Question

When methane (CH4) burns, it reacts with oxygen gas to produce carbon dioxide and water. The unbalanced equation for this reaction is CH4(g)+2O2(g)→CO2(g)+2H2O.What mass of carbon dioxide is produced from the complete combustion of 4.50×10−3 g of methane?

Answer 1

Molar mass of CH4,

MM = 1*MM(C) + 4*MM(H)

= 1*12.01 + 4*1.008

= 16.042 g/mol

mass(CH4)= 4.50*10^-3 g = 0.00450 g

number of mol of CH4,

n = mass of CH4/molar mass of CH4

=(0.00450 g)/(16.042 g/mol)

= 2.805*10^-4 mol

Balanced chemical equation is:

CH4 + 2 O2 ---> CO2 + 2 H2O

Molar mass of CO2,

MM = 1*MM(C) + 2*MM(O)

= 1*12.01 + 2*16.0

= 44.01 g/mol

According to balanced equation

mol of CO2 formed = (1/1)* moles of CH4

= (1/1)*0.0003

= 0.0003 mol

mass of CO2 = number of mol * molar mass

= 2.805*10^-4*44.01

= 1.24*10^-2 g

Answer: 1.24*10^-2 g