128g of sulphur are burned in excess oxygen. What mass of sulphur dioxide forms? S + O2 --> SO2 *

Mass of Sulphur dioxide : 256 g

Given

Reaction

S + O2 --> SO2 *

Required

Mass of Sulphur dioxide

Solution

mol of Sulphur (Ar=32 g/mol) :

mol = mass : Ar

mol = 128 : 32

mol = 4

From the equation, mol ratio S : SO2 = 1 : 1, so mol SO2 = 4

Mass of SO2 :

mass = mol x MW SO2

mass = 4 x 64

mass = 256 g