Question

Diatomic O2 can react with the element magnesium to form magnesium oxide (MgO). The balanced chemical equation is: O2 + 2 Mg → 2 MgO If 97.2 g grams of magnesium totally reacted with more than enough O2, how many moles of MgO would be expected to form?

Answer 1

We expected 4 moles of MgO to be formed. (This is 161.2 grams)

Step-by-step explanation:

Step 1: The balanced equation

O2 + 2 Mg → 2 MgO

Step 2: Data given

mass of Mg = 97.2 grams

O2 = in excess

Molar mass of Mg = 24.3 g/mol

Molar mass of O2 = 32 g/mol

Molar mass of MgO = 40.3 g/mol

Step 3: Calculate moles of Mg

moles Mg = 97.2 / 24.3 g/mol

moles Mg = 4 moles

Mg is the limiting reactant. It will completely react (4 moles). O2 is in excess. There will react 2 moles of 02.

Step 4: Calculate moles of MgO

For 2 moles Mg consumed, we need 1 mole O2 to produce 2 moles of MgO

For 4 moles of Mg consumed, we have 4 moles of MgO produced.

We expected 4 moles of MgO to be formed. (This is 161.2 grams)