Stoichiometry Mock Tests

A 20% (w/w) aqueous solution of NaOH has a density of 1.2 g/mL. The molarity of the solution is (Molar mass of NaOH = 40 g/mol):

In a reaction, 3.2 g of methane (CH₄) reacts with excess oxygen. What is the volume of CO₂ produced at STP? (Atomic masses: C = 12, H = 1)

In the reaction MnO₄⁻ + 5Fe²⁺ + 8H⁺ → Mn²⁺ + 5Fe³⁺ + 4H₂O, 0.02 moles of KMnO₄ react completely with Fe²⁺. How many grams of FeSO₄·7H₂O (M = 278 g/mol) were present?

10.0 g of calcium carbonate (CaCO₃) is heated and decomposes completely according to: CaCO₃(s) → CaO(s) + CO₂(g). How many molecules of CO₂ are produced? (Avogadro's number = 6.022 × 10²³ mol⁻¹, molar mass of CaCO₃ = 100 g mol⁻¹)

The number of atoms in 12 g of carbon-12 is:

1.0 g of a mixture of Na₂CO₃ and NaHCO₃ requires 31.86 mL of 0.5 M HCl for complete neutralisation. If NaHCO₃ constitutes 42% by mass of the mixture, what volume of CO₂ is produced at STP? (Molar mass: Na₂CO₃ = 106 g/mol, NaHCO₃ = 84 g/mol)

In the reaction 2H₂ + O₂ → 2H₂O, if 4 moles of H₂ react with 2 moles of O₂, which is the limiting reagent?

In the reaction MnO4- + 5Fe2+ + 8H+ -> Mn2+ + 5Fe3+ + 4H2O, what volume of 0.1 M KMnO4 is required to completely react with 25 mL of 0.5 M FeSO4 solution?