Question

What volume of sulfur dioxide gas is produced at STP when 40.0 grams of sulfur is burned in excess oxygen

Answer 1

$S+O_2\to SO_2$

we can see that the stochiometric coefficients of Sulfur and sulfur-dioxide is same

which means that moles of sulfurdioxide formed will be equal to the moles of sulfur burned

moles of sulfur present = $\frac{40}{32}=1.25$

moles of sulfur dioxide formed = 1.25

as 1 mole is equivalent to 22.4 litres

hence, 1.25 moles is equivalent to 1.25$\times$22.4 litres =28 litres