11. propane (c3hg) is a fuel commonly used in gas grills.
list the steps you would use to calculate the percent carbon in propane by mass.
the first step is started for you. (hint: my explanation required five steps.)
step 1: list what is known and unknown.
known: each mole of propane contains 3 moles c and 8 moles h.
unknown:
step 2:

81.71%

Explanation:

One mole of propane contains 3 moles of carbon atoms and 8 moles of hydrogen atoms, as seen from the molecular formula of . In order to calculate the percent of carbon in propane by mass, we need to remember that %w/w (or percent mass) formula states that:

That is, we need to divide the mass of the component of interest by the total mass of the compound and multiply by 100 to obtain the percentage.

For simplicity, let's take 1 mole of propane and find the mass of 1 mole (hence, we'll be finding the molar mass of propane). To do that, we add the 3 molar masses of carbon and 8 molar masses of hydrogen to obtain a total of:

Now that we have the molar mass of propane, we also need to find the total mass of carbon in 1 mole of propane. We know that we have a total of 3 moles of carbon which corresponds to:

Dividing the mass of carbon present by the total mass of the compound will yield the mass percentage as defined by the formula we introduced:

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.