Chemistry problem

Question

Liquid hexane (CH3(CH2)4CH3) will react with gaseous oxygen (O2) to produce gaseous carbon dioxide (CO2) and gaseous water (H2O) . Suppose 38. g of hexane is mixed with 96.3 g of oxygen. Calculate the maximum mass of carbon dioxide that could be produced by the chemical reaction. Round your answer to 3 significant digits.

Answer 1

So, there are 2 things you need to look for when doing this type of problem. Usually, when you have a combustion reaction like this, we assume that O2 is in excess, but we are given an exact mass for oxygen gas so that can be thrown out the window. As a result, you would now need to find the limiting reactant. The other thing as always with word problems in chemistry is making sure you have a balanced equation.

Let's start with balancing the equation.

_C6H14 + _O2 ==> _CO2 + _H2O

I recommend that assume there is only one C6H14 and you focus on the carbon first because usually the number of C in the compound is the number of CO2 you produce.

1 C6H14 + _O2 ==> 6CO2 + _H2O

Next, balance the H.

1 C6H14 + _O2 ==> 6 CO2 + 7 H2O

Usually, you would move right onto balancing O, but notice how the H2O has an odd coefficient. This means we will have a odd number of O present on the product side, leaving it hard to balance with just O2 without using fractional coefficient, so I recommend multiplying through by 2

2 C6H14 + _O2 ==> 12 CO2 + 14 H2O

Now, balance O.

2 C6H14 + 19 O2 ==> 12 CO2 + 14 H2O

Now, the rest of the problem is a case of convert the mass of the reactants to moles of reactants. Then, using the coefficients of the balanced equation we just found to find the limiting reactant, in this case: O2. Finally, using the number of moles of the limiting reactant, you would use the coefficients to perform stoichiometry to find the mass of CO2 produced.