Thursday

September 18, 2014

September 18, 2014

Posted by **Samuel** on Friday, October 15, 2010 at 4:55pm.

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

- Chemistry Help -
**DrBob222**, Friday, October 15, 2010 at 5:12pmWill 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 -
**Samuel**, Friday, October 15, 2010 at 5:48pmusing your method i got 0.45moles,is that correct?

- Chemistry Help -
**DrBob222**, Friday, October 15, 2010 at 6:06pmThat was my answer, also. Check my thinking on the problem.

- Chemistry Help -
**Amy**, Friday, October 15, 2010 at 6:11pmits saying that i am wrong, im stuck

- Chemistry Help -
**Amy**, Friday, October 15, 2010 at 6:37pmhello?

- Chemistry Help -
**DrBob222**, Friday, October 15, 2010 at 9:38pmAfter 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

**Answer this Question**

**Related Questions**

Chemistry - If it takes three "breaths" to blow up a balloon to 1.2 , and each ...

Chemistry - If it takes three "breaths" to blow up a balloon to 1.2 , and each ...

chemistry - hot-air balloon is filled with air at a volume of 3.64 x 10^3 m^3 at...

Physics - A person takes about 20 breaths per minute with 0.5 litre of air in ...

Chemistery - A hot air balloon with a volume of 3.20 x 10^3 L and 120 moles of ...

Chemistry - You have two gas-filled balloons, one containing He and the other ...

Chemistry - A balloon is floating around outside your window. The temperature ...

Physics - After rubbing a balloon against someone's hair, a balloon has ...

UNM - In an air-conditioned room at 19.0C , a spherical balloon had the diameter...

Chemistry-Please help - In an air-conditioned room at 19.0 degree celsius , a ...