Question

How much heat is necessary to convert `100g` ice at `0^(@)C` to water vapour `(` steam`)` at `100^(@)C` ? Given `DeltaH_(fusion)=80kcal//kg, DeltaH_(vap)=540kcal//kg,`heat capacity `=1.0 kcal//kg.`

Answer 1

`underset(0^(@)C)(Ice) underset(Fusion)overset(DeltaH_(1))rarrunderset(0^(@)C)(Water)overset(DeltaH_(2))rarr underset(100^(@)C)(Water)underset(V a p o risation) overset(DeltaH_(3))rarr underset(100^(@)C)(Steam)`
Thus, total heat needed for desired change
`=DeltaH_(1)+DeltaH_(2)+DeltaH_(3)`
`:. DeltaH_(Tot al)=0.1xx80+0.1xx1.0xx100+0.1xx540`
`=8.0+10.0+54.0=72.0kcal`