Question

1)Calcule a quantidade de matéria (mols) existentes em (consulte
uma tabela de massas atômicas):
a) 20 g de hidróxido de sódio (NaOH)
b) 18 g de alumínio (Al)
c) 9 g de glicose (C6H12O6)

Answer 1

$\large\boxed{\begin{array}{l}\rm a)\\\sf 50\,g\longrightarrow 1\,mol\\\sf 20\,g\longrightarrow x\,mols\\\sf 50x=20\\\sf x=\dfrac{2\backslash\!\!\!0}{5\backslash\!\!\!0}\\\\\sf x=0,4\,mols\\\rm b)\\\sf 27\,g\longrightarrow 1\,mol\\\sf 18\,g\longrightarrow y\,mols\\\sf 27y=18\\\sf y=\dfrac{18}{27}\\\\\sf y=0,66\,mols\end{array}}$

$\large\boxed{\begin{array}{l}\rm c)\\\sf 180\,g\longrightarrow 1\,mol\\\sf 9\,g\longrightarrow x\\\sf 180x=9\\\sf x=\dfrac{9}{180}\\\\\sf x=0,05\,mols\end{array}}$