How do you calculate the number of molecules in a substance?

Question

Owen Ambrose · Accepted Answer

Divide the mass of the molecular substance by its molar mass to get moles. Then multiply times #(6.022xx10^23"molecules")/(1"mol")#.

Determine the mass of the substance, and its molar mass. Divide the given mass by its molar mass to get moles, then multiply times #(6.022xx10^23"molecules")/(1"mol")#. Example How many molecules are contained in 25.00 g glucose #("C"_6"H"_12"O"_6")#? Molar mass #"C"_6"H"_12"O"_6"##=##"180.15588 g/mol"# https://tutor.hix.ai #25.00cancel("g C"_6"H"_12"O"_6)xx(1cancel("mol C"_6"H"_12"O"_6))/ (180.15588cancel("g C"_6"H"_12"O"_6))xx(6.022xx10^23"molecules")/(1cancel("mol C"_6"H"_12"O"_6"))##=##"8.357 molecules C"_6"H"_12"O"_6"#

Caleb Adams · Answer

undefined Avogadro's number, or roughly $6.022 \times 10^{23}$ molecules per mole, can be used to calculate the number of molecules in a substance. Simply multiply the number of moles of the substance by Avogadro's number.

Naomi Aronson · Answer

undefined To calculate the number of molecules in a substance, use the formula:

$$ \text{Number of molecules} = \frac{\text{Mass of the substance (g)}}{\text{Molar mass of the substance (g/mol)}} \times \text{Avogadro's number} $$

Avogadro's number is $6.022 \times 10^{23}$ molecules/mol, which represents the number of units in one mole of any substance.

1. **Determine the mass of the substance** in grams.
2. **Find the molar mass** of the substance (the mass of one mole of the substance, found on the periodic table, in g/mol).
3. **Divide the mass of the substance** by its molar mass to find the number of moles.
4. **Multiply the number of moles** by Avogadro's number to find the number of molecules.