Question

`"Sn" + 2"HF" to "SnF"_2 + "H"_2` How many grams of hydrogen are produced from the reaction of `30.00 g` of `"HF"`?

Answer 1

`1.5g`

Explanation:

First, we need the number of moles of `"HF"` being used:
`n("HF")=(m("HF"))/(M_r("HF"))=30/20=3/2=1.5mol`

`((n("HF"),:,n("H"_2)),(2,:,1))`

So, we need to half the number of moles:
`n("H"_2)=1.5/2=0.75mol`

`m("H"_2)=n("H"_2)M_r("H"_2)=0.75*2=1.5g`