Question

I have a good idea of the answer i just need confirmation! Thanks!

Answer 1

7 moles of MgO was produced during the reaction

EXPLNATION

Given that;

The number of moles of oxygen is 3.5 moles

Follow the steps below to find the number of moles of MgO

Step 1; Write a balanced equation of the reaction

`\text{ 2Mg + O}_2\text{ }\rightarrow\text{ 2MgO}`

In the equation above 2 moles Mg react with 1 mole oxygen to produce 2 moles MgO

Step 2; Find the number of moles of MgO using a stoichiometry ratio

Let x represents the number of moles of MgO

`\begin{gathered} \text{ 1 mole O}_2\text{ }\rightarrow\text{ 2 moles MgO} \\ \text{ 3.5 moles O}_2\text{ }\rightarrow\text{ x moles MgO} \\ \text{ Cross multiply} \\ \text{ 1 mole O}_2*\text{ x moles MgO = 2 moles MgO }*\text{ 3.5moles O}_2 \\ \text{ Isolate x} \\ \text{ x moles MgO = }\frac{2\text{ moles MgO}*3.5moles\cancel{O_2}}{1mole\cancel{O_2}} \\ \\ \text{ x moles MgO = 2 }*\text{ 3.5} \\ \text{ x moles of MgO = 7 moles} \end{gathered}`

Therefore, 7 moles of MgO was produced during the reaction