Question

When 15.0 g

of steam drops in temperture from 275.0°C
to 250° C, how much heat. energy is released?

Answer 1

Answer: The amount of heat needed to raise a substance's temperature by one Kelvin per kilogram. The heat needed to raise the temperature of a given substance with known mass can be calculated as follows:

ΔH=mCΔT

ΔH=Amount of heat energy supplied

m=Mass of the substance = 15 g

ΔT=Change in temperature = Tfinal−Tinitial = 250° C - 275.0°C = -25°C

C=Specific heat capacity = 2.02 J/g °C

ΔH=mCΔT

after putting the given values,

ΔH= -757.5 J

The formula also shows that heat energy is released (negative value) when the change in temperature is negative, i.e., when the temperature of a substance falls.