F.2 Science有唔明;D

1) 點解有時要用Carbon dioxide黎滅火有時就用Water;?
2樣分別系要Remove d咩同埋點解;?

carbon dioxide can remove the supply of oxygen
water can be uesd to lower the temperature

因為water 導電,與電有關就唔好用water
之於幾時用Carbon dioxide幾時同Water 就自己衡量

1a) 當1個燈龍著火; 咁應該用咩整熄佢同點解;?
可以同carbon dioxide ,dry powder , sand, blanket
foam同water會整濕個lantern 可以會壞

1b)carbon dioxide ,dry powder , sand, blanket都得

2) The 'burning' of food to produce energy inside body cells is called _____. ?
食物點喺身體入面「Burning」?

.....is called respiration
food+oxygen-->carbon dioxide + water + energy
食物係係cell到燒燃產生energy
分別在於
burning :　vigorous and out of control
respiration:　slow and under control

3) 什麼是noble gas?

In form 2 level, u will learn 3
noble gases(means the gases which are unreactive,not
easy to react with other chemical)
Argon 氬, Neon 氖, Helium 氦

1. Carbon Dioxide > is to replace the oxygen which support burning.
Water > is to remove heat in the 'fire triangle' which can interrupt the burning process.
(Removing any significant facors of fire triangle would terminate the burning process)
To determine when you should use different types of fire extinguisher, you should read the label beside the body.

eg, paper lantern burnt, then you need to use a water one.
2. The burning of food to produce energy inside cells is called 'respiration'.
3. Gases which are inactive -
-not easy to take chemical reactions with other elements:
eg:
Helium (He), Neon, Argon (Ar)....

However, Hydrogen is a very active elements. It can easily take chemical reactions. According to what I know, as Hydrogen needs to have more atoms from other elements, thus it is an active element.

2) The 'burning' of food to produce energy inside body cells is called _____. ?
食物點喺身體入面「Burning」?


Respiration

food is breakdown into glucose and absorb by small intestine and glucose react with O2 in body cell to release energy.