Question

Law of Conservation of Mass Assigned as Homework HQ4.01 In the following chemical reaction between H2 and Cla to produce HCl, what is the sum of the mass of HCl produced plus the mass of left over reactants when 3.36E-1 g of H2 completely reacts with 1.245E+1 g of Cl2? H2(g) + Cl2 (g) → 2HCl(g) T Respond with the correct number of significant figures in scientific notation

Answer 1

Answer: The mass of left chlorine gas is 0.497 grams and HCl is 6.13 grams

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$     .....(1)

• For hydrogen gas:

Given mass of hydrogen gas = $3.36\times 10^{-1}=0.336g$

Molar mass of hydrogen gas = 2 g/mol

Putting values in equation 1, we get:

$\text{Moles of hydrogen gas}=\frac{0.336g}{2g/mol}=0.168mol$

• For chlorine gas:

Given mass of chlorine gas = $1.245\times 10^1=12.45g$

Molar mass of chlorine gas = 71 g/mol

Putting values in equation 1, we get:

$\text{Moles of chlorine gas}=\frac{12.45g}{71g/mol}=0.175mol$

The chemical equation for the reaction of hydrogen gas and chlorine gas follows:

$H_2+2Cl_2\rightarrow 2HCl$

By Stoichiometry of the reaction:

1 mole of hydrogen gas reacts with 1 mole of chlorine gas

So, 0.168 moles of hydrogen gas will react with = $\frac{1}{1}\times 0.168=0.168mol$ of chlorine gas

As, given amount of chlorine gas is more than the required amount. So, it is considered as an excess reagent.

Thus, hydrogen gas is considered as a limiting reagent because it limits the formation of product.

Left moles of excess reactant (chlorine gas) = [0.175 - 0.168] = 0.007 moles

By Stoichiometry of the reaction:

1 mole of hydrogen gas produces 2 moles of HCl

So, 0.168 moles of hydrogen gas will produce = $\frac{2}{1}\times 0.168=0.336moles$ of HCl

Now, calculating the mass of HCl and chlorine gas from equation 1, we get:

• For HCl:

Molar mass of HCl = 36.5 g/mol

Moles of HCl = 0.168 moles

Putting values in equation 1, we get:

$0.168mol=\frac{\text{Mass of HCl}}{36.5g/mol}\\\\\text{Mass of HCl }=(0.168mol\times 36.5g/mol)=6.13g$

• For left chlorine gas:

Moles of left chlorine gas = 0.007 moles

Molar mass of chlorine gas = 71 g/mol

Putting values in equation 1, we get:

$0.007mol=\frac{\text{Mass of Chlorine gas}}{71g/mol}\\\\\text{Mass of chlorine gas}=(0.007mol\times 71g/mol)=0.497g$

Hence, the mass of left chlorine gas is 0.497 grams and HCl is 6.13 grams