Question

quantos mols então contidos em 20g de hidróxido de sódio? (naoh)

Answer 1

NaOH
Na: 23
O: 16
H: 1
--------------------------------
Massa atômica: 40u

1 mol ------ 40g
x mol ------ 20g
x = 0,5 mol

Answer 2

$\mathsf{m_{NaOH}=23+16+1=40g/mol}$

$\mathsf{40g\rightarrow\,1\,mol} \\\mathsf{20g\rightarrow\,k\,mols}$

$\mathsf{40k=20}\\\mathsf{k=\dfrac{20}{40}}\\\boxed{\boxed{\mathsf{k=0,5mols}}}$