Question

How much heat energy is given out by 270 g of a substance at 80°C if its temperature drops to 20°C?

[Specific heat capacity of the substance is 520 J kg⁻¹ K⁻¹]

Answer 1

Mass (m) = 270 g = 0.270 kg

Temperature, ΔT = 80°C − 20°C = 60 K

Specific heat capacity (c) = 520 J kg⁻¹ K⁻¹

Heat (Q) = mcΔT

= 0.270 × 520 × 60

= 8424 J

The heat energy given out by the substance is 8424 J (or 8.424 kJ).