Question

When 1 mole of ice melts at 0°C and at constant pressure of 1 atm. 1440 calories of heat are
absorbed by the system. The molar volumes of ice and water are 0.0196 and 0.0180 litre
respectively. Calculate AH and AE for the reaction.​

Answer 1

• ∆H and ∆E for the reaction is 1440 calories and 1439.96 calories.

Given-

• Moles of ice = 1
• Temperature = 0° C
• Pressure = 1 atm
• Heat absorbed by the system = 1440 calories
• Molar volume of ice = 0.0196 liter
• Molar volume of water = 0.0180 liter

Since heat is absorbed here at constant pressure so,

ΔH = 1440 calories

ΔE can be calculated by using the formula :ΔE = ΔH - PΔV

ΔV = 0.0196 L - 0.180 L = 0.0016 L

and pressure given is 1 atm

By putting the values we get -

ΔE = 1440 - 0.0016 × 24.217 cal (∵ 1 Latm =24.217 calories)

So, ΔE = 1439.96 calories

There is negligible work done here. So we can say that

ΔH ≈ ΔU

Regards