# Chemistry Help

posted by .

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

• Chemistry Help -

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

• Chemistry Help -

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

• Chemistry Help -

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

• Chemistry Help -

its saying that i am wrong, im stuck

• Chemistry Help -

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

## Similar Questions

1. ### chemistry

hot-air balloon is filled with air at a volume of 3.64 x 10^3 m^3 at 745 torr at 39C. the air in balloon is heated to 60C, causing balloon to expand to a volume of 4.50x 10^3 m^3. what is the ratio of the number of moles of the air …
2. ### Chemistry

If it takes three "breaths" to blow up a balloon to 1.2 , and each breath supplies the balloon with 0.060 moles of exhaled air, how many moles of air are in a 3.0 balloon. Express your answer in moles using two significant figures …
3. ### Chemistry

If it takes three "breaths" to blow up a balloon to 1.2 , and each breath supplies the balloon with 0.060 moles of exhaled air, how many moles of air are in a 3.0 balloon. Express your answer in moles using two significant figures …
4. ### Physics

A person takes about 20 breaths per minute with 0.5 litre of air in each breath. How much heat is removed per hour by the moisture in the exhaled breath if the incoming air is dry and the exhaled breath is fully saturated?
5. ### Physics

After rubbing a balloon against someone's hair, a balloon has accumulated a static electric charge. The air inside the balloon has the same density as the air outside of the balloon, and the balloon itself weighs 1.41mN. How many free …
6. ### Physics

A hot-air balloon is accelerating upward under the influence of two forces, its weight and the buoyant force. For simplicity, consider the weight to be only that of the hot air within the balloon, thus ignoring the balloon fabric and …
7. ### Chemistery

A hot air balloon with a volume of 3.20 x 10^3 L and 120 moles of air is at a temperature of 20C. How many moles of air will the balloon contain if it expands to 4.80 x 10^3 L and the air is heated to 45C?
8. ### chem

A hot air balloon with a volume of 3.20 x 103 L and 120 moles of air is at a temperature of 25 °C. The air is heated to 65°C and 250 moles of air is added. What will the new volume of the balloon be?
9. ### Chemistry

A hot air balloon is filled with hot air and the hot air forces the volume of the balloon to expand until the density of the gas in the balloon is less than the density of the outside air. The volume must be 20% larger than the balloon …
10. ### chemistry

A hot air balloon is filled with hot air and the hot air forces the volume of the balloon to expand until the density of the gas in the balloon is less than the density of the outside air. The volume must be 20% larger than the balloon …

More Similar Questions