Heat, specific heat and Q = mcΔt
Answers are for parents and teachers.
1
Convert 100 K to °C and 20 °C to kelvin.
100 − 273 = −173 °C; 20 + 273 = 293 K.
2
Find the heat needed to warm 3 kg of water from 12 °C to 20 °C.
Δt = 8 K, Q = 3 × 4200 × 8 = 100 800 J.
3
A copper pan of mass 350 g is warmed by 60 K. Find Q (c = 390 J/kg·K).
m = 0.35 kg, Q = 0.35 × 390 × 60 = 8190 J.
4
Explain the sea breeze in three short steps.
Land warms faster; the air above it rises; cooler air from the sea flows in as a wind.
5
Why does a swimmer feel cold when leaving the water on a windy day?
Water on the skin evaporates quickly and takes latent heat from the body.