Answer: o.125 moles of gas X with a molar mass of 240
Explanation:
2.8 dm3 of gas X at STP has equal mass with 11.2 dm3 of C2H6 at STP. What is the number of mole if gas X has 30 grams?
the molar volume of any gas at STP is the volume of 1 mole at STP
and is 22.4 L
the C2H6 has a volume of 11.2L at STP so it has 0.5 moles
C2H6 has a molar mass of (2 X 12) +(6 X 1) = 24 + 6 = 30
0,5 moles weighs 15 gm at STP with
so 15 gm at STP with 2.8 L for gas X
PV=nRT
P=1 atm
T =273.2k
V =2.8
R =0.082
n = PV/RT = (1 X 2.8)/(0.082 X 273.2) =0.125 moles of gasX
the weight of gas X is 30 gms
so 30/.125 =240 g/mole = molar mass of gas X
