How do you calculate the density of butane,(C4H10) at STP??

1 Answer
Apr 12, 2018

#2.59xx10^-3"g cm"^-3# or #2.59"kg m"^-3#

#"density"="mass"/"volume"# so let's find a mass and a volume!

Explanation:

We will use the fact that, at STP (#0^@C# and 1atm), 1 mole of an ideal gas occupies #22.4"dm"^3#

This means 1 mole of butane has a volume of #22.4"dm"^3# at STP.

#:.v=22.4"dm"^3#
#=22.4xx10^3"cm"^3#
#=22.4xx10^-3m^3#

1 mole of butane has the same mass in grams as its relative molecular mass.

#M_r=4xx12+10xx1#
#=58#

#:. m=58g=58xx10^-3kg#

Using #rho=m/v# where #rho# is density:

#rho=58/22.4xx10^3#
#=2.59xx10^-3"g cm"^-3# or #2.59"kg m"^-3#