# Combined gas law

#### serendipityfox

Homework Statement
1.1L volume O2 collected in balloon, at 295K, 13.6 psi.
next day... 32C, 0.98 atm
what is the volume in the balloon.

a) 0.107L
b) 1.07L
c) 10.7L
d) 107.0L
Homework Equations
pv/t = pv/t
1atm = 14.7psi
P1= 13.6 V1= 1.1 T1= 22 P2 = 14.4 V2= x T2 = 32

am i missing something?

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#### BvU

Homework Helper
Yes, an explanation what the numbers represent. Hint: 22 is NOT T1 in your relevant equation.

#### serendipityfox

Damn! I need to convert to Kelvin for gas problems, right

#### gmax137

"13.6 psi" in the problem statement is ambiguous. Is that psia or psig? Doubly confusing since a "balloon" suggests pressure higher than ambient. You can work out the answer both ways and then see whether the available choices allow you to eliminate one possibility. I call that a crummy question.

#### Chestermiller

Mentor
Does increasing the pressure cause the volume to decrease or increase?

Does decreasing the temperature cause the volume to decrease or increase?

#### Chestermiller

Mentor
I get none of the answers that are given.

#### gmax137

I got (b) 1.07 liter by assuming the 13.6 psi initial condition is psia. Also note, the initial volume is 1.1 liters; I missed that the first time thru (thinking it was 1 liters).

#### Chestermiller

Mentor
I got (b) 1.07 liter by assuming the 13.6 psi initial condition is psia. Also note, the initial volume is 1.1 liters; I missed that the first time thru (thinking it was 1 liters).
I also got 1.07 now. Initially I used 293 instead of 305 for some reason.

Last edited:

#### serendipityfox

thanks for the answers, i am happy with what i have... i am now sure the question is designed to dilineate two levels of students, and so there's no need for me to progress further for now.

"Combined gas law"

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