How much energy, in joules, is released when 17 kilograms of granite is cooled from 45 C to 21 C?
A. 365,575.3 J
B. 785,662.8 J
C. 901,980.3 J
D. 327,992.8 J
Answer is: D. 327,992.8 J. m(granite) = 17 kg = 17000g. ΔT(granite) = 21°C - 45°C = -24°C (-24K).
cp(granite)
= 0,804 J/g·°C, specific heat capacity of
granite.
Q = m(granite) · ΔT(granite) · cp(granite).
Q = 17000 g ·(-24°C)· 0,804 J/g·K.
Q = -327990 J. The granite lost 327990 joules of energy. Q - amount of energy gained or lost.
