Question #4b22d

1 Answer
Jan 15, 2018

Answer:

#4.9\times 10^{23}# oxygen atoms

Explanation:

The molar mass of #"AlPO"_4# is #26.98 + 30.97 + 4\cdot 16.00 = 121.95 \frac{\text{g}}{\text{mol}}#.

This comes from the periodic table.

Now, we convert #"25 g"# #"AlPO"_4# to moles #"AlPO"_4#:

#25\text{ g }\cdot\frac{\text{mol}}{121.95\text{ g}} = "0.205 mol AlPO"_4#

We can convert this to formula units of #"AlPO"_4# using Avogadro's constant, #6.02\times 10^{23}#.

#"0.205 moles" \cdot 6.02\times 10^{23}\text{ mol}^{-1} = 1.23\times 10^{23}# #"formula units AlPO"_4#

Since there are 4 oxygen atoms per formula unit of #"AlPO"_4#, we multiply this by 4 to get our answer:

#4\cdot 1.23\times 10^{23} = 4.9\times 10^{23}# oxygen atoms.