# How many grams of magnesium are required to react with 2.0 moles of hydrochloric acid?

## Question:

How many grams of magnesium are required to react with {eq}2.0 \ moles {/eq} of hydrochloric acid?

## Mole Ratio of Reactants

Use the balanced reaction in calculating the mole ratio of the reactants. An example of a balanced reaction {eq}aA +bB \rightarrow cC + dD {/eq}. The reactants A and B mole ratio is given as {eq}\dfrac{a}{d} {/eq}. Meaning, the {eq}a {/eq} number of moles of A is required to react completely with the b number of moles of B.

We consider the reaction below for solving the mole number of the reactants and products. That is,

{eq}Mg(s) + 2HCl(aq) \to MgCl_2(aq) + H_2(g) {/eq}

Note that 1 mole of magnesium solid will react 2 moles of {eq}HCl {/eq} completely.

Consider finding the mole number of magnesium solid. That is,

{eq}Mole\ of\ Mg = (2.0\ moles\ HCl) \cdot \left(\dfrac{1\ moles\ Mg}{2\ moles\ HCl}\right)\\ \boxed{Mole\ of\ Mg = 1.0\ mole} {/eq}