The propane undergoes a combustion reaction (combustion reactions are reactions in which a substance reacts with oxygen and burns).
To calculate the number of moles of propane, we use the molar mass of propane, which is 44.0 g/mol.
[tex](6804g\ C_3H_8)(\frac{1mol\ C_3H_8}{40.0g\ C_3H_8})=170.1mol\ C_3H_8[/tex]
To convert mol C3H8 into mol CO2, we use the molar ratio between the two substances. The molar ratio is seen by the coefficients in front of the each substance in the reaction, so the ratio of C3H8 to CO2 is 1 to 3, with 3 moles of CO2 produced for every mole of C3H8 reacting.
[tex](170.1mol\ C_3H_8)(\frac{3mol\ CO_2}{1mol\ C_3H_8})=510.3mol\ CO_2[/tex]
To convert mol CO2 into molecules of CO2, we use Avogadro's number:
There are 6.022 × 10²³ molecules per mole of any substance:
[tex](510.3mol\ CO_2)(\frac{6.022*10^{23}mlcs\ CO_2}{mol\ CO_2})=3.07*10^{26}molecules\ CO_2[/tex]