Questions on Gases
1. (a) (i) particles collide with/hit/bounce off (container) wall/eq; 1
(ii) An explanation to include:
1. greater volume/space/room;
2. fewer/less collisions (with container); 2
(b) (i) increases/eq; 1
(ii) increases/eq; 1
[5]
2. (a) (i) points plotted correctly;;
[Allow 1 mark for 4 correct]
straight line; 3
(ii) pressure increases with temperature; 1
(iii) line back tracked;
260 10 C; 2
(iv) absolute zero/ 0 K; 1
(b) An explanation to include:
• tyres get hot/increase in temperature;
• air expands/more collisions/air particles inside move more
/have more KE/OWTTE; 2
[9]
3. (a) An explanation to include:
1. moving gas particles;
2. hitting container walls;
[Allow bouncing off the sides for 2 marks]
[Ignore vibrating/collisions with other particles] 2
(b) increases;
increases;
stays the same;
stays the same; 4
(c) (i) increases;
in proportion/linearly/steady rate/OWTTE; 2
(ii) correctly indicated – intercept with horizontal axis; 1
(iii) zero/minimum; 1
[10]
4. (a) (i) An explanation to include:
• particles moving;
• collisions with walls/hitting walls;
• force produced;
plus 1 communication mark for ensuring that spelling,
punctuation and grammar are accurate, so that the meaning
is clear; 4
(ii) An explanation to include:
• more collisions;
• more particles present; 2
(b) (I) An explanation to include:
• not moving/all gases in solid state;
• no K.E.; 2
(ii) kelvin; 1
(iii) (+)373(K) 1
[10]
5. A calculation to show:
1/2. ;;
[1 mark for conversion to K and 1 mark for correct substitution]
3. P2 = 120 478 (Pa); 3
[Allow ;
P2 = 400 000 (Pa); 2 marks max]
[3]
6. (a) (i) An explanation to include two from:
1. molecules are moving / have (kinetic) energy;
2. colliding with container walls;
3. each collision produces a force; 2
plus one communication mark for using a suitable structure and
style of writing 1
(ii) An explanation to include:
1. molecules moving faster / more (kinetic) energy
/ moving more;
2. colliding more often with the walls / harder collisions
/ more force; 2
(b) (i) all points plotted correctly;; [Deduct 1 mark for every two errors]
straight line of best fit; 3
[Systematic error in vertical scale – max 2 marks]
(ii) straight line extended to pressure axis;
pressure of 104.5 ± 0.3 (kPa) / value from their graph; 2
[Bald, correct answer scores 2 marks]
(iii) molecules still have energy (to move) / molecules still moving; 1
(iv) –273°C / 0 K / absolute zero; 1
[12]
7. (a) (i) A description to include:
1. particles moving;
2. in all directions/randomly /
or implied by description (each other / walls); 2
[Arrows on diagram acceptable]
(ii) An explanation to include:
1. particles hit/collide with container walls;
2. producing a force; 2
(iii) pressure would increase/get bigger/larger; 1
(b) statements 2, 3 and 4 ticked ; ; ;
[If more than 3 ticked then deduct 1 mark for each error] 3
(c) An explanation to include two from:
1. temperature of air in tyre increases / hot / hotter;
2. particles hit more often/hit harder;
3. particles moving faster / more energy; 2
plus one communication mark for presenting relevant information in a
form that suits its purpose 1
[11]
8. (a) random;
collide;
force;
decreases;
decreases; 5
(b) (i) A description to include:
1. increases;
2. uniformly / equally / steadily / in a straight line /
positive correlation / OWTTE; 2
(ii) X on temperature axis between 250 and 300 K /
allow if on line in right place; 1
(iii) zero; 1
(iv) not moving; 1
[Reject mainly still]
[10]
