Analytical Chemistry

(Chris Devlin) #1

Chapter 10


(2) Note: Tritium is a diatomic molecule.


Initial activity 9.6 × 1010 Bq, 2.59 Ci

After 2.5 years 8.3 × 1010 Bq, 2.25 Ci

(3) Half-lives: 0.8 h, 8.1 h


Initial activities: 7300 counts min-^1 ; 520 counts, min-^1

(4) 1.10 × 105 Bq


(5) 4.04 × 106 Bq


(6) 21.4 mg


(7) 100 pmol


Chapter 11


(1) The decomposition of copper (II) sulphate when heated to 400°C is seen to occur in three stages.
Since the weight scale shows that 0.5 mg (50%) corresponds to 40 mm, then 1 mm = 1.25%


(a) Up to ≈ 100 °C, 11.5 mm ≈ 14.4%.

Calculated loss 14.4%

(b) From approximately 100°C to 200°C a further drop of 11.5 mm gives a further loss of 14.4%, to
a total loss of 28.8%.

Calculated loss 14.4%

(c) From approximately 200°C to 400°C a further drop of about 6 mm gives a further loss of about
7.5%, to a total loss of 36%.

Calculated loss 7.2%
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