A mixture containing 6.4 g of sulfur dioxide and 3.2 g of oxygen undergoes the reaction 2SO₂ + O₂ → 2SO₃, assuming complete reaction, calculate the mass of sulfur trioxide produced:

1. 32 g
2. 16 g
3. 8 g
4. 4 g

Which of the following is the molality of a 20% (by mass) \(\mathrm{CaCO_3}\)solution?
\((\text{Given: Density of the solution} = 1.2\ \text{g mL}^{-1})\)

What is the ratio of the number of atoms in 2.2 g of CO₂ and in 1.7 g of NH₃?

An organic compound has the following composition by mass: C = 40.687%, H = 5.085%, O = 54.228%. Given vapour density = 59, find its molecular formula.

1. C₄H₆O₄

2. C₄H₆O₂

3. C₄H₄O₂

4. None of the above

Calculate the total molarity of all the ions present in a solution containing 0.1 M of CuSO₄ and 0.1 M of Al₂(SO₄)₃.

1. 0.2M

2. 0.7M

3. 0.8M

4. 1.2M

Calculate the change in volume when 100 mL of phosphine ( PH₃) decomposes completely into phosphorus and hydrogen.

An element X occurs naturally as three isotopes with the following abundances:

²⁰⁰X = 90%, ¹⁹⁹X = 8%, and ²⁰²X = 2%.

What is the approximate average atomic mass of element X?

For the reaction:

4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(l)

If 1 mol of NH₃ is mixed with 1 mol of O₂ and the reaction proceeds to completion, which of the following statements is correct?

Find the unreacted reactant and its remaining mass after the complete reaction of 1 g of
magnesium with 0.56 g of oxygen in a closed vessel.

(Given: Atomic masses: Mg = 24 u, O = 16 u)

What is the mole fraction of the solute in a 1.00 molal aqueous solution?