How many moles of #CO_2# (g) are in a 5.6 L sample of #CO_2# measured at STP?

1 Answer
Jan 30, 2016

Answer:

#"moles"=0.25#

Explanation:

Using the ideal gas equation, we can solve for the number of moles:

#PV=nRT#

where:
#P=#pressure
#V=#volume
#n=#moles
#R=#universal constant #(8.314(kPa*L)/(mol*K))#
#T=#temperature (Kelvin)

Recall that at STP conditions:

#P=101.325# #kPa#
#T=273.15# #K#

To solve for the number of moles of carbon dioxide gas, substitute your known values into the ideal gas equation:

#PV=nRT#

#n=(PV)/(RT)#

#n=((101.325kPa)(5.6L))/((8.314(kPa*L)/(mol*K))(273.15K))#

#n=((101.325color(red)cancelcolor(black)(kPa))(5.6color(orange)cancelcolor(black)(L)))/((8.314(color(red)cancelcolor(black)(kPa)*color(orange)cancelcolor(black)(L))/(mol*color(green)cancelcolor(black)(K)))(273.15color(green)cancelcolor(black)(K)))#

#n=0.2498580892# #mol#

#n=0.25# #mol# (rounded to #2# significant figures)

#:.#, there are #0.25# #mol# in #5.6# #L# of #CO_(2(g))# at STP conditions.