If it takes three "breaths" to blow up a balloon to 1.2 L, and each breath supplies the balloon with 0.060 moles of exhaled air, how many moles of air are in a 3.0 L balloon?

i am trying to use v1/n1=v2/n2 but i am stuck, can u help? thank you

After re-reading the problem very carefully, I'm sticking with my answer. By the way, your v1/n1 = v2/n2 is exactly the same.

1.2/0.18 = 3.0/n2
n2 = 3.0 x (0.18/1.2) = 0.45
I think the problem with your answer is that the number 0.06 moles has only one significant figures in it; therefore, the answer must be rounded to one s.f. So the answer must be rounded from 0.45 moles to either 0.4 or 0.5 depending upon how your teacher has told you to round number when they end in 5. The rule I follow is to "round to the even number"; therefore, I would round to 0.4 but not everyone follows that rule. Let me know if this does or does not take care of the problem. As an interesting aside, note that if we round at the end, I would round to 0.4 BUT if I rounded at the 7.5 mark, I would round that to 8 and 8 x 0.06 = 0.48 which of course rounds to 0.5

Will something like this work?

# breaths to blow 3.0 L balloon = 3 breaths x (3.0 L/1.2 L) = 7.5 breaths [or you can use the dimensional analysis method which will be 3.0
L x (3 breaths/1.2 L) =7.5 breaths.
Each breath has 0.06 moles; therefore,
0.060 moles/breath x 7.5 breaths = ?? moles

using your method i got 0.45moles,is that correct?

That was my answer, also. Check my thinking on the problem.

its saying that i am wrong, im stuck

Of course, I can help you!

To solve this problem, you can indeed use the ideal gas law equation V1/n1 = V2/n2, where V represents the volume, and n represents the number of moles of gas.

Let's break down the steps to find the number of moles of air in a 3.0 L balloon.

Step 1: Calculate the moles of air from the given information.
Based on the information provided, we know that it takes three "breaths" to fill a balloon to 1.2 L, and each breath supplies the balloon with 0.060 moles of exhaled air.

So, the moles of air in 1.2 L of the balloon can be calculated as follows:
n1 = 0.060 moles/breath * 3 breaths = 0.180 moles of air

Step 2: Solve for the number of moles of air in a 3.0 L balloon.
Now, we need to find the number of moles in a 3.0 L balloon using the obtained value from step 1.

Using the ideal gas law equation V1/n1 = V2/n2, we can rearrange the equation to solve for n2 (which is the number of moles in the 3.0 L balloon).

V1/n1 = V2/n2
(1.2 L)/(0.180 moles) = (3.0 L)/(n2)

Now, cross multiply to isolate n2:
(1.2 L) * (n2) = (0.180 moles) * (3.0 L)
1.2n2 = 0.54 moles

Finally, we solve for n2 by dividing both sides of the equation by 1.2:
n2 = 0.54 moles / 1.2
n2 ≈ 0.45 moles

Therefore, there are approximately 0.45 moles of air in a 3.0 L balloon.