How many molecules of SrCrO4 are in a sample of SrCrO4 that has a mass of 24.86 g?
回答 (2)
Molar mass of SrCrO₄ = (87.62 + 52.00 + 16.00×4) g/mol = 203.62 g/mol
No. of moles of SrCrO₄ = (24.86 g) / (203.62 g/mol)
1 mole of SrCrO₄ contains 6.022 × 10²³ molecules.
No. of SrCrO₄ molecules = [(24.86 g) / (203.62 g/mol)] × (6.022 × 10²³ /mol) = 7.35 × 10²²
{SrCrO₄ is an ionic compound. It is better to use "formula units" instead of "molecules"}
1 Find the molecular weight of SrCrO4 = MW
2 Divide 24.86 by MW = mols SrCrO4
3 Multiply mols by Avogadro Constant (6.022x10^23) => number of molecules.
收錄日期: 2021-04-18 14:59:03
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