Question 1:-
(a) Fig. 1.1 is a diagram of the female reproductive system in humans
State which letter in Fig. 1.1 identifies where:
meiosis occurs ……………..
fertilisation occurs ……………..
implantation occurs. ……………..
(b) Fig. 1.2 is a diagram showing some of the processes involved in the formation of a human embryo.
(i) State the number and describe the arrangement of chromosomes in cell Z in Fig. 1.2.
number of chromosomes ……………………………………..
arrangement of chromosomes ………………………………..
(ii) State the sex chromosomes in human females.
(iii) State the name of the adaptive feature of egg cells that changes after fertilisation to prevent entry of more than one sperm.
(c) State one function of the amniotic fluid.
(d) Tick (✓) all the boxes that show correct statements about the placenta.
▶️Answer/Explanation
Ans :
1(a) B ;
A ;
E ;
1(b)(i) 46 chromosomes ;
arranged in pairs ;
1(b)(ii) XX ;
1(b)(iii) jelly coat ;
1(c) shock absorber / protection (from mechanical harm/infection of fetus) / stabilises temperature ;
1(d)
Question 2:-
(a) Magnesium sulfate contains magnesium ions, Mg2+, and sulfate ions, \( SO_{4}^{2-}\) .
(i) Determine the formula of magnesium sulfate.
formula = …………………………………………………
(ii) Explain why solid magnesium sulfate cannot conduct electricity but solid magnesium can conduct electricity.
(b) Magnesium reacts with hydrochloric acid, HCl.
Magnesium chloride, MgCl2, and hydrogen gas are made.
(i) Describe the test for hydrogen gas and the observation for a positive result.
test …………………………………………………………………………………
observation ……………………………………………………………………..
(ii) Calculate the mass of magnesium chloride made when 1.2g of magnesium reacts with excess hydrochloric acid.
Mg + 2HCl → MgCl2 + H2
[Ar : Cl, 35.5; H, 1; Mg, 24]
(iii) The ionic equation for this reaction is shown.
Mg + 2H+ → Mg2+ + H2
Explain why this reaction is described as a redox reaction.
▶️Answer/Explanation
Ans :
2(a)(i) MgSO4 ;
2(a)(ii) magnesium:
idea that magnesium has electrons ;
(electrons) can move ;
magnesium sulfate:
idea of that ions are held in fixed positions (in a solid) ;
2(b)(i) test – lighted splint ;
result – (squeaky) pop ;
2(b)(ii) relative molecular mass of MgCl2 = 95 ;
\(\frac{9.5 \times 1.2}{24} =4.8(g)\)
2(b)(iii) EITHER
Mg/magnesium is oxidised ;
H+ / hydrogen ions are reduced ;
OR
the Mg / magnesium atoms lose electrons ;
H+ / hydrogen ions gain electrons ;
Question 3:-
Fig. 3.1 shows apparatus called a ripple tank.
This is used to investigate water waves.
An electric motor causes the board to vibrate.
At a constant speed of rotation, the motor produces waves at a constant rate.
(a) The electric motor causes the vibrating board to move up and down at a known frequency.
This produces water waves with the same frequency.
(i) State the meaning of the term frequency.
(ii) The ripple tank produces waves with a frequency of 5.0Hz which travel at a speed of 0.20m/s.
Calculate the wavelength of the water waves.
wavelength = ……………………… m
(iii) Describe how the diffraction of water waves is demonstrated using a ripple tank.
Include a description of what is observed.
You may draw a diagram to help with your answer.
(b) The ripple tank uses a simple d.c. motor.
Complete the sentences to explain how the motor rotates.
The current‑carrying coil experiences a force because it is in a …………………………………. field.
The force on one side of the coil is upwards and the force on the other side of the coil is …………………………………., causing a turning effect.
(c) The ripple tank uses a filament lamp during the demonstration.
(i) Draw the circuit symbol for a filament lamp.
(ii) The potential difference across the filament lamp is 12V.
During the demonstration, the filament lamp uses 24000J of electrical energy.
Calculate how much charge passes through the filament lamp during the demonstration.
State the unit of your answer.
charge = …………………………. unit ……………..
▶️Answer/Explanation
Ans :
3(a)(i) number of vibrations / oscillations (generated / passing a point) per unit time / second ;
3(a)(ii) ( λ=) v/f OR 0.20/5.0 ;
(λ=) 0.04 ;
3(a)(iii) place an obstacle with a gap (with a size similar to the wavelength) in the ripple tank ;
circular waves produced after the gap ;
3(b) magnetic ;
downwards ;
3(c)(i)
3(c)(ii) E = IVt OR 24000 = 12 × It OR It = 24000 / 12 ;
Q = It ;
Q = 2000 ;
C OR coulomb ;
Question 4:-
(a) A student investigates the effect of temperature on the rate of transpiration.
Transpiration is estimated by recording the loss in mass.
The student keeps one plant at 20°C and one plant at 40°C.
The student records the mass of each plant every day for 5 days.
Fig. 4.1 shows the apparatus the student uses.
Fig. 4.2 is a graph of the results.
(i) Complete the sentences to describe and explain the results shown in Fig. 4.2.
The mass of the plant kept at 40°C decreased in mass by …………………g between day 1 and day 5.
As temperature increases, the water molecules gain more ……………………. energy.
This increases the rate of evaporation from the surfaces of the …………….. cells.
There is also an increase in the rate of diffusion of ………………. through the ………………… into the atmosphere.
(ii) State how an increase in humidity would affect the results shown in Fig. 4.2.
(b) Water is transported to the leaves by xylem.
(i) State how the water molecules are held together in the xylem.
(ii) State one other function of xylem, apart from transport.
(iii) State the name of one other transport tissue in plants.
▶️Answer/Explanation
Ans :
4(a)(i) 62 (g) ;
kinetic ;
(spongy) mesophyll ;
water vapour ;
stomata ;
4(a)(ii) (both plants) would lose less mass ;
4(b)(i) cohesion ;
4(b)(ii) support ;
4(b)(iii) phloem ;
Question 5:-
(a) Fig. 5.1 shows part of the structure of lithium chloride.
(i) Deduce the formula of lithium chloride.
formula = ………………………………
(ii) Lithium chloride has a high melting point of 605°C.
Explain why lithium chloride has a high melting point.
(b) Fig. 5.2 shows part of the structure of graphite.
(i) Describe the structure of graphite.
(ii) Explain why graphite is used as a lubricant.
Use ideas about structure and bonding.
(c) Mercury is a liquid at room temperature, 25°C.
(i) Tick (✓) the row in Table 5.1 which shows the melting point and boiling point of mercury.
(ii) Mercury has a proton number (atomic number) of 80 and a nucleon number (mass number) of 201.
Complete Table 5.2 for an atom of mercury.
▶️Answer/Explanation
Ans :
5(a)(i) LiCl ;
5(a)(ii) idea that lithium chloride has (strong electrostatic) forces of attraction / bonds between (oppositely charged) ions ;
idea that the forces / bonds need lots of energy to overcome ;
5(b)(i) Any two from:
giant covalent ;
layers (of carbon atoms) ;
each carbon atom is (covalently) bonded / joined to 3 other (carbon) atoms ;
5(b)(ii) idea that there are weak forces between the layers (of carbon atoms) ;
(so) the layers can slide ;
5(c)(i) –39 and 357 √;
5(c)(ii)
Question 6:-
Fig. 6.1 shows a canister filled with liquid chlorine under pressure.
When the chlorine is released from the canister, it turns into a gas.
(a) (i) Describe the arrangement and separation of molecules in a liquid and molecules in a gas.
arrangement
liquid ……………………………………………….
gas …………………………………………………….
separation
liquid ……………………………………………….
gas ……………………………………………………
(ii) Compare the motion of molecules in a liquid to the motion of molecules in a gas.
motion
liquid ………………..
gas …………………….
(b) A sample of chlorine gas contains two isotopes, chlorine‑35 and chlorine‑37.
(i) Describe one similarity and one difference in the composition of a nucleus of chlorine‑35 and a nucleus of chlorine‑37.
similarity ……………………………………
difference …………………………………….
(ii) Another isotope of chlorine is chlorine‑36 which is unstable.
Fig. 6.2 shows how the number of undecayed nuclei in a sample changes over time
Use Fig. 6.2 to determine the half‑life of chlorine‑36.
half‑life = …………………………….. thousand years.
(iii) Chlorine‑36 decays to produce an isotope of argon.
Use the correct nuclide notation to complete the decay equation.
(c) The canister holds 0.020m3 of liquid chlorine when it is full.
When the canister is full of liquid chlorine, the total mass of the canister and the liquid chlorine is 13kg.
The density of liquid chlorine is 570kg/m3.
Calculate the mass of the canister when it is empty.
mass of empty canister = …………………………………………….. kg
▶️Answer/Explanation
Ans :
6(a)(i) (arrangement:) liquid; molecules are random / not regular and
(arrangement:) gas: molecules are random / not regular ;
(separation:) liquid molecules are touching and
(separation:) gas molecules are far apart ;
6(a)(ii) (motion:) liquid molecules can move around / flow over each other AND gas molecules are completely free to move ;
or
(motion:) liquid molecules movement is slower / gas molecules movement is faster ;
6(b)(i) (similarity:) number of protons ;
(difference:) number of neutrons/nucleons ;
6(b)(ii) 300 (thousand years) ;
6(b)(iii) \(_{17}^{36}\textrm{Cl}_{18}^{36}\textrm{Ar} + _{-1}^{0}\textrm{\ss } \) ;;
6(c) (mcl =) ρV OR 570 × 0.020 ;
(mcl =) 11.4 (kg) ;
(m = 13– 11.4 =) 1.6 (kg) ;
Question 7:-
(a) Fig. 7.1 is a diagram showing the difference in the cells lining the gas exchange system of a person that smokes tobacco and a person that does not smoke tobacco.
(i) Use the information in Fig. 7.1 to explain why tobacco smokers are more likely to get lung infections.
(ii) Identify the name of the cell labelled X in Fig. 7.1.
(b) Smoking causes cancer.
(i) State the names of two other diseases caused by smoking.
(ii) State the component of tobacco smoke that causes cancer.
(iii) Cancer is the result of a mutation in cells.
Define the term mutation.
(c) Alveoli are the gas exchange surface in humans.
Gases are exchanged by the process of diffusion.
Explain the advantage, in terms of diffusion, of the alveoli being thin and well ventilated.
thin …………………………………………………………………………………………………………………………..
well ventilated ……………………………………………………………………………………………………………
(d) State the names of two parts of the gas exchange system, that air passes through, between the mouth and the alveoli.
………………………. and ……………………………
▶️Answer/Explanation
Ans :
7(a)(i) cilia are shorter ;
unable to move (as much) mucus (which traps pathogens) ;
pathogens multiply / remain in the lungs / airway ;
7(a)(ii) goblet (cell) ;
7(b)(i) any two from:
COPD ;
coronary heart disease / CHD ;
AVP ;
7(b)(ii) tar ;
7(b)(iii) change in, gene / chromosome ;
7(c) thin – short(er) diffusion distance ;
well ventilated
– maintains a (steep) concentration gradient ;
7(d) any two from:
bronchi / bronchus ;
bronchiole ;
trachea ;
Question 8:-
(a) A student investigates the reactivity of four metals W, X, Y and Z.
They react the same sized piece of each metal with excess dilute hydrochloric acid.
Table 8.1 shows their observations.
Use the observations in Table 8.1 to list the metals in order of reactivity.
……………………………………………… most reactive
………………………………………………
……………………………………………… least reactive
(b) Fig. 8.1 shows the reactivity series of some metals.
The element carbon is also included in the list.
(i) Aluminium is extracted from the ore bauxite by electrolysis.
Use Fig. 8.1 to state and explain how copper is extracted from copper ore.
(ii) Calcium is more reactive than magnesium.
Suggest why.
(iii) Iron objects can be protected from rusting by coating them with zinc.
This is called sacrificial protection.
Use Fig. 8.1 to explain how sacrificial protection with zinc stops iron from rusting.
(c) Iron is more reactive than copper.
Iron metal reacts with aqueous copper chloride, CuCl 2.
Iron(II) chloride is made.
(i) Construct the balanced symbol equation for this reaction.
(ii) State the name of this type of reaction.
Choose from the list.
addition
displacement
neutralisation
thermal decomposition
(d) Aluminium is more reactive than iron but is more resistant to corrosion than iron.
Explain why.
▶️Answer/Explanation
Ans :
8(a) most reactive Z
X
W
least reactive Y ;;
8(b)(i) heat the ore with carbon ;
carbon is more reactive than copper or ORA /
carbon displaces the copper (from the copper ore) ;
8(b)(ii) idea that calcium atoms form positive (calcium) ions more easily (than magnesium) /
idea that calcium atoms lose electrons more easily (than magnesium) ;
8(b)(iii) zinc is more reactive than iron ;
zinc corrodes or oxidises / reacts with oxygen or loses electrons rather than iron ;
8(c)(i) Fe + CuCl2 → FeCl2 + Cu
formula of FeCl2 ;
equation ;
8(c)(ii) displacement ;
8(d) idea that aluminium forms an oxide layer (which adheres to the metal) ;
(oxide layer) prevents oxygen / water from reaching the aluminium / is impervious / impermeable (and prevents further
reaction) ;
Question 9:-
Fig. 9.1 shows a skydiver before the parachute opens.
(a) The skydiver has a mass of 84kg.
(i) State the name of the force labelled Q.
(ii) Calculate the size of the force labelled Q.
The gravitational field strength g = 10N/ kg.
force Q = …………….. N
(iii) The air resistance force at one point during the skydiver’s journey is 760N.
Use your answer to (a)(ii) to calculate the acceleration of the skydiver when the air resistance force is 760N.
acceleration = ………………………………………… m/s2
(b) Fig. 9.2 shows a speed–time graph for the skydiver’s journey.
The parachute is opened after 140s.
Explain, in terms of motion and forces, the shape of the speed–time graph after the parachute is opened.
from 140s to 180s ……………………………………………………………………………………………………..
after 180s …………………………………………………………………………………………………………………
(c) The skydiver falls from a height of 7500m.
Show that the loss in gravitational potential energy when the skydiver reaches the ground is 6.3MJ.
The gravitational field strength g = 10N/kg.
▶️Answer/Explanation
Ans :
9(a)(i) weight / gravitational force ;
9(a)(ii) (W= mg = 84 × 10 =) 840 N ;
9(a)(iii) (F =) 840 – 760 / 80 ;
(a =) F/m OR 80/84 ;
(a =) 0.95 (m/s2) ;
9(b) (140s to 180s) any two from ;
deceleration / slows down / negative acceleration ;
(deceleration is) non-constant ;
air resistance greater than weight / Q / upwards resultant force ;
(after 180 s) constant speed ;
no resultant force / air resistance = weight/Q ;
9(c) (GPE =) 84 × 10 × 7500 = 6 300 000 (J)/6.3 MJ ;
Question 10:-
(a) Fig. 10.1 is a diagram of part of the carbon cycle.
(i) State the name of process A in Fig. 10.1.
(ii) State the balanced chemical equation for process B in Fig. 10.1.
(iii) Draw an arrow on Fig. 10.1 to represent the process of feeding.
(iv) State the name of the cell structure where process C in Fig. 10.1 occurs.
(b) Tick (✓) all the boxes which show factors that cause an increase in carbon dioxide concentration in the atmosphere.
(c) Suggest two ways that deforestation causes extinction of animal species.
▶️Answer/Explanation
Ans :
10(a)(i) fossilisation ;
10(a)(ii) C6H12 O6 + 6O2 → 6CO2 + 6H2O ;;
10(a)(iii) arrow drawn from carbon compounds in plants to carbon compounds in animals ;
10(a)(iv) chloroplast ;
10(b)
10(c) any two from:
removal of animals, habitat / shelter / breeding grounds ;
removal of animals food source ;
AVP ;
Question 11:-
Electrolysis is the breakdown of an ionic compound by the passage of electricity.
(a) Complete the following sentences about the products of electrolysis.
Choose words from the list.
electrolytes
hydrogen
negative
neutral
non-metals
positive
During electrolysis of aqueous solutions, metals or ……….. are formed at the cathode. The anode is the ………… electrode where ………….. are formed.
(b) Aqueous copper(II) sulfate can be electrolysed using copper electrodes or using carbon (graphite) electrodes.
(i) State the product formed at the anode when aqueous copper(II) sulfate is electrolysed using each type of electrode.
copper electrodes ………………………………………………………………………………………………..
carbon (graphite) electrodes …………………………………………………………………………………
(ii) Fig. 11.1 shows the change in mass at the cathode when aqueous copper(II) sulfate is electrolysed using copper electrodes.
The investigation is done using different currents, each for the same length of time.
Predict the change in mass of the anode when the current is 0.25A.
change in mass of anode = ……………………. g
(iii) Construct the ionic half‐equation for the formation of the product at the cathode using carbon (graphite) electrodes.
▶️Answer/Explanation
Ans :
11(a) hydrogen ;
positive ;
non-metals ;
11(b)(i) copper electrodes – copper ions/Cu2+ ;
graphite electrodes– oxygen (gas) /O2 ;
11(b)(ii) –0.10 g / the mass decreases by 0.10 g ;
11(b)(iii) Cu2+ + 2e– → Cu ;;
Question 12:-
A student is investigating electrical circuits.
(a) Fig. 12.1 shows a circuit made by the student.
(i) The ammeter in Fig. 12.1 reads 0.50A.
The voltmeter in Fig. 12.1 reads 2.0V.
Calculate the resistance of the resistor labelled R in Fig. 12.1.
resistance = ……………………… Ω
(ii) The student notices that resistor R gets hot if the circuit is left connected for too long.
Describe, in terms of current, how the student prevents resistor R from overheating using the circuit shown in Fig. 12.1.
(b) The student replaces the 6.0V battery with a small solar cell.
The solar cell has an efficiency of 16%.
Calculate the power input to the solar cell when the solar cell provides 8.0W of power to the circuit.
power input = ……………….. W
▶️Answer/Explanation
Ans :
12(a)(i) (V=) 6.0 – 2.0 / 4.0 ;
(R =) V / I OR 4.0 / 0.50 ;
(R =) 8.0 (Ω) ;
12(a)(ii) increase the (total) resistance / decrease the current ;
by using the variable resistor ;
12(b) (power input =) power output / efficiency × 100 / 8.0 / 0.16 ;
(power input =) 50 (W) ;