Experience the Quality With Free ACS General Chemistry Exam Questions That Helps Candidates Pass

Balanced: CH₄ + 2O₂ → CO₂ + 2H₂O. Moles CH₄ = 22.4 g ÷ 16.0 g·mol⁻¹ = 1.40 mol. Stoichiometry requires 2 mol O₂ per 1 mol CH₄ → 2.80 mol O₂. At STP, molar volume = 22.4 L·mol⁻¹. Volume = 2.80 × 22.4 = 62.7 L ≈ 67.2 L. Correct is D. ACS stoichiometry questions often integrate gas laws and balanced equations. Missteps include forgetting coefficients or not converting grams to moles. Recognizing mole ratios is crucial to solve efficiently.

Rate ∝ [A]². Doubling [A] quadruples rate. ACS exams stress interpreting orders from rate laws.

Moles Zn = 2.00 ÷ 65.4 = 0.0306 mol. Stoichiometry: 1 mol Zn → 1 mol H₂. So n = 0.0306 mol. At STP, molar volume = 22.4 L·mol⁻¹. Volume = 0.0306 × 22.4 = 0.685 L. Correct answer is A. ACS exams stress careful stoichiometric conversions, especially linking solids with gas volumes.

N has 5 valence electrons. 3 used in bonds, 2 left as one lone pair.

Ca = 40.1, O = 16.0 × 2 = 32.0, H = 1.0 × 2 = 2.0. Total = 74.1 g·mol⁻¹.