## Textbook Question 4A.1A

$w=-P\Delta V$
and
$w=-\int_{V_{1}}^{V_{2}}PdV=-nRTln\frac{V_{2}}{V_{1}}$

ramiro_romero
Posts: 90
Joined: Sat Sep 07, 2019 12:16 am

### Textbook Question 4A.1A

The Question states "Water expands when it freezes. How much work does 100. g of water do when it freezes at 0degreeC and pushes
back the metal wall of a pipe that exerts an opposing pressure of 1070 atm? The densities of water and ice at 0degreeC are 1.00 g/cm^3 and 0.92 g/cm^3, respectively."

I know this is a calculation of work for expansion, and I understand that external pressure is 1070 ATM. I get lost when it comes to understanding how to find delta V from the information given. If anybody can nudge me in the right direction i'd appreciate it!

Connie Chen 1E
Posts: 51
Joined: Mon Jun 17, 2019 7:24 am

### Re: Textbook Question 4A.1A

Using the densities, we can calculate the volume taken up by water. Since there are 100. g of water and the density is 1.00g/cm3, we can divide 100. g by 1.00g/cm3 to find that we have 100. cm3 water, which is equal to 100. mL. We can do the same for when it is ice. We still have 100. g, but this time, we divide by the density of ice, 0.92g/cm3 to get 108 cm3, or 108 mL. From there, we can find the change in volume by subtracting the initial volume from the final volume.