MARKING SCHEMES – CHAPTER 5 ( Air Around Us )
CHARACTERISTICS
QUES
1
a
b c d 2
3
a b c a b c d e
4
a b c d e f
5
a b c
6
a b
MARKS
P- N(78%) Q- O(21%) R- CO2 (0.03%) i. Neutral ii. Slightly soluble in water
3 2
i. Lime water turns milky/ cloudy ii. Gas R is carbon dioxide Q - Ignites Ignites a glowing splinter R - Lime water turns milky/ cloudy
1 1 2
V- 78% , W – O2 , X- inert gas, Y – 0.03% Water vapour , microorganism, microorganism, dust ( any 2) Lime water turns milky/ cloudy. R : Oxygen S : Carbon dioxide Green plants Tiger , elephant [ accept any suitable answer ] Respiration R - odourless, colourless, colourless, natural gas, supports supports Combustion S - odourless, colourless, colourless, acidic gas, does not not support combustion Not soluble, very soluble No change, Indicator change to orange Test splint ignites, Glowing splint extinguished Oxygen - Ignites glowing spliner Carbon dioxide dioxide - Lime water becomes becomes cloudy Nitrogen – Non-specific test Does not help burning,More dense than air, nonflammable To prepare ammonia,nitric acid Neon, Argon, Crypton ,Helium ,Xenon i. Used in filament bulb ii. Used in the weather forecast ballon i. J got continuous supply of oxygen ii. K Oxygen in K is more than L iii. L Oxygen in L is very low Oxygen is needed for combustion i. Lime water water turns cloudy ii. Charcoal(carbon) combines with oxygen to form carbon dioxide during combustion.
3 2 1
To investigate the effect of the size of a container on the length of time a candle burns Candle placed inside a bigger container will burnt longer than candle burn in a smaller container
1
TOTAL
9
6
2 1 2 1 2 2
10
6
3
1 1 2 2
15
3
1 1 1
6
1
1
c
6.2
8
2
b
To absorb carbon dioxide
1
c
Living things used oxygen during respiration.
1
c a
a
b
9.
3
i. The oxygen in M is more ii. The oxygen in N is less A candle placed inside a bigger container will burnt longer than a candle burn in a smaller container The candle will continue to burn i. The cockroach respires and uses O2, reduce the air pressure in the tube and causing the atmospheric pressure outside push the indicator inward ii. The germinating germinating seeds respires and uses O2, reduce the air pressure in the tube and causing the atmospheric pressure outside ,push the indicator inward iii. No change in air pressure inside the boiling tube
a b
7
i. Types of candle ii. Size of container iii.Length of time a candle burn
a
i.
carbon dioxide is released during combustion charcoal + oxygen carbon dioxide coal Change from blue to pink. The colourless liquid droplets is water Carbon dioxide + water
ii. iii. i. ii. iii. i. P : An acidic gas Q : A neutral gas
1
10 1
3
5
1 1 1 1 1 1
6
2 2
ii. P : carbon dioxide Q : oxygen b
10
i. ii. iii. i. ii. iii.
a
b
A: B: C:
30 s 20 s 10s
To absorb carbon dioxide There is no living things in boiling tube T Oxygen Size of beaker / volume of beaker beaker container Length of time the candle burns Size of candles
1 1 1
7
2 3
2
c
2 The len len th of time a candle candle burns burns 30 25
20
15
10
5
A
d
Time (s)
2
g
The bigger the size of the container, the longer the length of time candle burns.
1
a
(a)TV mechanical energy Boy singing sound energy Lightning bulb light energy Food chemical energy A stretched cord of a bow potential energy Top spinning kinetic energy Electrical energy heat energy + light energy A - fossil fuel C - Wind energy D - Hydroelectric Renewable energy source : Wind energy / hydroelectric energy
6
f
b 2
C
The bigger the size of the container, the longer the length of time candle burns. The size of container influenced the length of time candle to burns. 25s
e.
CHP 6 1
B
a
b
c
Non renewable energy source : Fossil fuel does not pollute the environment
1 1 12
1 7 3
2
1
6
3
3
a
P or R
1
b
potential energy
1
c
Potential energy
d 4
a b
c d 5
a
-/
Kinetic energy -/
-/
Potential energy
Kinetic energy
i. N ii. M/L iii. M/L iv. N the total energy is the same i. Light Light energy ii. Kinetic energy p = potential energy S= kinetic energy
d 6
a
1 chemical energy electric energy
2 6 2 3
1 3 2 P /S P / R R Q kinetic energy , potential energy
2 2 5
2
d
manipulated variable - oxygen responding variable - lime water turn cloudy water, gas carbon dioxide, energy
e
water, gas carbon dioxide, energy
2
a
P : sun energy Q : fossil fuel R : wind energy S: water energy T : animals and plants i. Group 1
c
b
5
1
i. lime water changes to cloudy ii. carbon dioxide is released when sugar is heated iii.carbon dioxide is released when sugar is heated burning sugar releases / produces energy
b
7
1
2
b
c
2
Renewable energy - P,R,S,T
9
1
2
4 Group 2 Non-renewable energy -Q
4
8
4
