pv=nrt question

At what temperature will 4.4g if carbon dioxide occupy a volume of 20dm3 at standard pressure.

My first question is how it possible to convert from dm3 and cm3 to m3?, Secondly can someone show me how to work it out :smile:

Reply 1

Jsuper

iirc there are 1000 cm3 in a dm3 and 1000000 cm3 in a m3. So to get from cm3 to m3, you divide by a million; to get from m3 to cm3 you times by a million; to get from cm3 to dm3 you divide by a thousand; to get from dm3 to cm3 you times by a thousand; to get from dm3 to m3 you divide by a thousand; and to get from m3 to dm3 you times by a thousand.

don't quote me on that though :smile:

as for the question, you have 100000 pascals of pressure (that's standard isn't it?), 0.1 moles of CO2 (4.4/44), 0.02 m3 volume (20/1000) and the constant is 8.31ish (or whatever you have been given).

so to find the temperature you'd do

T = pV/nR

and sub in the values.

Reply 2

Tes

Surely this is physics?

Anyway 1 m³ = 100dm³ = 1,000,000cm³

And 4.4g of CO₂ = 4.4 / (12 + 16x2) moles = 0.1moles

pV = nRT
p = 1atm = 100,000Pa
V = 0.02m³
n=0.1
R=8.31
T=?

therefore T = (100,000 x 0.02) / (0.1 x 8.31) = 2406 K

I think :P

Reply 3

jellytotz

basically... to convert cm3-->m3 you need to times the value by 10^-6
dm3-->m3 you need to times the value by 10^-3

so..in order to calculate the temperature..rearranging the equation gives you pv/nr = t

first you need to find the 'n' as thats not given to you..so you use the formula moles= mass/mr
4.4/ (12+32) {mr of carbon dioxide}
=0.1mol

now you just need to fill in the values:

(standard pressure is 100kpa so in Pa it's 100 000pa)
therefore,
[ 100 000 x (20 x 10^-3) ] / [ 0.1 x 8.31 ] = 2406.7K

which i think is right!
hope this helps!

Reply 4

Zoob

1 m3 = 1000 dm3; 1 dm3 = 1000cm3 :smile:

PV=nRT

hmm been a while since ive done this..see if i can help :redface:

Standard pressure is what? 1 pa? V=20dm^3
find how many moles there are in 4.4g of CO2 and you have n
R is a constant. rearrage to find T

T=PV / nR

that should get you answer :smile:

Reply 5

jellytotz

woo blakdog we got the same answerr! :biggrin: