A student is working in a lab at school.He combines 40 grams of magnesium oxide (MgO) with 25 grams of lithium fluoride (LiF). MgO+2LiFarrow MgF_(2)+Li_(2)O After the reaction is complete, he still has some unreacted MgO left over. Which one of the following statements is true? LiP was the limiting reactant because it ran out causing the reaction to stop. MgO was the limiting reactant because there are not enough moles to complete the reaction. MgO was the limiting reactant because there is still some unreacted MgO leftover. LIF was the limiting reactant because you started with less of it.

## Step 1: Calculate moles of MgOMgO has a molar mass of approximately . Calculate the moles of MgO. ## Step 2: Calculate moles of LiFLiF has a molar mass of approximately . Calculate the moles of LiF. ## Step 3: Determine limiting reactantThe balanced equation is From the equation, 1 mole of MgO requires 2 moles of LiF. Since we have fewer moles of LiF than required (0.962 mol) to react with 1 mole of MgO, LiF is the limiting reactant.## Step 4: Analyze remaining MgOAfter the reaction, some MgO is left unreacted. This further confirms that LiF was completely consumed.