Propane is a form of hydrocarbon that has to be burnt while oxygen is present in the air. Now the reaction will undergo the process of combustion which will result in carbon dioxide and water but all have to come in gas phase.
In this entire process, propane has to go through the combustion reaction. Before we move further into the equation and the reaction that takes place, we need to understand what combustion reaction is. It is a major series of chemical reaction that can also be referred to as burning in simple language. It occurs especially when hydrocarbon comes in contact with oxygen that is present in the air. They mix up and react with each other resulting in carbon dioxide and water. It does not necessarily have to produce fire at the end of the reaction but if fire comes out as a consequence of the reaction, it is an indicator or can be called a characteristic of the reaction. Now in this particular reaction, since propane has to undergo the procedure as mentioned above it can be understood that it acts like any other alkanes. The way any other alkanes would have reacted in coming contact with oxygen the same happens here in this reaction. While oxygen is present in the air, propane starts burning in the presence of oxygen that results in water and carbon dioxide as well. There is an exception to the reaction because the amount of oxygen in the air is not always the same. When the amount of oxygen is not enough to produce carbon dioxide through the reaction, it produces carbon monoxide by burning the propane instead.
The general equation that denotes the process of hydrocarbon going through the reaction of combustion is
CxHy (g) + (x +y/4) O2 xCO2 (g) +y/2H2O (g)
Since we are about to study the process of combustion of propane, we have to replace the value of x and y with 3 and 8, therefore,
x= 3 while y= 8
The molecular formula propane has is of C3H8, hence, after balancing the equation it will look like
C3H8 (g) + (3+ 8/4) O 2 3CO2 (g) + 8/2H2O (g)
Or it can be written in a more precise way that is,
C3H8 (g) + (3+ 2) O2 3CO2 (g) + 4H2O (g)
C3H8 (g) + 5O2 = 3CO2 (g) + 4H2O (g)
In the above mentioned equation it is visible that propane reacts with 5 molecules of oxygen that produces 3 molecules of carbon dioxide and 4 molecules of water. We have to remember that all the products that are formed through the reaction come out in gas phase.