Question

You find a 1979 copper penny (and note that pre-1982 pennies are pure copper) in the snow and pick it up. How much heat does the penny absorb as it warms from the temperature of the snow, −5.0∘C to the temperature of your body, 37∘C? Assume the penny is pure copper and has a mass of 3.10 g. (The specific heat capacity of copper is 0.385 J/(g⋅∘C).)

Answer 1

The penny absorbs 50 J.

q = mcΔT

ΔT = T_f – T_i = 37 °C – (-5.0 °C) = 42 °C

q = 3.10 g × 0.385 J·°C⁻¹g⁻¹ × 42 °C = 50 J

Note: The answer can have only two significant figures because that is all you gave for the temperature of your body.