What volume of hydrogen is produced at s.t.p. When 2.60 g of zinc reacts with excess HCI according to the following equation? Zn(s) + 2HCI(aq) → ZnCI 2(aq) ...

Assessment: WAEC SSCE - Chemistry - 1999 (Objective) Subject: Chemistry

Question 1 Report

What volume of hydrogen is produced at s.t.p. When 2.60 g of zinc reacts with excess HCI according to the following equation? Zn(s) + 2HCI(aq) → ZnCI 2(aq) + H2(g) [Zn = 65; 1 mole of a gas occupies 22.4dm3 at s.t.p]
Answer Details
The balanced chemical equation is: Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g) First, we need to find the moles of zinc present: m(Zn) = 2.60 g M(Zn) = 65 g/mol (molar mass of Zn) n(Zn) = m(Zn) / M(Zn) n(Zn) = 2.60 g / 65 g/mol n(Zn) = 0.04 mol According to the balanced equation, 1 mole of zinc reacts with 2 moles of hydrochloric acid to produce 1 mole of hydrogen gas. Since we have an excess of hydrochloric acid, all the zinc will react, and the amount of hydrogen produced can be calculated as follows: n(H2) = n(Zn) × 1 mol H2 / 1 mol Zn n(H2) = 0.04 mol Now we can use the ideal gas law to find the volume of hydrogen produced at STP: PV = nRT where P is the pressure (which is 1 atm at STP), V is the volume, n is the number of moles, R is the gas constant (0.08206 L·atm/mol·K), and T is the temperature (273 K at STP). Solving for V: V = nRT / P V = (0.04 mol) × (0.08206 L·atm/mol·K) × (273 K) / (1 atm) V = 0.89 L V = 0.89 dm3 (since 1 L = 1 dm3) Therefore, the volume of hydrogen produced at STP is 0.89 dm3, which is option (B).

Download The App On Google Playstore

Everything you need to excel in your exams

Green Bridge CBT Mobile App
Personalized AI Learning Chat Assistant
200,000+ Exam Questions Across IGCSE, JAMB, WAEC & NECO
Over 3,900 Lesson Notes
Offline Support - Learn Anytime, Anywhere
Green Bridge Timetable
Literature Summaries & Potential Questions
Track Your Performance & Progress
In-depth Explanations for Comprehensive Learning