Page 288 - Chemistry

(b) NaOH (aq) + HCl (aq) NaCl (aq) + H 2O (l)
Mole ratio 1 :1
0.5M 0.5M
25 x 0.5 = 0.0125 moles
1000

(c) Mole ratio
NaOH : HCl = 1 :1
Molarity of NaOH is 0.5M

Table II
Marking should be done as in table 1.
Calculations
(a) ) Titre 1 + Titre II + Titre III = Answer
3

(b) 1000 = 0.5moles
3
100cm = ?
100 x 5 = 0.05moles
1000
3
100cm = 0.05moles
3
25cm = ?
25 x 0.05
100
= 0.0125moles
(c) mole ration 1:2
Moles of carbonate = ½ x 0.0125 = 0.00625moles
(d) 125

Question 2
Table III
Marks should be distributed as follows :
(i) Complete table
- Incomplete table with more than 5value ½mk
(ii) Decimal
o Accept whole numbers for time
1
- / t must be decimals not fractions
(iii) Trend in time
- Accept reducing values for time
1
(iv) Trend in / t
(b) The value given must shown on the graph
o
- Conversion of 318K to C is very important before reading form the graph.
GRAPH
- Labeleling ½ mk for both axes
- Scale ½ k (at least ¾ pg)
- Plotting 1mk
- Shape 1mk (should be a curve)

Rate of
reaction / t
1

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o
Temp C