Question

When carbon is burned in air, it reacts with oxygen to form carbon dioxide. When 26.4 g of carbon were burned in the presence of 83.8 g of oxygen, 13.4 g of oxygen remained unreacted. What mass of carbon dioxide was produced?

Answer 1

the combustion reaction of Carbon and oxygen is C+ O2------->CO2 (1)

1 mole of Carbon requires 1 mole of oxygen to produce 1 mole of CO2.

moles= mass/molar mass

molar mass or atomic mass ( g/mole) C:12, and O=16

moles : C= 26.4/12= 2.2, Oxygen reacted = oxygen supplied -oxygen remaied = 83.8-13.4 =70.4 gm, moles of Oxygen consumed = mass of oxygen/molar mass= 70.4/32=2.2

this is same as moles of Carbon. Hence moles of CO2 formed = 2.2 moles from reaction-1

mass of CO2 produced= moles of CO2* molar mass = 2.2*44 =96.8 gm