chemistry
posted by ellie .
A 0.286g sample of carbon dioxide, CO2, has a volume of 585mL and a pressure of 495mmHg . What is the temperature, in kelvins and degrees Celsius, of the gas?

Use PV = nRT.
P = 495 mm; convert to atm.
V = 585 mL; convert to L.
n = g/molar mass = 0.286/44 = ?
R = you know
T = kelvin. Substitute and solve for T in kelvin, the
K = 273 + C to calculate C. 
When I've done the equation I've gotten 713.971 K for the first part. What have I done wrong?

Probably nothing. Using 44 for the molar mass of CO2 I obtained 714.3 K. You may have punched in a wrong digit somewhere.
For n I have 0.286/44 = 0.00650
Using 44.01 for the molar mass gave me 714.5 K. 
thanks for your help