Question

part: 1 / 2
part 2 of 2
how many moles of hydrogen gas are collected if 2.89 g of magnesium metal is used in the reaction? round your answer to 3 significant digits.
moles of hydrogen gas = \boxed{} mol h₂

Explanation:

Step1: Write the reaction equation

The reaction of magnesium with an acid (e.g., HCl) to produce hydrogen gas is: $Mg + 2HCl = MgCl_2 + H_2$. From the equation, 1 mole of Mg produces 1 mole of $H_2$.

Step2: Calculate moles of Mg

Molar mass of Mg is 24.305 g/mol. Moles of Mg = $\frac{mass}{molar\ mass}$ = $\frac{2.89\ g}{24.305\ g/mol}$ ≈ 0.1189 mol.

Step3: Determine moles of $H_2$

From the reaction, moles of $H_2$ = moles of Mg (1:1 ratio). So moles of $H_2$ ≈ 0.119 mol (rounded to 3 significant digits).

Answer:

0.119