Answer:
1100 J.
Step-by-step explanation:
- The boiling point of ethanol is 78 °C. So, the state of ethanol in the colloing temperature is gas.
c of ethanol (gas) is 2.0 J/g°C.
- The amount of heat added to a substance (Q) can be calculated from the relation:
Q = m.c.ΔT.
where, Q is the amount of heat released from ethanol cooling,
m is the mass of ethanol (m = 50.0 g),
c is the specific heat of ethanol in the gas phase (c = 2.0 J/g °C),
ΔT is the temperature difference (final T - initial T) (ΔT = 79.0 °C – 90.0 °C = - 11.0 °C).
∴ Q = m.c.ΔT = (50.0 g)(2.0 J/g °C)(- 11.0 °C) = - 1100 J.
The system releases 1100 J.