A 5.00 liter sample of gas measured at 27.0?C and 1.25 atm of pressure has a mass of 10.13 g. What is the mole

Question

a)39.9

b)0.898

c)2.57

d)2.50 x 10

Answer 1

I assume that you want to know the molecular mass of the gas.

PV = nRT

126.625 * 5 = n * 8.31*300

n = 126.625*5/8.31*300

n = 0.254 moles

Mass is 10.13, therefore molar mass = 10.13/0.254 = 39.9

Answer is a) above.

Answer 2

Assuming this is an ideal gas, you can use the equation

PV = nRT

where P = pressure ( atm )

V = vol ( L )

T = temperature ( ºK ) , R = universal gas constant = 0.08205

n= no of moles

therefore solving for n ,

n = PV / RT

n = ( 1.25 ) ( 5 ) / ( 0.08205 ) ( 27 + 273 )

n = 0.25 moles