Answer:

7.85 grams of iron(II) sulfide (FeS) are formed when 5 grams of iron reacts with 5 grams of sulfur.

Explanation:

Let's start with the first question about the limiting reagent for the reaction between ammonia (NH3) and copper(II) oxide (CuO).

1. Calculate the molar masses:

- NH3 (Ammonia) has a molar mass of approximately 17 g/mol (1 nitrogen and 3 hydrogen atoms).

- CuO (Copper(II) oxide) has a molar mass of approximately 80 g/mol (1 copper and 1 oxygen atom).

2. Calculate the moles of NH3 and CuO:

- Moles of NH3 = 3 moles (given)

- Moles of CuO = 5 moles (given)

3. Determine the stoichiometry of the reaction:

- The balanced chemical equation for the reaction between NH3 and CuO is:

2 NH3 + 3 CuO → 3 Cu + 3 H2O

- This equation shows that 2 moles of NH3 react with 3 moles of CuO.

4. Calculate the moles of CuO needed to react with 3 moles of NH3:

- (5 moles of NH3) × (3 moles of CuO / 2 moles of NH3) = 7.5 moles of CuO

Now, compare the actual moles of CuO (5 moles) with the moles needed (7.5 moles). Since you have less CuO than needed, CuO is the limiting reagent in the reaction.

Moving on to the second question about the formation of iron(II) sulfide (FeS) from 5 grams of iron and 5 grams of sulfur:

1. Calculate the molar masses:

- Iron (Fe) has a molar mass of approximately 56 g/mol.

- Sulfur (S) has a molar mass of approximately 32 g/mol.

2. Calculate the moles of iron and sulfur:

- Moles of iron = (5 grams) / (56 g/mol) ≈ 0.0893 moles

- Moles of sulfur = (5 grams) / (32 g/mol) ≈ 0.1563 moles

3. Determine the stoichiometry of the reaction between iron and sulfur:

The balanced chemical equation for the formation of iron(II) sulfide (FeS) is:

Fe + S → FeS

4. The stoichiometry in this equation indicates that 1 mole of iron reacts with 1 mole of sulfur to produce 1 mole of FeS.

5. Calculate the limiting reagent by comparing the moles of iron and sulfur. Since the moles of iron (0.0893 moles) are less than the moles of sulfur (0.1563 moles), iron is the limiting reagent.

6. Calculate the moles of iron(II) sulfide (FeS) formed, which is the same as the moles of iron because of the 1:1 stoichiometry:

Moles of FeS = 0.0893 moles

7. To find the mass of iron(II) sulfide formed, use its molar mass. The molar mass of FeS is approximately 88 g/mol (56 g/mol for Fe + 32 g/mol for S).

Mass of FeS = (0.0893 moles) × (88 g/mol) ≈ 7.85 grams