Answer
a. 0.235 mole
b. 0.0244 mole
c. 0.0500 mole
Work Step by Step
a.
- Calculate or find the molar mass for $ NH_3 $:
$ NH_3 $ : ( 1.008 $\times$ 3 )+ ( 14.01 $\times$ 1 )= 17.03 g/mol
- Using the molar mass as a conversion factor, find the amount in moles:
$$ 4.00 \space g \times \frac{1 \space mole}{ 17.03 \space g} = 0.235 \space mole$$
b.
- Calculate or find the molar mass for $ Ca(NO_3)_2 $:
$ Ca(NO_3)_2 $ : ( 40.08 $\times$ 1 )+ ( 14.01 $\times$ 2 )+ ( 16.00 $\times$ 6 )= 164.10 g/mol
- Using the molar mass as a conversion factor, find the amount in moles:
$$ 4.00 \space g \times \frac{1 \space mole}{ 164.10 \space g} = 0.0244 \space mole$$
c.
- Calculate or find the molar mass for $ SO_3 $:
$ SO_3 $ : ( 16.00 $\times$ 3 )+ ( 32.07 $\times$ 1 )= 80.07 g/mol
- Using the molar mass as a conversion factor, find the amount in moles:
$$ 4.00 \space g \times \frac{1 \space mole}{ 80.07 \space g} = 0.0500 \space mole$$