1. Q1 a ∆ M = M M2
∆M = kg kg = kg
Q1b E = m L f
E = L f , ,000 J = 341,000 J/kg
∆M kg

2. Q2a ∆ M = M M2
∆M = kg kg = kg
E = m L v
E = L v J = 2,300,000 J/kg
∆M kg

3. Q3a. Heat transferred from water: E = m c θ = 0.12 x 4200 x (15-9)
= J
Q3b. Heat transferred to newly formed
water warming from 0C to 9 C: E = m c θ = x 4200x 9
= 302 J
Q3c. Energy to melt kg ice = J J = 2722J
Energy to melt 1 kg ice = J = 340,250 J/kg
0.008 kg

4. Q4 Energy required to vaporise 0.1kg water :E = m L f
E = 0.1 x 2.25 x106
E = 2.25 x105 J
Power (W) = energy transferred (J) or P = E=
time taken (s) t
so t = E P
= x105 J
3000 W
= s