Question

Liquid hexane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 3.45 g of hexane is mixed with 16.3 g of oxygen. Calculate the maximum mass of carbon dioxide that could be produced by the chemical reaction. Be sure your answer has the correct number of significant digits.

Answer 1

Write and balance the equation.
Convert g hexane to moles. moles = grams/molar mass.
Likewise for moles oxygen.
Using the coefficients in the balanced equation, convert moles hexane to moles CO2.
Do the same for moles oxygen to moles CO2. You will obtain two different answers; obviously both can't be right. The correct answer in limiting reagent problems is ALWAYS the smaller value and the reagent producing that number is the limiting reagent. Then convert the small number to grams. g = moles x molar mass.

Answer 2

Be sure your answer has the correct number of significant digits..

As both the starting values are to 2 sig figs, and assuming that you use molar masses that have 3 sig figs or greater then the answer should be to 3 sig figs.