X (g) + F2 (g) ---> XF2 (g) Jika 126 g gas X tepat habis bereaksi dgn 57 g gas fluorin (Ar F=19) , Ar X adalah ....

[tex]\displaystyle \text{X}_{(g)}+\text{F}_2_{(g)}\to\text{XF}_2_{(g)}\\\\n\text{ F}_2=n\text{ X}\\\frac{m}{\text{Ar F}_2}=\frac{m}{\text{Ar X}}\\\frac{57}{38}=\frac{126}{\text{Ar X}}\\\frac{3}{2}=\frac{126}{\text{Ar X}}\\\frac{1}{2}=\frac{42}{\text{Ar X}}\\\boxed{\boxed{\text{Ar X}=84}}}[/tex]