Question

A chemistry student has 5 g of magnesium (Mg) and 10 g of hydrochloric acid (HCl) to react. What mass of magnesium chloride (MgCl2) will be produced? (Assuming the reaction goes to completion and all the reactants are used up)

Answer 1

The balanced chemical equation for the reaction between magnesium and hydrochloric acid is:Mg + 2HCl  MgCl2 + H2First, we need to determine the limiting reactant. To do this, we'll calculate the moles of each reactant and compare their mole ratios.Moles of Mg = mass / molar massMoles of Mg = 5 g /  24.31 g/mol   0.206 molMoles of HCl = mass / molar massMoles of HCl = 10 g /  36.46 g/mol   0.274 molNow, we'll compare the mole ratios of Mg and HCl to the balanced equation:Mg:HCl = 0.206 mol : 0.274 mol = 1 : 1.33According to the balanced equation, the mole ratio of Mg to HCl should be 1:2. Since the ratio is 1:1.33, magnesium is the limiting reactant.Now, we can calculate the moles of MgCl2 produced using the stoichiometry of the balanced equation:Moles of MgCl2 = moles of Mg  limiting reactant  = 0.206 molFinally, we can calculate the mass of MgCl2 produced:Mass of MgCl2 = moles of MgCl2  molar mass of MgCl2Mass of MgCl2 = 0.206 mol   95.21 g/mol   19.6 gSo, approximately 19.6 g of magnesium chloride  MgCl2  will be produced.