Z got wrong

Question 1

(b) (i) It took longer for the veins in the leaf to become red?

Answer 1

• water moved up through the stem
• through xylem vessels
• reference to transpiration
• description of transpiration
• veins contain xylem vessels

Question 2

define decomposition

Answer 2

small molecules being formed from larger ones;

Question 3

(iii) Explain why the temperature of the reacting mixture needs to be kept constant.

Answer 3

• temperature affects rate of reaction
• so control needed so rate investigation data is valid/ ref. to fair test
• additional collision theory detail related to rate

Question 4

(ii) State one property that is the same for all electromagnetic waves.

Answer 4

wave speed

Question 5

speed of wavelength

Answer 5

300 000 000 m/s

Question 6

describe the function of ciliated cell

Answer 6

cells secrete mucus ;
mucus traps pathogens ;
cilia push mucus containing pathogens
away from lungs / into throat ;

Question 7

whats in tobaco smokes that affect cilia/ciliated cell

Answer 7

smoke particles/tar

Question 8

how smoke particles/tar affect cilia, ciliated cell

Answer 8

1. cilia - paralysed/destroyed by (extra) mucus / mucus is not removed
2. ciliated - cell secrete more mucus

Question 9

Suggest why gasoline boils over a range of temperatures

Answer 9

gasoline is a mixture

gasoline all have different boiling points

Question 10

Explain, in terms of molecules and forces, why the properties of fuels are different ( diesel/gasoline)

Answer 10

molecules in gasoline are smaller
👉 attractive forces between molecules are lower
👉less energy needed to separate molecules

Question 11

State and explain how a covering of metallic zinc provides sacrificial protection of steel
from rusting

Answer 11

O2+H2O react with iron go form rust
👉 zinc provides barrier between iron and environment ;
👉zinc more reactive than iron
👉 zinc oxidises rather than iron

Question 12

suggest how bat detect water surface

Answer 12

reference to water having smooth surface
sound waves scattered in many direction from rough surface
bat receive more echoes form rough surface

Question 13

explain what is ment by a.c of frequency 50Hz

Answer 13

alternating current

changes 50 times per second

Question 14

describe the role of capillaries in vilus

Answer 14

absorb amino acids
absorb glucose
which dissolves in blood (plasma

Question 15

when light from air enter water

Answer 15

wavelength changes
speed changes
frequency remains

Question 16

values of resistance may not be reliable unless the
current is switched off between readings.
suggest why

Answer 16

(d) the wire heats up (and so change the resistance) ; [1]

Question 17

increases reliability

Answer 17

repeat ;

compare results / check consistency