Question

Use the formula to answer the following question4Li + Pb(SO4)2->2Li₂SO4 + PbHow many moles of Pb(SO4)2 are needed to produce 330 g Li₂SO4?

Answer 1

ANSWER

The number of moles of Pb(SO4)2 is 1.5 moles

EXPLANATION

Given that;

The mass of Li2SO4 is 330g

Follow the steps below to find the moles of Pb(SO4)2

Step 1; Write the balanced equation of the reaction

$\text{ 4Li + Pb\lparen SO}_4)_2\rightarrow\text{ 2Li}_2SO_4\text{ + Pb}$

Step 2; Find the number of moles of Li2SO4 using the below formula

$\text{ Mole = }\frac{\text{ mass}}{\text{ molar mass}}$

Recall, that the molar mass of Li2SO4 is 109.94 g/mol

$\begin{gathered} \text{ mole = }\frac{\text{ 330}}{\text{ 109.94}} \\ \text{ mole = 3.00 moles} \end{gathered}$

The number of moles of Li2SO4 is 3.00 moles

Step 3; Find the number of moles of Pb(SO4)2 using a stoichiometry ratio

In the above equation of the reaction, 1 mole Pb(SO4)2 reacts to give 2 moles LiSO4

Let the number of moles of Pb(SO4) be x

$\begin{gathered} \text{ 1 mole Pb\lparen SO}_4)_2\text{ }\rightarrow\text{ 2 moles Li}_2\text{SO}_4 \\ \text{ x moles Pb\lparen SO}_4)_2\text{ }\rightarrow\text{ 3.00 moles Li}_2SO_4 \\ \text{ Cross multiply} \\ \text{ 1 mole Pb\lparen SO}_4)_2\text{ }\times\text{ 3 .00 moles Li}_2SO_4\text{ = 2 moles Li}_2SO_4\text{ }\times\text{ x moles Pb\lparen SO}_4)_2 \\ \text{ Isolate x} \\ \text{ x = }\frac{\text{ 1 mole Pb\lparen SO}_4)_2\times3moles\cancel{Li_2}SO_4}{2moles\cancel{Li_2}SO_4} \\ \text{ x = }\frac{1\text{ }\times\text{ 3}}{2} \\ \text{ x = }\frac{3}{2} \\ \text{ x = 1.5 moles} \end{gathered}$

Therefore, the number of moles of Pb(SO4)2 is 1.5 moles