Work done to melt ice then vaporize it

[chemman218]

1. Homework Statement

When a lab associate melts 10.9 g of ice at 0 °C, then heats the liquid to its boiling point and then vaporizes it against 1.0 atm of pressure, find the work done in kJ.

Homework Equations

work = -Pext(deltaV)

The Attempt at a Solution

I found that delta H = 32.836 kJ, but delta h does not equal work. I know that the work, should be the expansion of water from liquid to gas
against 1 atm of pressure then i need to convert that value in L-atm to Joules.

I just am not sure how to go about getting the change in volume since it is not an ideal gas situation. Or is it?

 

[anathema]

[/b]

Hello,

Thank you for your question! The work done in this scenario can be calculated using the formula W = -Pext(deltaV), as you mentioned. However, there are a few additional steps that need to be taken to find the change in volume and convert it to Joules.

First, let's start by finding the change in volume of the water from liquid to gas. To do this, we can use the ideal gas law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature. Since we are given the pressure and temperature, we can solve for the number of moles (n) using the mass of water and its molar mass.

Next, we can use the molar volume of an ideal gas (22.4 L/mol at STP) to find the volume of the water in its gaseous state. This will give us the change in volume (deltaV) that we need to plug into the formula.

Once we have the change in volume, we can convert it to Joules using the conversion factor 1 L-atm = 101.3 J. This will give us the work done in Joules. To convert to kJ, simply divide by 1000.

I hope this helps! Let me know if you have any further questions or if you need clarification on any of the steps. Good luck with your calculations!