Question #bb58b

1 Answer
May 22, 2016

Answer:

#1.32\times10^{22}" formula units of CaO"#. Note that #"CaO"-does not form discrete molecules so we talk in terms of formula units. Unfortunately the question itself misleads by using "molecules".

Explanation:

First you need the molar mass. #"CaO"# has one atom of #"Ca (atomic mass 40.08)"# and one atom of #"O (atomic mass 16.00)"#. So we add the two atoms:

#40.08+16.00=56.08" g/mol"#

Now divide the mass by the molar mass and multiply by Avogrado's Number:

#{1.23" g"}/{{56.08" g"}/"mol"}\times{6.022\times10^{23}" formula units"}/"mol"#
#=1.32\times10^{22}" formula units"#