# Two Fairly Basic Thermodynamics Questions

## Homework Statement

How much ice must melt at 0 deg. C to gain 5 g of mass?

## Homework Equations

I cannot seem to find many equations that relate thermodynamics and mass, maybe that is my biggest problem... The only one i could find was
Q=Lm

## The Attempt at a Solution

I know the latent heat of fusion, but i do not know Q. I tried dividing both sides by L, giving me Q/L=m, but i wasn't sure where to go from there.

## Homework Statement

Calculate the entropy change in isotermal transformation of ideal gas at the temperature of 27.5 deg. C if work done by the gas is 3.5 J.

## Homework Equations

s(b)-s(a)=Cv*ln(Tb/Ta)+nR*ln(Vb/Va)
pV=nRT
dW=pdV

## The Attempt at a Solution

since Tb/Ta=1, Cv*ln(Tb/Ta) is reduced to zero, leaving us with
s(b)-s(a)=nR*ln(Vb/Va)
i then attempted to use the ideal gas law combined with dW=pdV but i found myself running in circles trying to figure out what to do with p and n and trying to find Vb and Va at the same time.