Calculate moles from provided weight
4. Moles and Molarity 4.1) Moles 4.1.1) Moles - General
4.1.1.1) Moles - General Normal 1
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A compounder weighed 324.81 mg of magnesium sulfate heptahydrate . If the molecular weight of magnesium sulfate heptahydrate is 120.3 g/mol, then determine the number of milimoles present there.
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lb equals 2.7 mmol kg
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The molecular weight of magnesium sulfate heptahydrate is 120.3 g/mol, which means `(120.3 \quad g)/(1 \quad mol)`. Again, 324.81 mg equals `324.81/1000=0.32481` g of magnesium sulfate heptahydrate . Therefore, using equation method we can write:
`(120.3 \quad g)/(1 \quad mol)=(0.32481 \quad g)/x therefore x = 0.0027` mol.
Multiplying this number with 1000 will give us milimoles;
`therefore 0.0027 × 1000 = 2.7` mmol. Ans.
Using shortcut: simply divide the miligram weight (`324.81 \quad mg`) with molecular weight (`120.3\quad g/(mol)`). This will give us:
`(324.81 \quad mg)/(120.3 \quad g/(mol))=2.7 \quad mmol` Ans.