Page 299 - Chemistry

(i) 3 consistent values average –
(ii) 2 consistent values averaged – (½ mk)
(iii) Otherwise award 0.
Penalties
(i) Answer should be at least 2 d.p. unless divided exactly.

b) No. of moles M 2 = ans(a) x 1 1
1000
Correct ans. 1

+
2-
c) 2H (aq) + CO 3 (aq) H 2O(l) + CO 2(g)

(i) Balancing = ½ mk
(ii) States (correct) = ½ mk

d) Moles of base = ½ x ans. (b) 1 mk
= correct answer 1 mk

e) Concentration = answer in (d) x 1000 1 mk
25

= Correct answer 1 mk

f) Mass of Na 2CO 3 = 106 x ans. (e) 1 mk

= Correct answer 1 mk
g) Mass of NaCl = 95 – ans. (f) (½)
% of NaCl = 95 – ans. (f) x 100
95
= Correct answer ½

2. a) TABLE 2
(i) Complete table 1 mk
(ii) Accuracy to S.V. 1 mk
(iii) Decimal 1 mk
(iv) Trend. 1 mk

b) Graph

Temp
Labeling – 1 mk
Plotting – 1 mk
Scale – 1 mk
Shape – 1 mk

Vol. of NaOH added

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