Calculating Initial Pressures in Rigid and Piston Containers with Monatomic Gas

[skinard360]

Two 800\; cm^3 containers hold identical amounts of a monatomic gas at 20^\circ C. Container A is rigid. Container B has a 100\; cm^2 piston with a mass of 10 kg that can slide up and down vertically without friction. Both containers are placed on identical heaters and heated for equal amounts of time.
What are the initial pressures in containers A and B?

I assumed that the net force was zero and used the equation
pressureB = [(weight of piston)/(area of piston)]+101,300

and I assumed that the pressure of the first piston was 101,300 Pa

but this was wrong, I'm not sure what else to do??

 

[lalbatros]

Have you checked the units for (weight of piston) ?
Show us your calculation.

 

[skinard360]

p = (w/A) + p(atmosphere)

p = (98/.01) + 101,300

the answer is in Pascals

 

[skinard360]

ok...I got the answer...thanks :)