# Calculate Mass of Nitrogen in 2.5 atm, 0.2 m3, 300C

• teggenspiller
In summary, the conversation discusses finding the mass of nitrogen in a container with given pressure, volume, and temperature. The equation PV/RT is used to find the number of moles, which is then multiplied by the molar mass of nitrogen to find the mass. However, the calculated mass does not match any of the options provided, leading to speculation about the given information or molar mass of nitrogen being incorrect.
teggenspiller

## Homework Statement

. A nitrogen in the container (molar mass is 28 g/mol) has a pressure of 2.5 atm, a volume of 0.2 m3, and a temperature of 300C. What is the mass of the nitrogen?

A. 125 g
B. 258 g
C. 421 g
D. 582 g
E. 864 g

## Homework Equations

I'll show you EXACTLY what i am doing:

## The Attempt at a Solution

so first i must find moles, since moles times molar mass = the mass. (is that correct??)

so n(moles)= PV/RT (

P=2.5 atm = 101325*2.5= 253312.5
V= .2 m^3
R= 0.0821 a constant
T= 300C = 573.15K

so 253312.5 * .2 / 0.0821 * 573.15 = moles

= 50662.5/ 47.1

=1075.63 = moles

the molar mass is 28g/mol
so 1075.63 * 28 grams=
30117.6

i have no idea what i am doing wrong, this whole class is finished today. i really need some help and an idea of what exactly i am doing wrong.

R is 8.314 J/mol/K, so your number of moles calculated is too large.

i was about to post that R= 8.315 J/mol.K , and the entire time (til just now) I've been using R= 8.315 J/mol.K ) but i thought id try soemthing else,
so with either R i haven't been able to come up with anything. i mea, if you solve it are you getting a correct answeR? is it working for you and maybe my calculations are off? or have i input something wrong. when i use R=8.315 J/mol.K i keep gettin 297 grams.

teggenspiller said:
i was about to post that R= 8.315 J/mol.K , and the entire time (til just now) I've been using R= 8.315 J/mol.K ) but i thought id try soemthing else,
so with either R i haven't been able to come up with anything. i mea, if you solve it are you getting a correct answeR? is it working for you and maybe my calculations are off? or have i input something wrong. when i use R=8.315 J/mol.K i keep gettin 297 grams.

I see 297.7 grams for the mass. Is that not correct? If it is not, then perhaps the pressure is gauge pressure and not absolute pressure? Did the problem specify?

oh yes perhaps. let me see...
so gauge pressure means 1atm+2.5 atm= 354637.5

*.2 = 70927.5
/ (8.31*573.15) = 14.89Do you think i should contact my teacher? perhaps maybe the solutionn isn't an option?

teggenspiller said:
oh yes perhaps. let me see...
so gauge pressure means 1atm+2.5 atm= 354637.5

*.2 = 70927.5
/ (8.31*573.15) = 14.89

Do you think i should contact my teacher? perhaps maybe the solutionn isn't an option?

Well, as I said, assuming that the given pressure is absolute pressure, I calculated about 298 grams for the mass.

I notice that the value for the volume is given to only one significant figure. Perhaps the answer needs to be specified with a corresponding accuracy: 300 grams.

or perhaps the molar mass of nitrogen is wrong? i searched google and see that 14.01g/mol is molarmass of nitrogen..

teggenspiller said:
or perhaps the molar mass of nitrogen is wrong? i searched google and see that 14.01g/mol is molarmass of nitrogen..

That's for monatimic Nitrogen, N. Nitrogen gas is N2, twice that.

bummer. I think i might just have to guess on this one.

298 g no matter how you try. Even assuming 3.5 atm (2.5 + 1) or 300 K (possible typo) neither of the answers given fits.

## What is the formula for calculating mass of nitrogen?

The formula for calculating mass of nitrogen is: mass = (pressure * volume) / (gas constant * temperature)

## What is the value of the gas constant?

The value of the gas constant is 0.0821 L*atm/mol*K.

## How do you convert 2.5 atm to Pa?

To convert from atm to Pa, you can use the conversion factor 1 atm = 101325 Pa. Therefore, 2.5 atm is equal to 2.5 * 101325 = 253312.5 Pa.

## What is the volume of 0.2 m3 in liters?

To convert from m3 to liters, you can use the conversion factor 1 m3 = 1000 L. Therefore, 0.2 m3 is equal to 0.2 * 1000 = 200 L.

## What is the mass of nitrogen in these conditions?

To calculate the mass of nitrogen, you will need to plug in the given values into the formula: mass = (2.5 atm * 0.2 m3) / (0.0821 L*atm/mol*K * 300 K) = 0.0204 moles. To convert moles to grams, you can use the molar mass of nitrogen, which is 28.0134 g/mol. Therefore, the mass of nitrogen is 0.0204 mol * 28.0134 g/mol = 0.5732 g.

• Introductory Physics Homework Help
Replies
13
Views
7K
• Introductory Physics Homework Help
Replies
8
Views
6K
• Introductory Physics Homework Help
Replies
6
Views
7K
• Introductory Physics Homework Help
Replies
7
Views
3K
• Biology and Chemistry Homework Help
Replies
4
Views
25K
Replies
5
Views
11K
• Biology and Chemistry Homework Help
Replies
7
Views
15K