Question

Convert 31 molecules AI into grams

Answer 1

The atoms of aluminium or Al have a molar mass of 26.98 g/mol. According to the definition, 1 mole of an atomic substance (like Al) contains 6.022·10²³ atoms. Therefore, the number of the moles of Al is:

$n = \frac{31}{6.022·10^{23}mol^{-1}} = 5.15·10^{-23}$ mol.

Finally, the mass of this quantity of Al is:

$m = nM = 5.15·10^{-23}·26.98 = 1.40·10^{-21}$ g.

Answer: the mass of 31 atoms of Al is 1.40·10^-21 g.