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An empirical formula is the simplest expression of the relative number of each type of atom in a compound. It provides a straightforward way to depict how the atoms are proportioned but not their actual arrangement.
To find the empirical formula, we start by identifying the percentage composition of each element within a compound. In our case, the hydrocarbon consists solely of carbon and hydrogen.

• Carbon is 85.63% of the total mass.
• Hydrogen is calculated as 100% - 85.63% = 14.37%.

The next step involves converting these percentages into a mole ratio by dividing each by their respective molar masses. This calculation gives a ratio of carbon to hydrogen, which simplifies to a 1:2 relationship. Therefore, the empirical formula is denoted as \(C_nH_{2n}\).

Hydrocarbons are organic compounds made exclusively of carbon (C) and hydrogen (H) atoms. They serve as a fundamental category in organic chemistry, acting as the foundation for more complex chemical structures. Hydrocarbons can be simple, like methane, owing their relevance due to their role in fuel production and numerous industrial applications.
In this problem, we focus on the hydrocarbon type that forms the basis of the compound 2-butene. This particular hydrocarbon has a molecular formula of \(C_4H_8\), indicating four carbon atoms are bonded to eight hydrogen atoms. 2-butene is an example of an alkene, which is characterized by the presence of at least one carbon-carbon double bond.

The molecular structure illustrates how atoms are arranged in a compound, dictating its chemical properties and reactivity. Molecular structures can be illustrated via structural formulas, which show the connectivity between atoms.
For 2-butene, the structural formula can be simplified as \(CH_3-CH=CH-CH_3\). This molecular formula identifies it as a symmetric alkene, implying the existence of a carbon double bond featuring between its second and third carbon atoms. The presence of this double bond classifies it as a secondary alcohol precursor due to its reaction pattern with water to form alcohols upon hydration.

Chemical reactions are processes where substances (reactants) are transformed into new substances (products), involving the rearrangement of atoms. In the realm of organic chemistry, understanding reactions is essential as they reveal insights into how compounds interact.
In the exercise, the hydrocarbon, 2-butene, undergoes a reaction with water to predominantly yield a secondary alcohol. This reaction aligns with the hydration of alkenes—an organic chemistry essential.

• The reaction predominantly leads to a secondary alcohol due to Markovnikov’s rule, which favors the addition of the water's OH group to the more substituted carbon atom.
• The minor product, a primary alcohol, results from the less common anti-Markovnikov addition pathway.

These chemical interactions depict the versatility of hydrocarbons like 2-butene and highlight the importance of structural forms in chemical reactions.