Answer:
5.62 g of F2
Explanation:
We have to start with the chemical reaction:
[tex]Cl_2~+~3F_2~-->~2ClF_3[/tex]
We have a balanced reaction, so we can continue with the mol calculation. For this, we need to know the molar mass of [tex]Cl_2[/tex] (70.906 g/mol), so:
[tex]3.5~ g~Cl_2 \frac{1~mol~Cl_2}{70.906~g~Cl_2}=0.049~mol~Cl_2[/tex]
Now, with the molar ratio between [tex]Cl_2[/tex] and [tex]F_2[/tex] we can convert from moles of [tex]Cl_2[/tex] and [tex]F_2[/tex] (1:3), so:
[tex]0.049~mol~Cl_2\frac{3~mol~F_2}{1~mol~Cl_2}=0.148~mol~F_2[/tex]
Finally, with the molar mass of [tex]F_2[/tex] we can calculate the gram of [tex]F_2[/tex] (37.99 g/mol), so:
[tex]0.148~mol~F_2\frac{37.99~g~F_2}{1~mol~F_2}=5.62~g~F_2[/tex]
I hope it helps!