Please Help?

Question

The pressure of O2 in a 15.0 L flask is 0.581 atm at 52 °C. What mass of O2 is in the flask?

a.0.839 g

b.8.15 g

c.10.5 g

d.33.9 g

I think it is A

Answer 1

PV = nRT

n = number of moles

R = gas constant = 0.08206 (atm∙L)/(mol∙K)

T = temperature in kelvins

P = absolute pressure in atm

V = volume in liters

"pressure of O2 in a 15.0 L flask is 0.581 atm at 52 °C"

n = PV/RT = (0.581)(15) / (0.08206)(273.15+52) = 0.327 moles

O₂ has a molecular weight of 2•16 g/mol

0.327 moles x 32 g/mol = 10.45 g (c)