--- title: "n-Butane in Intro to Chemistry" description: "n-Butane is a straight-chain alkane, C4H10, used in Intro to Chemistry to study hydrocarbons, isomerism, boiling point, and fuel behavior." canonical: "https://fiveable.me/intro-chem/key-terms/n-butane" type: "key-term" subject: "Intro to Chemistry" unit: "Unit 20" --- # n-Butane in Intro to Chemistry ## Definition n-Butane is the straight-chain alkane with formula C4H10. In Intro to Chemistry, it shows how hydrocarbon structure affects boiling point, physical state, and isomerism. ## What It Is n-Butane is the straight-chain version of butane in Intro to Chemistry, a saturated hydrocarbon with the formula C4H10. “Straight-chain” means the four carbon atoms are connected in one continuous line, with only single carbon-carbon bonds and enough hydrogen atoms to fill the remaining valences. Because it is an alkane, n-butane has no double or triple bonds. That makes it one of the simplest examples of a hydrocarbon that is fully saturated. You can think of it as a basic carbon skeleton that follows the alkane pattern, where each carbon forms four total bonds and the molecule contains the maximum number of hydrogens for that carbon count. n-Butane is a good example of how structure changes properties without changing the molecular formula. It has the same formula as isobutane, but the atoms are arranged differently. That branching difference changes how the molecules pack together, which changes intermolecular forces and boiling point. For n-butane, the boiling point is about -0.5°C at standard atmospheric pressure, so it is a gas at room temperature. In chemistry class, n-butane often appears in hydrocarbon naming, structure comparison, and property questions. You may see it in a table of alkanes next to methane, ethane, propane, and pentane, or in a question asking you to identify whether a molecule is straight-chain or branched. The “n” stands for normal, which is an older naming convention used to show the unbranched form. It also shows up as a real-world fuel. Lighters and camping stoves often use butane because it burns easily and stores as a liquid under pressure. That connection makes n-butane useful for seeing how a molecule can be a gas at room temperature but still be practical as a fuel in a pressurized container. ## Why It Matters n-Butane is one of the cleanest examples of how Intro to Chemistry connects structure to properties. Once you know it is a straight-chain alkane, you can explain why it behaves differently from a branched isomer even though both molecules have the same formula. That shows up in three common chemistry ideas. First, hydrocarbon naming depends on recognizing the carbon chain. Second, boiling point depends on intermolecular attraction and molecular shape, not just the formula. Third, fuel behavior depends on whether a substance is a gas, a liquid, or a pressurized liquid under room conditions. It also gives you a concrete molecule to compare with the rest of the alkane family. If you can place n-butane between propane and pentane, or compare it to isobutane, you are already using the core logic of organic chemistry: count carbons, identify the bonding pattern, then predict the property trend. That same habit carries over to later topics like isomers, hydrocarbons, and reactions. ## Connections ### Alkane n-Butane is an alkane, so it fits the saturated hydrocarbon pattern of single carbon-carbon bonds and the formula trend for open-chain hydrocarbons. If you can recognize butane as an alkane, you can also predict that it is relatively nonpolar, burns readily, and belongs in the simple hydrocarbon family rather than in the unsaturated groups. ### Isomer n-Butane and isobutane are isomers because they have the same molecular formula, C4H10, but different atom arrangements. That difference is the whole point of the comparison in Intro to Chemistry: same formula does not always mean same shape or same boiling point. This is one of the easiest places to see structure-property relationships. ### Boiling Point n-Butane’s boiling point is low because small hydrocarbons have weak intermolecular forces. When you compare n-butane to a branched isomer, you can see how shape affects how well molecules pack together and how easily they enter the gas phase. That makes boiling point a useful clue in property questions. ### [carbon-carbon bonds](/intro-chem/key-terms/carbon-carbon-bonds) The carbon-carbon bonds in n-butane are all single bonds, which makes the molecule flexible and fully saturated. Those single bonds build the chain structure that defines the molecule, and they are what you count when you draw a Lewis structure or line-angle formula. The bonding pattern also tells you why n-butane is an alkane. ## On the AP Exam A quiz question might show two C4H10 structures and ask you to identify which one is n-butane. You would look for the straight chain, not the branched version. In a problem set, you may also use n-butane to predict whether a molecule is gas or liquid at room temperature, or to explain why branching changes boiling point. If your teacher gives you a structure, you should be ready to name it, classify it as an alkane, and compare it with a structural isomer. If the question asks about physical properties, connect the small nonpolar hydrocarbon structure to its low boiling point and easy vaporization. That is the main move: read the structure, then explain the property from the structure. ## n-Butane vs isobutane n-Butane and isobutane share the formula C4H10, so they are easy to mix up. The difference is shape: n-butane is straight-chain, while isobutane is branched. In chemistry, that branching changes how the molecules interact and gives them different boiling points. ## Key Takeaways - n-Butane is the straight-chain alkane with formula C4H10. - It is a saturated hydrocarbon, so all of its carbon-carbon bonds are single bonds. - n-Butane and isobutane have the same formula but different structures, which makes them isomers. - Its low boiling point helps explain why it is a gas at room temperature but can still be stored as a pressurized fuel. - In Intro to Chemistry, n-butane is a useful example for naming hydrocarbons, comparing structures, and predicting physical properties. ## FAQs ### What is n-Butane in Intro to Chemistry? n-Butane is the straight-chain form of butane, a saturated hydrocarbon with the formula C4H10. In Intro to Chemistry, it is used to show how carbon chain shape affects naming, boiling point, and whether a molecule is an isomer of another hydrocarbon. ### Is n-Butane the same as isobutane? No. They both have the formula C4H10, but n-butane is straight-chain and isobutane is branched. That difference in structure changes their physical properties, especially boiling point. ### Why does n-Butane have such a low boiling point? n-Butane is a small, nonpolar hydrocarbon, so its intermolecular forces are weak. Because the molecules do not attract each other strongly, they separate into the gas phase at a low temperature. ### Where do you see n-Butane in chemistry class? You usually see it in hydrocarbon sections, molecule drawings, naming questions, and property comparisons with other alkanes. It also shows up in examples of fuels, refrigerants, and structural isomerism. ## Related Study Guides - [20.1 Hydrocarbons](/intro-chem/unit-20/1-hydrocarbons/study-guide/qhCc8xCQkKCIVati) ## About This Document Canonical Fiveable pages are available as Markdown at the same path plus `.md`. - [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns - [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing - [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`) - [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`) ## Structured Data ```json {"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/intro-chem/key-terms/n-butane#resource","name":"n-Butane in Intro to Chemistry","url":"https://fiveable.me/intro-chem/key-terms/n-butane","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/intro-chem/key-terms/n-butane#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-07-03T02:22:18.202Z","isPartOf":{"@type":"Collection","name":"Intro to Chemistry Key Terms","url":"https://fiveable.me/intro-chem/key-terms"},"author":{"@type":"Organization","@id":"https://fiveable.me/editorial#content-team","name":"Fiveable Content Team","url":"https://fiveable.me/editorial","parentOrganization":{"@id":"https://fiveable.me/#organization"},"member":[{"@type":"Person","name":"Amanda DoAmaral","sameAs":["https://www.linkedin.com/in/adoamaral"]},{"@type":"Person","name":"Becky Bahr","sameAs":["https://www.linkedin.com/in/becky-bahr-b52743132"]}]},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/intro-chem/key-terms/n-butane#term","name":"n-Butane","description":"n-Butane is the straight-chain alkane with formula C4H10. 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