Textbook Question
Butane, the fuel used in disposable lighters, has the formula C4H10. The carbon atoms are connected in the sequence C-C-C-C, and each carbon has four covalent bonds. Draw the structural formula of butane.
Ch.23 - Organic and Biological Chemistry
Chapter 23, Problem 4
What is the difference between a straight-chain alkane and a branched-chain alkane?
Verified step by step guidance1
Step 1: Understand the basic structure of alkanes. Alkanes are hydrocarbons with only single bonds between carbon atoms, following the general formula C_nH_{2n+2}.
Step 2: Define a straight-chain alkane. A straight-chain alkane consists of carbon atoms connected in a continuous, unbranched line. Each carbon atom (except the ends) is bonded to two other carbon atoms and enough hydrogen atoms to satisfy the tetravalency of carbon.
Step 3: Define a branched-chain alkane. A branched-chain alkane has a main chain of carbon atoms with one or more carbon atoms branching off from the main chain. These branches are also called alkyl groups.
Step 4: Compare the structures. In a straight-chain alkane, all carbon atoms are connected in a single linear sequence, whereas in a branched-chain alkane, there are one or more side chains or branches attached to the main carbon chain.
Step 5: Consider the implications of branching. Branching can affect the physical properties of alkanes, such as boiling and melting points, due to changes in molecular shape and surface area.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Alkanes
Alkanes are saturated hydrocarbons consisting only of carbon (C) and hydrogen (H) atoms, connected by single bonds. They follow the general formula CnH2n+2, where 'n' is the number of carbon atoms. Alkanes can be classified into straight-chain and branched-chain forms based on the arrangement of their carbon atoms.
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Straight-Chain Alkanes
Straight-chain alkanes, also known as normal alkanes, have a linear structure where carbon atoms are connected in a continuous chain. This arrangement results in a simple, unbranched molecular structure, such as in butane (C4H10), which has four carbon atoms in a row. Their physical properties, such as boiling points, tend to increase with the length of the carbon chain.
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Branched-Chain Alkanes
Branched-chain alkanes contain one or more carbon branches off the main carbon chain, leading to a more complex structure. For example, isobutane (C4H10) is a branched-chain alkane with a three-carbon chain and a single carbon branch. This branching affects the physical and chemical properties of the alkanes, often resulting in lower boiling points compared to their straight-chain counterparts.
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