Page 238 - Chemistry

c)Hydrogen sulphide or H 2Sg√1

26. i)this is the maximum mass of a salt that will dissolve in 100g of water at a given temperature √1
ii)15g dissolve in 25cm³ water
xg dissolve in (15x100)g√1
25
= 60g/100g√1
27. (a) Diagrammatical presentation on how to prepare an aqueous solution of hydrogen
chloride gas

HCl (g)
Inverted funnel

Trough

Water

(b) Ammonia gas *MAT

28. Mass of saturated soln. = 42.4 – 26.2 = 16.2
Mass of dry solid Y = 30.4 – 26.2 = 4.2g / 12.0
Solubility of Y = 4.2 x 100
12.0
35g per 100g of water
(b) – Used is fractional crystallization of salt mixture.

29. (a) 24 -19 = 5g of substance K will be produced
Reason: Solubility decreases with increase in temperature
1
(b) Gaseous state
30. Deep red solution will be formed. Equilibrium shifts to the right/forward reaction is favoured
3+
since Fe ions favours forward reaction.
 ½

31. a) They became a white powder
b) Efflorescency

32. a) calcium hydrogen carbonate/ magnesium hydrogen carbonate

b) Ca(LHCO 3) 2(aq) + Na 2CO 3(aq) ________ CaCO 3(g) + 2NaHCO 3(aq)

Mg(HCO 3) 2(aq) + Na 2CO 3(aq) ________ CaCO 3(g) + 2NaHCO 3(a)

c) Contains Ca2+ ions needed to harden teeth and bones

–
+
33. HCl g in water ionizes to produce H aq and Cl aq
+
HCl (g) in methylbenzene remain as moles hence no H ion

34. (i) Weak acid 1
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