JPJC 2026 Mole & Stoichiometry MCQ

Jurong Pioneer Junior College 2026 JC1 H2 Chemistry: The Mole Concept and Stoichiometry 1 JURONG PIONEER JUNIOR COLLEGE 2026 JC1 H2 Chemistry (9476) MCQ Quiz Topic 2: The Mole Concept & Stoichiometry Name : __________________________________________ 5 Class : 26S________________ Date : ____________ Duration : 10 minutes Answer all questions. For each question there are four possible answers, A, B, C and D. Choose the one you consider correct and indicate your answers in the brackets provided. 1 ‘Solder glass’ is composed of 16% boron oxide, B 2O3, by mass, and 84% lead( II) oxide, PbO, by mass. What is the Pb/B molar ratio in ‘solder glass’? A 0.82 B 0.91 C 1.22 D 1.64 ( ) 2 Analysis of a mixture of two sulfur –containing gases shows that hydrogen sulfide, H 2S, and carbon disulfide, CS2, are present in a 2 : 1 mole ratio. This mixture is burned in excess oxygen. What will the SO2 : CO2 mole ratio in the mixture obtained after complete combustion? A 1 : 1 B 2 : 1 C 3 : 1 D 4 : 1 ( )

2 3 10 cm3 of a gaseous hydrocarbon X was exploded in excess oxygen. Upon cooling to room temperature, there was a contraction in volume of 35 cm3. When the products were treated with excess KOH(aq), there was a further contraction of 40 cm3. What is the molecular formula of hydrocarbon X? [All gaseous volumes are measured under identical conditions at r.t.p.] A C2H4 B C4H8 C C4H10 D C4H12 ( ) 4 The manufacture of calcium carbide involves the following reaction: CaO(s) + 3C(s) → CaC2(s) + CO(g) What is the maximum mass of calcium carbide (in kg) that can be obtained from 40.0 kg of calcium oxide and 40.0 kg of coke (carbon)? A 13.3 B 40.0 C 45.7 D 71.2 ( ) 5 25.0 cm3 of 0.05 mol dm−3 KClO4(aq) required 50.0 cm3 of 0.20 mol dm−3 TiCl3 (aq) to reach the end–point in a titration. Given that titanium(III) is oxidised to titanium(IV) in this reaction, which one of the following formulae correctly represents the reduction product of the ClO4− ion? A ClO− B Cl− C ClO2− D ClO3− ( )