At STP how many grams of Mg are required to produce 35 mL of H₂ in the reaction shown below?
Mg(s) + 2 HCl(aq) → H₂(g) + MgCl₂(aq)

Question

At STP how many grams of Mg are required to produce 35 mL of H₂ in the reaction shown below? Mg(s)+ 2 HCl(aq)→ H₂(g)+ MgCl₂(aq) A)0)035 g B)0)038 g C)26 g D)29 g

Quizplus · Accepted Answer

First, we need to calculate the moles of H₂ produced using the ideal gas law: PV = nRT Assuming standard temperature and pressure (STP), we have: (1 atm)(0.035 L) = n(0.0821 L·atm/mol·K)(273 K) n = 0.0015 mol Now we can use stoichiometry to find out how much Mg is needed to produce this amount of H₂: 0.0015 mol H₂ x (1 mol Mg / 1 mol H₂) x (24.31 g Mg / 1 mol Mg) = 0.036 g Mg Rounded to two significant figures, the answer is 0.038 g Mg, which is choice B.

At STP How Many Grams of Mg Are Required to Produce