Question #12566

1 Answer
Jan 4, 2018

#~~2.2xx10^21" molecules"#

Explanation:

At STP, a mole of a gas can occupy a volume of 22.4L. With this relationship, #etaNH_3# can be derived; i.e.,
#=80cancel(mLNH_3)xx(1cancel(LNH_3))/(1000cancel(mLNH_3))xx(1molNH_3)/(22.4cancel(LNH_3))#
#=0.003571molNH_3#

To find the number of molecules, #1molNH_3-=6.02xx10^24NH_3 " molecules"# is an important quantitative relationship to derive the unit desired in the problem; thus,
#=0.003571cancel(molNH_3)xx(6.02xx10^23"molecules " NH_3)/(1cancel(molNH_3))#
#=0.0215xx10^23" molecules "NH_3#
#~~2.2xx10^21" molecules "NH_3#