Question

How much heat is required to raise the temperature of 500 g of mercury from 20 °C to 100 °C? [Specific heat of mercury = 0.033 kcal/(kg °C)]

Answer 1

Data: m = 500 g = 0.5 kg,

T₁ = 20 °C,

T₂ = 100 °C, c = 0.033 kcal/(kg . °C), Q = ?

Q = mc (T₂ – T₁) 

= 0.5 kg × 0.033 kcal/(kg . °C) × (100 °C – 20 °C) 

= 0.5 × 0.033 × 80 kcal 

= 0.033 × 40 kcal 

∴ Q = 1.32 kcal 

Heat required = 1.32 kcal. 

[Note: 1kcal/(kg-°C) = 1 cal/(g.°C)]