Question

Qual o número de moléculas de H2O presentes em 3 mol dessa substância?

Answer 1

$\Large\boxed{\begin{array}{l}\sf m_{H_2O}=2\cdot1+16=2+16=18\,g/mol\\\sf 18\,g\longrightarrow 6\cdot10^{23}\,mol\acute eculas\\\sf x\longrightarrow 18\cdot10^{23}\,mol\acute eculas\\\sf 6x=18\cdot10^{23}\cdot18\\\sf x=\dfrac{\diagdown\!\!\!\!\!\!\!18\cdot18\cdot10^{23}}{\backslash\!\!\!6}\\\\\sf x=3\cdot18\cdot10^{23}\\\sf x=54\cdot10^{23}\\\sf x=5,4\cdot10^{24}\,mol\acute eculas\end{array}}$