Question

ICE TABLE PLEASEEEEE

The oxidation of 100 g of magnesium, Mg, by 50 g of oxygen, O₂, produces 80g of magnesium oxide, MgO.

Draw a chemical spreadsheet to show what happens during the reaction and calculate how many grams of Mg, if any, are left after the reaction.

Calculate the percent yeild to MgO. 2Mg + O₂ ----> 2MgO

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Answer 1

Lets convert masses into moles first:

Mg = 100g / 24.3 g/mol = 4.115 mol

O₂ = 50g /32g/mol = 1.5625 mol

MgO = 80g/40.3044 g/mol = 1.985 mol

ICE table

2Mg + O2 ----> 2MgO

Initially 4.115 mol 1.5625 mol 0

change -2x -x 2x

end 4.115-2x 1.5625-x 2x

we have 2x =  1.985 mol

x =  0.9925 mol

moles of MgO formed from 4.115 mol Mg = 4.115 mol MgO

moles of MgO formed from 1.5625 mol O₂ = 1.5625 x 2 = 3.125 mol MgO from reaction equation

here moles of product formed MgO is less in case of O₂ and hence it is limiting reactant and product yield is based on this

theoretical yield = 3.125 mol MgO

actual yield =   1.985 mol MgO

% = actual yield / theoretical yield x 100 = 63.52 %

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