Page 300 - Chemistry

c) (i) - Shown in graph (½ mk)
- Correct reading (½ mk)
(ii) ∆T shown in graph - (½ mk )
Correct answer from graph - (½ mk)

d) ∆H = MC∆T = (23 + c(i) x 4.2 x c (ii) 1 mk
Correct answer

e) Moles = 1 x 23 ½ = 0.023 moles  ½
1000

f) Molar heat = 1 x ans. (d) 1
ans. (e)
= Correct answer. 1
Observation Inferences
2+
3+
a) Colourless solution forms Soluble salt/ Absence of coloured ions /Fe , Fe , Cu 2+
1 absent 1
2+
2+
3+
2+
b) White ppt 1 soluble 1 Ba , Pb , Zn , or Al present.1
in excess
2+
3
2+
c) White ppt. insoluble in Ba , Pb , or Al present. 1
excess. 1
2-
d) No white ppt. // no ppt. SO 4 absent. 1
1

CALCULATIONS

b. (i) Moles of soltn P = average titre x 0.2 ½ mk
1000

= correct Ans. ½mk
b. (ii) NaOH (aq) + HCL (aq) Nacl (aq) + H2O (l)
Mole ratio= NaOH: HCl is 1:1 

Moles of NaOH soln S = 1 x Ans. b(i) ½mk
1
= corr. Ans.

3
b. (iii) 25cm soltn. S = Moles in Ans. b(ii)
3
100cm soltn. S = ?
= 100 x Ans. b(ii) ½mk
25 
=Correct Ans. ½mk

(c) 100cm 3 soltn S Moles in Ans. b(iii) 

3
200cm Soltn S 200 x moles in Ans. b(iii) ½mk
100
3
moles in 25cm NaOH = 200 x moles in Ans. b.(iii) ½mk
100 
= 2 x moles n Ans. b(iii)
= Correct Ans.  ½mk
3
(f) Moles of R in 25cm = Ans. (e)
Moles of R in 1000 = ?
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