CA_Lesson_1_Introduction_to_Hydrocarbons.pdf

CHEMISTRY Matter and Change Module 20: Hydrocarbons Lesson 1 Introduction to Hydrocarbons 2 0.1 SECTION Introduction to Hydrocarbons Explain the terms organic compound and organic chemistry. Identify hydrocarbons and the models used to represent them. Distinguish between saturated and unsaturated hy...

CHEMISTRY Matter and Change Module 20: Hydrocarbons Lesson 1 Introduction to Hydrocarbons 2 0.1 SECTION Introduction to Hydrocarbons Explain the terms organic compound and organic chemistry. Identify hydrocarbons and the models used to represent them. Distinguish between saturated and unsaturated hydrocarbons. Describe where hydrocarbons are obtained and how they are separated. microorganism: a tiny organism, such as a bacterium or a protozoan, that cannot be seen without a microscope 2 0.1 SECTION Introduction to Hydrocarbons organic compound unsaturated hydrocarbon hydrocarbon fractional distillation saturated hydrocarbon cracking Hydrocarbons are carbon-containing organic compounds that provide a source of energy and raw materials. 2 0.1 SECTION Introduction to Hydrocarbons Build to the Guiding Questions ❖ What are hydrocarbons and how are they used? 2 0.1 SECTION Introduction to Hydrocarbons Organic Compounds Chemists in the early 19th century knew living things produced a variety of carbon compounds. They called these organic compounds because they were produced by living organisms. Scientists thought that organic compounds came only from living things. Organic Compounds Scientists thought they could not synthesize organic compounds because organisms possessed a vital force needed to make them. Wöhler was the first to produce an organic compound in the lab. A chain of similar experiments followed and the vital force was discredited. Organic Compounds The term organic compound is applied to all carbon-containing compounds with the primary exceptions of carbon oxides, carbides, and carbonates, which are considered inorganic. Organic Compounds Carbon nearly always shares its electrons and forms four covalent bonds. In organic compounds, carbon atoms are bonded to hydrogen atoms or atoms of other elements near carbon in the periodic table—especially nitrogen, oxygen, sulfur, phosphorus, and the halogens. Organic Compounds Carbon atoms also bond to other carbon atoms and form chains from two to thousands of carbon atoms in length. Because carbon forms four bonds, it forms complex, branched-chain structures, ring structures, and even cage-like structures. Hydrocarbons The simplest organic compounds are hydrocarbons. Hydrocarbons contain only the elements carbon and hydrogen. There are thousands of hydrocarbons. The simplest hydrocarbon molecule is methane, CH4. Methane consists of a carbon atom bonded to four hydrogen atoms. Hydrocarbons The figure below shows four different ways to represent a methane molecule. Covalent bonds are represented by a single straight line, which denotes two shared electrons. Hydrocarbons Carbon atoms bond to each other by single, double, and triple bonds. A saturated hydrocarbon contains only single bonds. An unsaturated hydrocarbon contains at least one double or triple bond. 2 0.1 SECTION Introduction to Hydrocarbons CHECK YOUR UNDERSTANDING 1. Explain the difference between saturated and unsaturated hydrocarbons. 2. What is the definition of an organic compound? 3. What are simplest organic compounds? 4. Classify the following as either organic or inorganic compound. CaCO3, CaC2, C2H6, CO2, HCOOH, CCl4 2 0.1 SECTION Introduction to Hydrocarbons Refining Hydrocarbons Many hydrocarbons are obtained from the fossil fuel petroleum. Petroleum formed from the remains of microorganisms that lived in Earth’s oceans millions of years ago. Petroleum is a complex mixture of over a thousand different compounds. To be used, raw petroleum, or crude oil, is separated into simpler components or fractions. Refining Hydrocarbons Separation is carried out by fractional distillation, or fractionation. This process involves boiling the petroleum and collecting components or fractions as they condense at different temperatures. Refining Hydrocarbons 2 0.1 SECTION Introduction to Hydrocarbons Refining Hydrocarbons Fractional distillation towers do not yield fractions in proportion to demand. Heavier fractions are converted to lighter fractions like gasoline by breaking their large molecules into smaller ones. This is called cracking. Cracking is done in the absence of oxygen and in the presence of a catalyst. Cracking also produces starting materials for the synthesis of products like plastics, films, and synthetic fibers. Refining Hydrocarbons Gasoline is not a pure substance. Rather, it is a mixture of hydrocarbons. Most molecules with single covalent bonds in gasoline have 5 to 12 carbon atoms. Gasoline is modified by adjusting its composition to improve performance and reduce pollution, resulting in the octane rating system. 2 0.1 SECTION Introduction to Hydrocarbons PLENARY https://forms.gle/NzbaveZ3P u3sviCN7