What mass of carbon dioxide is produced from the complete combustion of 4.80×10−3 g of methane?

 The mass  of carbon dioxide produced  from  the  complete   combustion  of  4.80  x10^-3 g  of methane  is  0.0132  grams

         calculation
write the equation for combustion of methane (CH4)

CH4 + 2O2 → CO2 + 2H2O

find the moles  of   CH4 used  =  mass/molar mass
molar mass of CH4  =  12 +(1 x4) = 16 g/mol

moles   =( 4.80  x10^-3 g)  / 16  g/mol = 3 × 10^-4  moles

by use of mole ratio  between   Ch4 to CO2   which is 1:1 the moles of CO2 is also =  3 x10^-4  moles

mass of CO2 is therefore =  moles x molar mass  of Co2
 
The molar mass of Co2 = 12 +(16 ×2) = 44 g/mol

mass  is therefore =   (3 ×10^-4   moles)  ×44  g/mol  = 0.0132 grams