What mass of carbon dioxide is produced from the complete combustion of 5.20×10−3 of methane?

Answer 1

is 5.20x10^-3 in moles?
combustion of methane (CH4):
CH4 + O2 --> H2O + CO2
*combustion reaction: products are usually water and carbon dioxide

balance this equation first, then use stoichiometric ratios (the ratio of the moles of CH4 and CO2), to find number of moles of carbon dioxide,,
then multiply this by molar mass of CO2 (which is about 44 g/mol) to get its mass.

hope this helps~