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Question
Calculate the number of moles of magnesium present in a magnesium ribbon weighing 12 g. Molar atomic mass of magnesium is 24g mol–1.
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Solution
Atomic mass of Mg = 24 g mol-1
24 g of Mg = 1 mol
12 g of Mg = `12/24`
= 0.5 mol
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| Species Property | H2O | CO2 | Na atom | MgCl2 |
| No. of moles | 2 | - | - | 0.5 |
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| Mass | 36g | - | 115 g | - |
