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प्रश्न
If 0.2 mol of the following substance is required how many grams of that substance should be taken?
magnesium oxide
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उत्तर
Molar mass of MgO = 24 + 16 = 40 g/mol
Number of moles of a substance = `"Mass of the substance in grams"/"Molecular mass of the substance"`
Let Mass of the substance in grams be x,
`0.2 = "x"/40 = 8`g
we need, 8g of MgO to obtain 0.2 moles of MgO.
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