Question

How much heat is released when 50.0 g of ethanol cools from 90 °C to 79 °C?

Answer 1

Answer:

1100 J.

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.

Answer 2

Answer:

1100 J.

Explanation:

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