Question

For the following reaction, calculate how many moles of each product are formed when 0.356 moles of PbS completely react. Assume there is an excess of oxygen.
2PbSs+3O2g→2PbOs+2SO2g

Answer 1

Answer:

0.356 moles of each products (PbO and SO2) are formed.

Explanation:

First step is to write out the equation and ensure it is balanced before proceeding.

2PbSs + 3O2g → 2PbOs + 2SO2g

2            3            2              2

The equation above is balanced because there are equal number of atoms of elemenents on both sides of the arrow.

By stating that oxygen is in excess, this tells that PbS is the limiting reactant (i.e the amount of products formed depends on it) and not on oxygen.

From the equation;

The products formed are PbO and SO2.

For PbO, it requires 2 moles of PbS to react completely in order to form 2 moles of PbO.

For SO2, it requres 2 moles of PbS to react completely in order to form 2 moles of SO2.

This is gotten from the equation.

PbO

2 moles = 2 moles

0.356 moles = x

upon cross multiplication, we are left with;

x = (0.356 * 2) / 2 = 0.356 moles

SO2

2 moles = 2 moles

0.356 moles = x

upon cross multiplication, we are left with;

x = (0.356 * 2) / 2 = 0.356 moles

Answer 2

Answer:

When 0.356 moles of PbS completely react 0.356 moles of PbO and 0.356 moles of SO₂ are produced.

Explanation:

2PbS (s) + 3O₂ (g) → 2PbO (s) + 2SO₂ (g)

2 mol PbS ____________ 2 mol PbO

0.356 mol PbS ________         x

          x = 0.356 mol PbO

2 mol PbS ____________ 2 mol SO₂

0.356 mol PbS ________         x

          x = 0.356 mol SO₂