A 630. mL flask contains O2 at a pressure of 0.75 atm and a temperature of 20°C. What mass of O2 is present?
I know you Use PV = nRT and solve for n = number of mols gas. Then n = grams/molar mass and solve for grams.
630 ml= 1l= 1000ml
0.63 L
20=293.15 k
0.75*0.63=n*0.0821*293.15
=1687.13002
I get the wrong answer don't know what I'm doing wrong
Your problem here is that you have have calculated n wrong and I pointed that out to you in an earlier response. You must be hitting th wrong keys on your calculator. You should be getting approx 0.02.
The problem asks for grams and you quit too early.
n = grams/molar mass
approx 0.02 = g/32
so about 0.02 x 32 = about about 0.64. Surely you didn't read my post. I did this about 5 hours ago for you.