Question

If a hydrocarbon is combined with enough halogen, all the \(\mathrm{H}\) atoms will eventually be substituted with that halogen atom. Write the balanced chemical reaction between butane and excess bromine.

Short answer

The balanced equation is: \( \text{C}_4\text{H}_{10} + 10\text{Br}_2 \rightarrow \text{C}_4\text{Br}_{10} + 10 \text{HBr} \).

Step-by-step solution

Write the Molecular Formula for Butane

Butane is a hydrocarbon with four carbon atoms, so its molecular formula is \( \text{C}_4\text{H}_{10} \). This gives us a starting point for the reactant side of the equation.

Identify the Required Halogen

According to the problem, we are using bromine as the halogen. The molecular formula for bromine in its diatomic form is \( \text{Br}_2 \).

Predict the Reaction Outcome

When butane reacts with excess bromine, all hydrogen atoms will be replaced by bromine atoms, forming a halogenated hydrocarbon with bromine. This results in the formation of \( \text{C}_4\text{Br}_{10} \).

Write the Unbalanced Chemical Equation

Write the initial reaction without considering stoichiometry: \[ \text{C}_4\text{H}_{10} + \text{Br}_2 \rightarrow \text{C}_4\text{Br}_{10} + \text{HBr} \].

Balance the Chemical Equation

Each \( \text{H} \) atom in butane is replaced with \( \text{Br} \). Start by noting that \( \text{C}_4\text{H}_{10} \) has 10 hydrogen atoms.The balanced chemical equation is:\[ \text{C}_4\text{H}_{10} + 10\text{Br}_2 \rightarrow \text{C}_4\text{Br}_{10} + 10 \text{HBr} \].

Review and Verify

Check the equation to ensure that the number of each type of atom is equal on both sides of the equation. \( 4 \) carbons, \( 10 \) bromines, and \( 10 \) hydrogens are found on each side of the equation.

Key concepts

Halogenation

Halogenation is an essential chemical process in organic chemistry where halogen atoms, like bromine or chlorine, replace hydrogen atoms in a hydrocarbon. This process can significantly alter the properties of the original molecule, making halogenated compounds quite versatile in chemical synthesis.

One of the most interesting aspects of halogenation is its ability to transform hydrocarbons into different kinds of organic compounds. These resulting compounds are often used in industrial applications such as solvents, refrigerants, and in the production of pharmaceuticals.

• Halogenation requires a source of halogens, typically chlorine (\( \text{Cl}_2 \)) or bromine (\( \text{Br}_2 \)).
• These reactions can occur under controlled conditions, like in the presence of ultraviolet light or heat, to facilitate the replacement of hydrogen atoms.
• Halogenation can be radical or electrophilic, depending on the mechanism involved.

Understanding the principles of halogenation provides insight into how complex organic molecules are structurally modified for various applications.

Hydrocarbons

Hydrocarbons are fundamental components of organic chemistry, consisting only of carbon and hydrogen atoms. They serve as a base for forming more complex molecules and include alkanes, alkenes, and alkynes. Each type differs in terms of bond saturation:

• Alkanes are the simplest kind of hydrocarbons, with only single bonds between carbon atoms.
• Alkenes have one or more double bonds, adding reactivity to the molecule.
• Alkynes contain triple bonds and are the most reactive due to high electron density.

For example, butane (\( \text{C}_4\text{H}_{10} \)) is an alkane, characterized by four carbon atoms bonded in a simple chain. This hydrocarbon can undergo halogenation, as seen in many chemical reactions, to produce halogenated hydrocarbons.

Hydrocarbons are the cornerstone of organic compounds and are crucial in fields like energy production, manufacturing, and synthetic chemistry.

Chemical Reactions

Chemical reactions are processes where substances interact, rearranging their atoms to form new compounds. In organic chemistry, these reactions are fundamental for creating diverse molecules necessary for various applications.

For instance, when butane reacts with bromine, a substitution reaction occurs where bromine atoms replace hydrogen atoms, forming \( \text{C}_4\text{Br}_{10} \) and hydrogen bromide (\( \text{HBr} \)). This is a classic example of a halogenation reaction.

• The initial step involves the generation of reactive intermediates or radicals, often requiring external energy like UV light.
• Next, there's a propagation phase, where a chain reaction substitutes each hydrogen atom with a halogen atom.
• Finally, termination occurs, halting further reactions when all reactive sites are occupied or intermediates neutralize each other.

Balancing chemical reactions is crucial to ensure the law of conservation of mass is maintained, meaning atoms on the reactant side match those on the product side.