Question

a 45g sample of water at 12°c is heated with 15kJ of energy. What will be the final temperature of the water?

Answer 1

Answer:

Final temperature  = 91.75  °C

Explanation:

Given data:

Mass of water = 45 g

Initial temperature = 12 °C

Energy required = 15 Kj (15000 j)

Final  temperature = ?

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Solution:

Q = m.c. ΔT

15000 j = 45 g × 4.18 j/g.°C × (T2 -T1)

15000 j = 45 g × 4.18 j/g.°C × (T2-  12 °C)

15000 j = 188.1 J/°C × (T2-  12 °C)

15000 j / 188.1 J/°C = T2-  12 °C

79.745 °C  = T2 - 12 °C

T2 = 79.745 °C +  12 °C

T2 = 91.75  °C