Oxygen gas
128g
Explanation:
Given parameters:
Number of moles of Mg = 3.20moles
Number of moles of oxygen = 3.34moles
Unknown:
Excess element = ?
Mass of the product formed = ?
Solution:
To solve this problem, we must understand that the extent of the reaction depends on the limiting reactant.
It is the reactant whose given quantity is in short supply in the reaction.
Equation of the reaction:
2 Mg + O₂ = 2MgO
from the balanced equation:
2 mole of Mg reacts with 1 mole of oxygen gas;
3.2 moles of Mg will require = 1.6moles of oxygen gas
But we were given 3.34 moles of oxygen gas, this is in excess.
The liming reactant is then Mg;
2 mole of Mg gives 2 moles of MgO
3.2mole of Mg will give 3.2 mole of MgO
Mass of MgO = Number of moles x molar mass
Molar mass of MgO = 24 + 16 = 40g/mol
Mass of MgO = 3.2 x 40 = 128g
learn more:
Number of moles brainly.com/question/1841136
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