Page 181 - Chemistry

II. Maximum sports-award 1 ½ mks
Fail any one- award
III W√ ½ and Y√ ½
1
√
13. Sting of a bee is acidic and is neutralized by sodium hydrogen carbonate √ ½ into a salt,
carbon IV) oxide and water. This gives pain relief. √ ½
14. (a) There was production of effervescence . The lemon juice contain an acid that reacts with
the carbonate to produce carbon (IV) oxide.
(b) No production of bubbles. Copper is below hydrogen in the reactivity
15. (a) Yellow
Colourless
 ½

16. (i) K and M  1
(ii) K and M 

Air and combustion

1.
Oxygen

Water

2. a) 3 M g + N 2 g ________ M g 3 N 2 g
b) Argon
- It is inert

3. a) Rust is hydrated iron (III) Oxide
b) - Electroplating
- Painting
- Oiling
- Galvanization
c) - Salts
- Acids

3
8
4. a) Moles of copper / 64 = 0.125 moles of Mg / 24 = 0.125Mg reacts with both O2 and N2 gases in
the air while copper reacts with )2 only
There is greater change in the reaction with copper and smaller change in reaction with Mg

b) CUO (g) + H 2SO 4(q) ___________ CUSO 4(aq) + H 2O (l)
Balanced
Chemical symbols correct
State symbols correct

5. a) Dust particles
b) They readily solidify hence may block the pipes
c) Argon

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