Question

calculate the number of moles of magnesium oxide, MgO in
1. 80g of the compound
2. 10g of the compound (average atomic mass of Mg=24 and O=16)
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Answer 1

Answer:

The answer is "2 moles and 0.25 moles"

Step-by-step explanation:

The formula to calculate number of moles is:

No. of moles = mass of substance/Molar mass of substance

Molar mass of MgO = mass of Mg + Mass of O = 24 + 16 = 40 g/mole

1- No of moles of magnesium oxide in  80 g of the compound  

No. of moles = 80 / 40 = 2 moles

2- No of moles of magnesium oxide in  10 g of the compound  

No. of moles = 10/40 = 0.25 moles