Question #7152a

1 Answer
Dec 12, 2014

In order to solve these kinds of problems, one must always use the balanced chemical equation and the ideal gas law, PV = nRTPV=nRT.

The balanced equation given is

2C_4H_(10(g)) + 13O_(2(g)) -> 8CO_(2(g)) + 10H_2O((l))2C4H10(g)+13O2(g)8CO2(g)+10H2O((l))

Notice that we have 2:82:8 (or a 1:41:4) mole ratio between C_4H_10C4H10 and CO_2CO2; this means that for every mole of C_4H_10C4H10 used in the reaction, 4 moles of CO_2CO2 will be produced.

Now, since we don't have a mass or a number of C_4H_10C4H10 to go by, let's assume we start with 10.0g10.0g of butane. Knowing that butane's molar mass is 58g/(mol)58gmol, we can determine the number of moles from

n_(butane) = m/(molarmass) = (10.0g)/(58g/(mol)) = 0.17nbutane=mmolarmass=10.0g58gmol=0.17 moles.

We thus get n_(CO_2) = 4 * n_(bu t an e) = 0.68nCO2=4nbutane=0.68 moles.

So, the volume produced in this case is

V = (nRT)/P = (0.68 * 0.082 * (273.15+23))/1.00 = 16.5LV=nRTP=0.680.082(273.15+23)1.00=16.5L

This method can be used for any mass of butane given...