Determine the amount of energy that is required to lower the temperature of 15.6 g sample of gold from 58 ºC to 25 ºC.

Answer 1

Specific heat capacity of gold (Au) = 0.129 J / (g * C)

Recall that for any question involving a change in temperature, heat capacity and change in energy of a substance, we can use the formula (delta)H = mC(delta)T where (delta)T = final temp - initial temp (in celsius) and (delta)H is our change in enthalpy, or thermal energy

(delta)H = 15.6 g * (0.129 J /(g * C)) * (25 C- 58 C)

Note: when determining the change in temperature, it is not necessary to convert to Kelvin, as the change in temp in degrees Celsius is equal to the change in Kelvin

(delta)H = -66.4 Joules

Therefore, the system (gold) must lose 66.4 joules of energy to reach this new colder temperature