Answer:
mass of magnesium oxide is 4.2 grams.
Explanation:
Balanced equation: 2Mg + O2 → 2MgO.
Given that 2.5 g Mg reacts with 3.0 g O2
- mass = moles * Mr
- moles = mass/Mr
- Mr = mass/moles
First find the moles of Mg:
moles = mass/Mr
moles = 2.5/ 24
moles = 0.104 moles
Using molar ratio, magnesium oxide will have same moles as Mg as they both have "2" molar ratio. So moles of Mg is 0.104 moles.
mass = moles * Mr
mass = 0.104 * 40
mass - 4.1667 g
mass = 4.2 g ___________this is the mass of MgO
