Answer:

Explanation:
They gave us the masses of two reactants and asked us to determine the mass of the product.
This looks like a limiting reactant problem.
1. Assemble the information
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 239.27 32.00 207.2
2PbS + 3O₂ ⟶ 2Pb + 2SO₃
m/g: 2.54 1.88
2. Calculate the moles of each reactant

3. Calculate the moles of Pb from each reactant

4. Calculate the mass of Pb

B: Painting over a metal surface in order to prevent rust is known as
rust proofing and it works by preventing oxygen and water from reaching
the metal surface thus preventing a redox reaction which would result in
rusting.
Answer: By Stoichiometry, 3 moles of chlorine gas reacts with 6 moles of sodium hydroxide solution to form 5 moles of sodium chloride, 1 mole of sodium chlorate (V) and 3 moles of water. Hence, the reaction between chlorine gas and hot, concentrated NaOH solution yields Sodium chloride and sodium chlorate(V).
Explanation: Hope it helps :)
Honestly just look at the question deeper and find it inside the equation of the fraction