Question

Answer each of the following questions using the equation provided. BE SURE TO BALANCE EACH EQUATION BEFORE SOLVING ANY PROBLEMS. SHOW ALL WORK. ___Mg + ___HCl ___MgCl2 + ___H2 a. What mass of HCl is consumed by the reaction of 2.50 moles of magnesium? b. What mass of MgCl2 is produced if 3.67 moles of HCl react? c. How many moles of hydrogen gas are produced when 3.0 moles of magnesium react?

Answer 1

1 Mg + 2 HCl 1 MgCl₂ + 1 H₂

(a) 182.29 grams HCl

(b) 174.71 grams

(c) .3.0 moles of hydrogen gas

Step-by-step explanation

The unbalanced equation given is:

___Mg + ___HCl ___MgCl2 + ___H2

The balanced equation is

1 Mg + 2 HCl 1 MgCl₂ + 1 H₂

(a) What mass of HCl is consumed by the reaction of 2.50 moles of magnesium?

The first step is to calculate the moles of HCl consumed.

From the balanced equation;

1 mole of Mg consumed 2 moles of HCl

So, 2.50 moles of Mg will consume

`\frac{2.5\text{ }mol\text{ }Mg}{1\text{ }mol\text{ }Mg}*2\text{ }mol\text{ }HCl=5.0\text{ }mol\text{ }HCl`

The final step is to convert 5.0 moles of HCl to mass using the mole formula.

Molar mass of HCl = 36.458 g/mol

`\begin{gathered} Mole=\frac{Mass}{Molar\text{ }mass} \\ \\ \Rightarrow Mass=Mole* Molar\text{ }mass \\ \\ Mass=5.0\text{ }mol*36.458g\text{/}mol \\ \\ Mass=182.29\text{ }grams \end{gathered}`

Therefore, the mass of HCl consumed by the reaction of 2.50 mol of Mg is 182.29 grams.

(b) What mass of MgCl2 is produced if 3.67 moles of HCl react?

Also, the first step is to calculate the moles of MgCl₂ produced.

From the balanced equation;

2 moles of HCl produced 1 mole of MgCl₂

So, 3.67 moles of HCl will produce

`\frac{3.67\text{ }mol\text{ }HCl}{2\text{ }mol\text{ }HCl}*1\text{ }mol\text{ }MgCl_2=1.835\text{ }mol\text{ }MgCl_2`

The final step is to convert 1.835 mol MgCl₂ produced to grams using the mole formula.

Molar mass of MgCl₂ = 95.211 g/mol

`\begin{gathered} Mole=\frac{Mass}{Molar\text{ }mass} \\ \\ Mass=Mole* Molar\text{ }mass \\ \\ Mass=1.835mol*95.211g\text{/}mol \\ \\ Mass=174.71\text{ }grams \end{gathered}`

The mass of MgCl₂ produced is 174.71 grams.

c. How many moles of hydrogen gas are produced when 3.0 moles of magnesium react?

From the balanced equation above;

1 mole of Mg produced 1 mole of H₂

Thus, 3.0 moles of Mg will produce

`\frac{3.0\text{ }mol\text{ }Mg}{1\text{ }mol\text{ }Mg}*1\text{ }mol\text{ }H_2=3.0\text{ }mol\text{ }H_2`

Hence, the moles of H₂ produced is 3.0 moles.