DP Chemistry (last assessment 2024)
Question 17N.3.hl.TZ0.18c.i
| Date | November 2017 | Marks available | [Maximum mark: 2] | Reference code | 17N.3.hl.TZ0.18c.i |
| Level | hl | Paper | 3 | Time zone | TZ0 |
| Command term | Calculate | Question number | c.i | Adapted from | N/A |
c.i.
[Maximum mark: 2]
17N.3.hl.TZ0.18c.i
In the 20th Century, both fission and fusion were considered as sources of energy but fusion was economically and technically unattainable.
(c.i)
Calculate the loss in mass, in kg, and the energy released, in J, when 0.00100 mol of 228Ac decays, each atom losing an electron. Use section 2 of the data booklet and E = mc2.
228Ac → + 228Th
[2]
Markscheme
Loss in mass:
«(3.78532 x 10–25 kg – 9.109383 x 10–31 kg – 3.78528 x 10–25 kg) x 0.00100 x 6.02 x 1023 =»1.86 x 10–9 «kg»
Energy released:
«E = mc2 = 1.86 x 10–9 kg x (3.00 x 108 m s–1)2 =» 1.67 x 108 «J»