Question

03.Qual a quantidade de mol em: a) 20 g de He b) 0,5 mol de CH4 c) 5,5 mols de Cl2​

Answer 1

$\Large\boxed{\begin{array}{l}\tt a)~\sf 4~g\longrightarrow 1~mol\\\sf 20~g\longrightarrow x\\\sf 4x=20\\\sf x=\dfrac{20}{4}\\\sf x=5~mols\\\tt b)~\sf 16~g\longrightarrow 1~mol\\\sf x\longrightarrow 0,5~mol\\\sf x=16\cdot0,5\\\sf x=8~g\\\tt c)~\sf70~g\longrightarrow 2~mol\\\sf x\longrightarrow 5,5~mols\\\sf 2x=5,5\cdot70\\\sf x=\dfrac{5,5\cdot\diagdown\!\!\!\!\!70}{\diagdown\!\!\!2}\\\sf x=5,5\cdot35\\\sf x=192,5~g\end{array}}$