Determine the mass of oxygen that will be required to obtain magnesium oxide weighing 8 grams.

1. Let’s compose the equation of magnesium oxidation:

2Mg + O2 = 2MgO;

2.Calculate the chemical amount of magnesium oxide:

n (MgO) = m (MgO): M (MgO);

M (MgO) = 24 + 16 = 40 g / mol;

n (MgO) = 8: 40 = 0.2 mol;

3. according to the reaction equation, the amount of oxygen is half that of magnesium oxide, we determine the amount of oxide:

n (O2) = n (MgO): 2 = 0.2: 2 = 0.1 mol;

4.Calculate the mass of oxygen:

m (O2) = n (O2) * M (O2) = 0.1 * 32 = 3.2 g.

Answer: 3.2 g.