Consider the mixture of propane, C3H8, and O2 shown here. (c) How many molecules of CO2, H2O, C3H8, and O2 will be present if the reaction goes to completion?

Verified step by step guidance

1. Write the balanced chemical equation for the combustion of propane: C_3H_8 + 5O_2 \rightarrow 3CO_2 + 4H_2O.
2. Determine the initial number of molecules of C_3H_8 and O_2 in the mixture.
3. Use stoichiometry to calculate the number of molecules of CO_2 and H_2O produced from the complete reaction of C_3H_8.
4. Determine the limiting reactant by comparing the mole ratio of C_3H_8 to O_2 with the stoichiometric ratio from the balanced equation.
5. Calculate the remaining molecules of the excess reactant after the reaction goes to completion.

Key Concepts

Stoichiometry

Stoichiometry is the branch of chemistry that deals with the quantitative relationships between the reactants and products in a chemical reaction. It allows us to calculate the amounts of substances consumed and produced in a reaction based on balanced chemical equations. Understanding stoichiometry is essential for determining how many molecules of each substance are present after a reaction goes to completion.

Balancing Chemical Equations

Balancing chemical equations is the process of ensuring that the number of atoms for each element is the same on both sides of the equation. This is crucial for accurately representing the conservation of mass during a chemical reaction. For the combustion of propane, the balanced equation will provide the ratios of propane, oxygen, carbon dioxide, and water produced, which is necessary for calculating the final amounts of each substance.

Limiting Reactant

The limiting reactant is the substance that is completely consumed first in a chemical reaction, thus determining the maximum amount of product that can be formed. Identifying the limiting reactant is vital for stoichiometric calculations, as it affects the final quantities of all products. In the case of propane combustion, knowing which reactant limits the reaction will help in calculating the exact number of molecules of CO2 and H2O produced.