# Homework Help: A Leak in a Bicycle Tire Problem

1. Dec 23, 2016

### BrainMan

1. The problem statement, all variables and given/known data

2. Relevant equations
pV = nRT

3. The attempt at a solution

I assumed that volume and temperature would stay constant. I assumed the volume wouldn't change because the volume of the tire doesn't change. This implies that

n1/p1 = n2/p2

n1p2 / p1 = n2

I found n1 by using the ideal gas law

pV/RT = n1 = 0.0592 moles of gas

Then I used the first equation to find n2 = 0.0431 moles.

Subtracting n1 - n2 I found that 0.0161 moles of gas escaped from the tire.

Converting the amount of moles lost to grams I get

0.0161 x 28 g N2/ 1 mol N2 = 0.451 g of N2 gas

The correct answer should be 1.8 g

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2. Dec 23, 2016

### Staff: Mentor

Show us how you got the initial mass of nitrogen.

3. Dec 23, 2016

### BrainMan

OK I see. I made an error in calculating the volume of the tire.

4. Dec 23, 2016

### Staff: Mentor

The ideal gas law uses absolute pressures, not gauge pressures.