Homework Help: Chemistry

Posted by Elizabeth on Friday, October 26, 2012 at 7:55pm.

I don't know exactly how to start this question:

A sample gas contains 2.95 x 10e24 molecules. The sample is 21.0% oxygen. Calculate volume of oxygen in liters assuming oxygen has a density of 1.308 g/L.

Please help me how to do this. I have been stuck and still trying to figure this one out.

Chemistry - bobpursley, Friday, October 26, 2012 at 9:13pm
figure moles of gas first; moles=2.95E24/avag number

then moles O2=molestotal*.21

then mass 02=molesO2*32grams/mole

then volume=massO2/density
Chemistry - Elizabeth, Friday, October 26, 2012 at 10:31pm
Okay. Please check. If you can please show me how its done when you put it together. I have it scattered so I was a bit stuck when I tried to do each step. I know dimensional analysis allows the cross cancelling when you do it on paper and its hard to see whats cancelled in each step on the computer. Thank you so much.

2.95E24/6.02E23=4.90 mol (g)

(4.90mol O)(0.21 O)=1.029 mol O

2(15.9994)=31.9988 g/mol O:

(1.029 mol O)(31.9988 g/mol)=32.9267652g

31.9988g/1.308L=24.46 L
Chemistry - DrBob222, Saturday, October 27, 2012 at 12:44am
Why don't you put it together on paper so you can see what cancels?

Answer this Question

Related Questions

Chemistry UPDATED QUESTION - A sample of air contains 78.08% nitrogen, 20.94% ...
Chemistry - A sample of air contains 78.8% nitrogen, 20.94% oxygen, 0.05% carbon...
Chemistry - consider 2 sample of nitrogen gas. sample 1 contains 1.5 mol of N2 ...
chemistry - A scientist collects a sample of carbon dioxide that contains 1.5 x ...
UNO - A blood sample contains several different types of cells, each of which ...
Chemistry - a sample of helium gas is in a closed system with a movable piston. ...
Chemistry - A sample weighing 3.064 g is a mixture of Fe2O3 (molar mass = 159.69...
Chemistry (Gas question) - The mean kinetic energy of the molecules in a sample ...
Chemistry - A rigid cylinder contains a sample of gas at STP. What is the ...
chem - A blood sample contains several different types of cells, each of which ...

For Further Reading

First Name:
School Subject:
Answer: