Final answer:
To calculate the number of grams of H₂ produced, convert the mass of H₂ to moles and use the stoichiometry of the Mg and HCl reaction. 0.022 grams of H₂ correspond to 0.011 moles, which in turn suggests that 0.011 moles of Mg and 0.022 moles of HCl were used to produce that amount of H₂.
Step-by-step explanation:
A student asked how many grams of H₂(g) are produced in a reaction where magnesium (Mg) reacts with hydrochloric acid (HCl). To answer this, we use the balanced chemical equation:
Mg(s) + 2 HCl(aq) → MgCl₂(aq) + H₂(g)
Given that 0.022 grams of H₂ are produced, we first need to calculate the number of moles of H₂. The molar mass of H₂ is approximately 2 g/mol, so: 0.022 g H₂ x (1 mol H₂ / 2 g H₂) = 0.011 mol H₂
Using stoichiometry, we can find the moles of Mg and HCl that reacted. Since the ratio of Mg to H₂ and HCl to H₂ in the reaction is 1:1 and 2:1 respectively, 0.011 moles of Mg and 0.022 moles of HCl were needed to produce the given amount of hydrogen gas.
If we instead need to calculate the amount of magnesium chloride (MgCl₂) produced, we would use the stoichiometry of the reaction which tells us that for every mole of Mg reacted, one mole of MgCl₂ is produced.