I am studying for a big test and I ran across something that I couldn't solve no matter how hard I tried. (reading through old tests)

Burning ethanol produces carbon dioxide ($\ce{CO2}$) and water ($\ce{H2O}$).

a) Write down a balanced chemical equation that illustrates the complete burning of ethanol.

b) What is the mass of produced carbon dioxide ($\ce{CO2}$), when completely burning 575 liters of ethanol?

NTP conditions apply. Ethanols density is 0.8 g/cm³.

MC = 12 g/mol, MH = 1 g/mol, MO = 16 g/mol

For the first part I came up with $\ce{C_2H_6O (l) + 3O2(g) --> 2CO_2 (g) + 3H2O (g)}$

Then I calculated that $M_\ce{CO_2}$ = 44 g/mol and $M_\ce{H_2O}$ = 18 g/mol

I also calculated that 575 liters of ethanol weighs 460 kg

I know that m = nM

However I am not sure what to do next. I may also be using some weird terms here as this is my translation and I've never dealt with math/chemistry in English.


2 Answers 2


Ethanol's molecular mass $M(\ce{C2H6O})=46\ \mathrm{g/mol}$

$$n=\frac mM,$$ so $$\frac{460\,000\ \mathrm g}{46\ \mathrm{g/mol}} = 10\,000\ \mathrm{mol}$$

So having 10 000 moles we can multiply that by the molecular mass of carbon dioxide and multiply again by two because there are two carbon dioxides.

$$10\,000\ \mathrm{mol}\times44\ \mathrm{g\ mol^{-1}}\times2=880\,000\ \mathrm g=880\ \mathrm{kg}$$


1.u can easily analyse that 1mole of etanol produces 2 moles co2. 2.so first calculate M for ethanol=46g/mol. 3.m calculated by u for C2H5OH is 460000gm 4.so no of moles=m/M=460000/46=10000 moles. 5.now 1mole C2H5OH produces 2mole co2 so using unitary method 10000 moles of C2H5OH will produce=10000×2 Co2 moles. 6.molecular mass of co2=44g/mol,20000 moles=20000×44=880000gm=880kg of co2 is ur ans.


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