By law of conservation of energy, the amount of heat lost
by the metal should be equal to the amount of heat gained by water. That is,
the change in energy (expressed in enthalpies) should be equal:
- (ΔH)metal = (ΔH)water
Take note of the negative sign in front of (ΔH)metal, this
means that heat is lost by this metal.
Where ΔH or change in enthalpy is:
ΔH = m Cp (T2 – T1)
So,
- 15 g (Cp) (23 °C – 99 °C) = 75 g (4.18 J/g * °C) (26 °C –
23 °C)
1,140 Cp = 940.5
<span>Cp = 0.825 J/g * °C (ANSWER)</span>
The answer is gonna be D I believe
The doubling the amount will change the gibbs free energy as it is an extensive property which depends upon the the amount of the substance
However as asked in question the DeltaG has unit of kcal /mol
So we have already defined the amount of substance to be one mole this means the value per mole will be same irrespective of the amount taken as we are reporting it for a fixed one mole of a substance
Hence answer is
-100 kcal/mol
