Question

Diatomic O2 can react with the element magnesium to form magnesium oxide (MgO). The balanced chemical equation is: 2Mg + O2 → 2MgO If 4 moles of magnesium totally reacted with more than enough O2, how many moles of MgO would be expected to form?a. 8 moles
b. 4 moles
c. 2 moles
d. not enough information
e. 1 mole

Answer 1

Answer:

We will expect 4 moles of MgO to be formed (option b).

Explanation:

Step 1: The balanced equation

2Mg + O2 → 2MgO

Step 2: Data given

Number of moles of Magnesium = 4 moles

Oxygen = in excess  → this means Magnesium is the limiting reactant

Magnesium will completely be consumed ( 4 moles). There will remain 0 moles.

For 2 moles of magnesium consumed, we need 1 mole of oxygen to produce 2 moles of MgO.

For 4 moles of magnesium, we need 4/2 = 2 moles of oxygen.

For 4  moles of magnesium, we will produce 4/1 = 4 moles of MgO

We will expect 4 moles of MgO to be formed (option b).