What fraction of the air molecules

[lalahelp]

Homework Statement

What fraction of the air molecules in a house must be pushed outside while the furnace raises the inside temperature from 17.0° C to 28.0° C? The pressure does not change since the house is not 100% airtight.

Homework Equations

v2/v1=17+273/28+273
=.963


Why is my answer wrong

 

[gneill]

You've calculated the fraction that's left inside rather than the fraction that was pushed outside.

 

[lalahelp]

is it .037?

 

[gneill]

is it .037?

Is that a guess or do you have a reason to back up that number?

 

[lalahelp]

its supposed to says 3.7 percent... I subtracted the 96.3 from 100

 

[gneill]

its supposed to says 3.7 percent... I subtracted the 96.3 from 100

Then that's okay. Looks good.

 

[lalahelp]

I put the answer but for some reason its still saying its incorrect?

 

[gneill]

I put the answer but for some reason its still saying its incorrect?

Is there a particular answer format that the question requires? Is it finicky about significant digits?

 

[lalahelp]

No and No... I am not sure why its doing this.

 

[gneill]

No and No... I am not sure why its doing this.

I don't know what else to suggest. I can't think of any other reasonable interpretation of 'fraction of the air molecules' that would lead to a different result.

 

[lalahelp]

yeh, Thank you for your help, I am going to email my proffessor about the question

 

[gneill]

Another Homework Helper* has suggested that it is perhaps possible that the question is looking for (n_28C-n_17C)/n_28C ("what fraction of the gas was pushed out") instead of (n_28C-n_17C)/n_17C ("what fraction of the gas will be pushed out"). It would make a small but noticeable difference in the result.


* Thanks D H!

 

[lalahelp]

Yes! that was correct Thank you D H!