Answer
Theoretical yield = 8.55 g
Percent yield = 76.6%
Work Step by Step
1. Calculate or find the molar mass for $ S_8 $:
$ S_8 $ : ( 32.07 $\times$ 8 )= 256.56 g/mol
2. Using the molar mass as a conversion factor, find the amount in moles:
$$ 4.06 \space g \times \frac{1 \space mole}{ 256.56 \space g} = 0.01583 \space mole$$
3. Calculate or find the molar mass for $ Cl_2 $:
$ Cl_2 $ : ( 35.45 $\times$ 2 )= 70.90 g/mol
4. Using the molar mass as a conversion factor, find the amount in moles:
$$ 6.24 \space g \times \frac{1 \space mole}{ 70.90 \space g} = 0.0880 \space mole$$
5. Find the amount of product if each reactant is completely consumed.
$$ 0.01583 \space mole \space S_8 \times \frac{ 4 \space moles \ S_2Cl_2 }{ 1 \space mole \space S_8 } = 0.0633 \space mole \space S_2Cl_2 $$
$$ 0.0880 \space mole \space Cl_2 \times \frac{ 4 \space moles \ S_2Cl_2 }{ 4 \space moles \space Cl_2 } = 0.0880 \space mole \space S_2Cl_2 $$
6. Since the reaction of $ S_8 $ produces less $ S_2Cl_2 $ for these quantities, it is the limiting reactant.
7. Calculate or find the molar mass for $ S_2Cl_2 $:
$ S_2Cl_2 $ : ( 35.45 $\times$ 2 )+ ( 32.07 $\times$ 2 )= 135.04 g/mol
8. Using the molar mass as a conversion factor, find the mass in g:
$$ 0.0633 \space mole \times \frac{ 135.04 \space g}{1 \space mole} = 8.55 \space g$$
9. Calculate the percent yield:
$$percent \space yield = \frac{actual \space yield}{theoretical \space yield} \times 100\%$$
$$percent \space yield = \frac{6.55 \space g}{8.55 \space g} \times 100\% = 76.6\%$$
