Question

04 - Sabendo que a massa molecular do Oxigênio é igual a 16 g/mol, determine o número de átomos desse elemento contidos em 350 mg. (Dado: Número de Avogadro = 6,0 x 10²³).​

Answer 1

$\Large\boxed{\begin{array}{l}\sf 350\,mg=35\cdot10^{-3}\,g=3,5\cdot10^{-2}\,g\\\sf 16\,g\longrightarrow 6\cdot10^{23}\,\acute atomos\\\sf 3,5\cdot10^{-2}\,g\longrightarrow x\\\sf 16x=3,5\cdot6\cdot10^{23}\\\\\sf x=\dfrac{21\cdot10^{23}}{16}\\\\\sf x=1,31\cdot10^{23}\,\acute atomos\end{array}}$