Question

1. how many grams of cl₂ are there in 5.25 grams fecl₃?

Explanation:

Step1: Find molar masses

$M_{FeCl_3}=55.85 + 3\times35.45=162.2$ g/mol, $M_{Cl_2}=2\times35.45 = 70.9$ g/mol

Step2: Calculate moles of $FeCl_3$

$n_{FeCl_3}=\frac{5.25}{162.2}\approx0.0324$ mol

Step3: Determine moles of $Cl_2$

From formula of $FeCl_3$, 1 mol $FeCl_3$ has 3/2 mol $Cl_2$. So $n_{Cl_2}=0.0324\times\frac{3}{2}=0.0486$ mol

Step4: Calculate mass of $Cl_2$

$m_{Cl_2}=0.0486\times70.9\approx3.45$ g

Answer:

3.45 g