1 |
| Final answer: As temperature rises, the thermistor's resistance falls, so the circuit current rises and the potential difference across the fixed resistor increases, which can trigger a response like a fan switching on | |
| Question 11[6 marks] | |
|---|---|
| Answer or working | Marks |
| finding the temperature change, 95 - 20 = 75 degrees C | M1 |
| rearranging to c = E / (m x change in temperature) | M1 |
| substituting 87750 / (1.5 x 75) | M1 |
| evaluating 1.5 x 75 = 112.5 | M1 |
| 780 J/kg degrees C | A1 |
| stating this value could be used to identify the metal, by comparing it to known specific heat capacities | B1 |