Introduction to organic chemistry
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Intros
Examples
Lessons
- Recall the different ways to represent organic compounds.
Which types of formulae show chains of carbon atoms in organic molecules?
i) Molecular formula
ii) Condensed formula
iii) Skeletal formula
iv) Structural formula
- Discuss the uses and benefits of using different chemical formulae methods.
Codeine is a drug used to treat headaches and other forms of pain. It has a molecular formula of CHNO.
- Give a reason why it would not be useful to represent codeine using empirical formula.
- Give a reason why using structural formula is more appropriate than molecular formula for representing codeine.
- Give a reason why using skeletal formula is often used instead of structural formula for large compounds.
Topic Notes
Introduction to Organic Chemistry
Organic chemistry is the fascinating study of carbon-containing compounds, forming the backbone of life itself. This branch of chemistry explores the structure, properties, and reactions of molecules that make up living organisms and countless everyday materials. Our introduction video provides a captivating overview of organic chemistry, helping viewers grasp its fundamental concepts and significance. As we delve into this field, you'll discover how carbon's unique bonding capabilities lead to an astounding variety of compounds, from simple hydrocarbons to complex biomolecules. The video teases exciting topics to be covered in the main sections, including functional groups, reaction mechanisms, and the synthesis of important organic molecules. By understanding organic chemistry, we gain invaluable insights into the chemistry of life, paving the way for advancements in medicine, materials science, and environmental studies. Join us on this journey to unravel the mysteries of carbon compounds and their pivotal role in shaping our world.
The Origins and Scope of Organic Chemistry
Organic chemistry, a fundamental branch of chemical science, has its roots deeply embedded in the study of compounds derived from living organisms. This historical context provides a fascinating journey through scientific understanding and discovery. In the early days of chemistry, scientists believed in a concept called vitalism, which proposed that organic compounds could only be produced by living organisms due to a special "vital force." This theory drew a sharp distinction between organic and inorganic matter, suggesting that organic compounds possessed unique properties that could not be replicated in a laboratory setting.
However, the concept of vitalism was dramatically challenged and ultimately disproven in 1828 when Friedrich Wöhler accidentally synthesized urea, an organic compound, from inorganic materials. This groundbreaking discovery opened the floodgates for the field of organic chemistry, demonstrating that organic compounds could indeed be created artificially, without the need for a "vital force." This revelation marked a pivotal moment in the history of chemistry, blurring the lines between organic and inorganic matter and paving the way for the modern understanding of organic chemistry.
At the heart of organic chemistry lies the element carbon, which plays a central and indispensable role in forming organic compounds. Carbon's unique ability to form diverse molecules stems from its electronic configuration, allowing it to form up to four stable covalent bonds. This property enables carbon to create an astounding variety of compounds, from simple molecules to complex macromolecules, forming the basis of life itself. The versatility of carbon in forming different types of bonds and structures is unparalleled in the periodic table, making it the backbone of organic chemistry.
The importance of organic compounds in living systems cannot be overstated. Amino acids, for instance, are the building blocks of proteins, essential for countless biological functions. These organic molecules contain both amino and carboxyl groups, allowing them to link together in long chains to form proteins. Nucleotides, another crucial class of organic compounds, are the structural units of nucleic acids like DNA and RNA, which store and transmit genetic information. Glucose, a simple sugar, serves as a primary energy source for many organisms, highlighting the diverse roles organic compounds play in sustaining life.
The chemical bonds formed by carbon atoms are key to understanding the structure and function of organic molecules. Carbon can form single, double, and triple covalent bonds, leading to a vast array of molecular shapes and properties. These bonds can be between carbon atoms or between carbon and other elements, most commonly hydrogen, oxygen, nitrogen, and sulfur. The ability of carbon to form long chains, branched structures, and rings further contributes to the complexity and diversity of organic compounds. This versatility allows for the creation of molecules with specific functions, from the lipids that form cell membranes to the complex enzymes that catalyze biochemical reactions.
As our understanding of organic chemistry has evolved, so too has our ability to synthesize and manipulate organic compounds. This knowledge has led to countless applications in medicine, materials science, and technology. From the development of life-saving drugs to the creation of new materials with extraordinary properties, organic chemistry continues to shape our world in profound ways. The field remains at the forefront of scientific research, constantly pushing the boundaries of what's possible in molecular design and synthesis, and promising exciting discoveries for years to come.
Naming and Representing Organic Compounds
Organic chemistry, the study of carbon-containing compounds, relies heavily on a systematic approach in organic chemistry to naming molecules. This system, known as nomenclature, is crucial for clear communication among chemists worldwide. Let's delve into the basics of naming organic compounds, starting with alkanes, and explore various ways to represent these molecules.
The naming of organic compounds begins with identifying the carbon chain length and any functional groups present. Alkanes, the simplest organic compounds consisting of only carbon and hydrogen atoms with single bonds, serve as an excellent starting point. The naming of alkanes follows a straightforward pattern based on the number of carbon atoms in the longest chain:
- Methane (CH): 1 carbon atom
- Ethane (CH): 2 carbon atoms
- Propane (CH): 3 carbon atoms
- Butane (CH): 4 carbon atoms
As the carbon chain lengthens, the names continue with pentane (5), hexane (6), heptane (7), and so on. This systematic approach in organic chemistry allows chemists to quickly understand the basic structure of a compound from its name.
When it comes to representing organic compounds, several methods are available, each with its own advantages and limitations:
- Molecular Formula: This representation shows the types and numbers of atoms in a molecule. For example, the molecular formula for propane is CH. While concise, it doesn't provide information about the structure or arrangement of atoms.
- Empirical Formula: This shows the simplest whole-number ratio of atoms in a compound. For propane, the empirical formula is the same as its molecular formula (CH). However, for more complex molecules like glucose (CHO), the empirical formula would be CHO.
- Condensed Formula: This representation shows the arrangement of atoms without drawing out all bonds. For propane, it would be CHCHCH. This method provides more structural information than the molecular formula while remaining relatively compact.
- Structural Formula: This is the most detailed representation, showing all atoms and bonds in a molecule. For propane, it would be drawn as HC-CH-CH, clearly illustrating the carbon backbone and hydrogen placement.
Each representation method serves different purposes. Molecular and empirical formulas are useful for quick identification and calculations. The condensed formula offers a balance between simplicity and structural information. The structural formula provides the most comprehensive view of a molecule's arrangement, essential for understanding reactivity and properties.
As organic compounds become more complex, with branched chains, multiple bonds, and various functional groups, the nomenclature system expands to accommodate these features. Prefixes and suffixes are added to indicate the presence of double bonds (alkenes), triple bonds (alkynes), and functional groups like alcohols (-ol), aldehydes (-al), and carboxylic acids (-oic acid).
Understanding and applying this systematic approach in organic chemistry to naming and representing organic compounds is fundamental in organic chemistry. It enables chemists to communicate complex molecular structures efficiently, predict chemical properties, and plan synthetic routes. As students progress in their study of organic chemistry, mastering naming organic compounds and representation methods becomes increasingly important for tackling more advanced concepts and reactions.
Skeletal Formula: A Simplified Representation
In organic chemistry, the skeletal formula is an efficient and widely used method for representing the structure of organic compounds. This simplified notation focuses on the carbon backbone of molecules, providing a clear and concise visual representation that is both easy to draw and interpret. The skeletal formula, also known as a line-angle formula, offers a streamlined approach to depicting complex organic structures without the clutter of explicitly shown atoms and bonds.
The key principle behind skeletal formulas is the representation of carbon atoms as the vertices and endpoints of a zigzag chain. This zigzag pattern effectively illustrates the tetrahedral arrangement of carbon atoms in organic molecules. One of the most important rules in drawing skeletal formulas is that carbon atoms are not explicitly labeled. Instead, they are implied at each joint and end of the zigzag chain. This simplification greatly reduces the visual complexity of the formula, especially for larger molecules.
Another crucial aspect of skeletal formulas is the treatment of hydrogen atoms. In this notation, hydrogen atoms bonded to carbon are not shown explicitly. Instead, they are implied based on the understanding that carbon atoms in organic compounds typically form four bonds. The number of implied hydrogen atoms can be easily calculated by subtracting the number of visible bonds from four for each carbon atom. This rule of implicit hydrogens significantly contributes to the formula's simplicity and readability.
To illustrate the process of converting a structural formula to a skeletal formula, let's consider the example of butane (C4H10). In its structural formula, butane is represented with all carbon and hydrogen atoms explicitly shown. To convert this to a skeletal formula, we first draw a zigzag line representing the four carbon atoms. The hydrogen atoms are then omitted, resulting in a simple zigzag line that represents the carbon backbone of butane. Similarly, for a more complex molecule like hexane (C6H14), the skeletal formula would be a longer zigzag line with six vertices, each representing a carbon atom.
The advantages of using skeletal formulas in organic chemistry are numerous. Firstly, they offer a significant time-saving benefit, as complex molecules can be quickly sketched without the need to draw every atom and bond. This is particularly useful in rapid note-taking during lectures or when brainstorming synthetic pathways. Secondly, skeletal formulas provide a clearer view of the overall molecular structure, making it easier to identify functional groups and structural features that are crucial in understanding chemical properties and reactivity.
Moreover, skeletal formulas are especially valuable when dealing with large, complex organic molecules such as pharmaceuticals or natural products. In these cases, the simplified representation allows chemists to focus on the essential structural elements without being distracted by the multitude of carbon and hydrogen atoms. This clarity is invaluable in fields like medicinal chemistry and biochemistry, where understanding the relationship between molecular structure and biological activity is paramount.
In conclusion, the skeletal formula stands as a cornerstone in the visual language of organic chemistry. Its ability to convey complex molecular structures through a simple zigzag chain, with implicit carbon and hydrogen atoms, makes it an indispensable tool for chemists. By mastering the rules and conventions of skeletal formulas, students and professionals alike can efficiently communicate and analyze organic structures, facilitating deeper understanding and more effective problem-solving in the field of organic chemistry.
Functional Groups in Organic Chemistry
Functional groups are specific atoms or combinations of atoms within organic molecules that are responsible for the characteristic chemical properties and reactivity of those compounds. These groups play a crucial role in determining how organic molecules interact with other substances and behave in various chemical reactions. Understanding functional groups is essential for predicting and explaining the behavior of organic compounds in different environments.
Common functional groups include alkenes, alkynes, and alcohols, among others. Alkenes are characterized by a carbon-carbon double bond, while alkynes feature a carbon-carbon triple bond. Alcohols contain a hydroxyl group (-OH) attached to a carbon atom. These functional groups impart distinct properties to the molecules they are part of, influencing factors such as solubility, boiling point, and chemical reactivity.
Functional groups are represented in various ways in chemical formulas. In structural formulas, they are shown explicitly, while in condensed formulas, they may be abbreviated. Skeletal formulas, which are commonly used in organic chemistry, represent the carbon backbone of a molecule as a series of lines, with functional groups indicated at the appropriate positions. For example, an alkene might be represented by a double line between two carbon atoms, while an alcohol group would be shown as an "OH" at the end of a line.
The presence of specific functional groups allows chemists to categorize organic compounds into families with similar chemical properties. For instance, all alcohols share certain characteristics due to their hydroxyl group, such as the ability to form hydrogen bonds. This categorization helps in predicting how different compounds will behave in chemical reactions and in understanding their physical properties.
Changing a functional group can dramatically alter a compound's behavior. For example, converting an alcohol to an aldehyde by oxidizing the hydroxyl group changes the compound's reactivity, solubility, and even its smell. Ethanol, a common alcohol, is soluble in water and has a relatively low boiling point. However, if we oxidize it to form acetaldehyde, we get a compound with different solubility properties and a much lower boiling point.
The importance of functional groups extends beyond basic chemistry into biochemistry and pharmaceutical science. Many drugs are designed by modifying functional groups on existing molecules to enhance their effectiveness or reduce side effects. In biochemistry, the functions of enzymes and other biomolecules are often determined by the presence and arrangement of specific functional groups.
Understanding functional groups also aids in the synthesis of new compounds. Chemists can plan reactions that target specific functional groups to build complex molecules step by step. This approach is fundamental in the development of new materials, pharmaceuticals, and other chemical products.
In conclusion, functional groups are the key to understanding the vast diversity of organic compounds. They determine how molecules interact, react, and behave in various environments. By recognizing and understanding these groups, chemists can predict properties, plan syntheses, and develop new compounds with desired characteristics. The study of functional groups forms the foundation of organic chemistry and continues to be crucial in advancing our understanding of chemical processes in both laboratory and biological settings.
Applications of Organic Chemistry in Modern Life
Organic chemistry plays a pivotal role in numerous aspects of our daily lives, with its applications spanning across various industries and scientific fields. One of the most significant areas where organic chemistry has a profound impact is the petrochemical industry. Petrochemicals, derived from petroleum and natural gas, form the backbone of many products we use every day. The industry produces a wide range of materials, including fuels like gasoline and diesel, as well as plastics, synthetic fibers, and rubber. These products are essential in transportation, packaging, and manufacturing sectors.
In the realm of plastics, organic chemistry has enabled the development of versatile materials such as polyethylene, polypropylene, and polyvinyl chloride (PVC). These materials have revolutionized packaging, construction, and consumer goods industries. For instance, high-density polyethylene (HDPE) is used in milk jugs and shampoo bottles, while PVC is commonly found in pipes and window frames.
The pharmaceutical industry heavily relies on organic chemistry for drug discovery and development. Many life-saving medications are organic compounds synthesized through complex chemical processes. For example, aspirin (acetylsalicylic acid) is a simple organic molecule that has been used for pain relief for over a century. More complex drugs like penicillin, an antibiotic with a β-lactam ring structure, have saved countless lives since their discovery. Understanding the organic structures of these compounds allows scientists to modify and improve their efficacy and reduce side effects.
In materials science, organic chemistry contributes to the development of advanced materials with unique properties. Conductive polymers, such as polyaniline and polypyrrole, have applications in electronic devices and sensors. Organic light-emitting diodes (OLEDs) utilize organic compounds to create efficient, flexible displays found in smartphones and televisions. These innovations demonstrate how organic chemistry bridges the gap between traditional chemistry and cutting-edge technology.
Food chemistry is another field where organic chemistry plays a crucial role. It helps in understanding the composition of food, developing new flavors and preservatives, and improving food safety. For instance, the Maillard reaction, a complex series of chemical reactions between amino acids and reducing sugars, is responsible for the browning and flavor development in cooked foods. This knowledge allows food scientists to enhance taste and texture in processed foods.
Environmental science also benefits from organic chemistry. It aids in understanding the behavior of pollutants in ecosystems and developing methods for their detection and remediation. For example, organic chemists study the degradation of pesticides in soil and water, helping to assess their environmental impact and design more eco-friendly alternatives. Additionally, organic chemistry contributes to the development of biodegradable materials and green chemistry practices that reduce environmental harm.
The applications of organic chemistry extend to personal care products, textiles, and agriculture as well. From the fragrances in perfumes to the dyes in clothing and the pesticides used in farming, organic compounds are ubiquitous in our daily lives. By understanding the principles of organic chemistry, scientists continue to innovate and improve products that enhance our quality of life while striving for sustainability and environmental responsibility.
Conclusion
In this introduction to organic chemistry, we've covered essential concepts that form the foundation of this vital field. We explored the unique properties of carbon, the importance of molecular structure, and the basics of nomenclature. Understanding organic chemistry is crucial for students pursuing chemistry, biology, and related sciences, as it underpins many biological processes and industrial applications. This introduction provides a solid starting point, but there's much more to discover. We encourage you to delve deeper into fascinating topics like reaction mechanisms and organic synthesis. These areas will further enhance your understanding and appreciation of organic reaction mechanisms's complexity and beauty. Remember, the concepts covered in this introductory video are fundamental to your journey in organic chemistry. By mastering these basics, you'll be well-equipped to tackle more advanced topics and applications in the field. Continue exploring, and you'll uncover the incredible world of organic molecules that shape our lives and the world around us.
Organic Chemistry - Introduction
Organic chemistry - Introduction
Beginning of organic chemistry.
Step 1: Understanding the Scope of Organic Chemistry
Organic chemistry is a branch of chemistry that focuses on the study of carbon-containing compounds. This lesson serves as an introduction to the field, exploring its origins, evolution, and fundamental concepts. Initially, organic chemistry was thought to be distinct from inorganic chemistry due to the belief that organic compounds contained a "vital force" derived from living organisms. This idea, known as vitalism, has since been debunked, but it played a crucial role in the early development of the field.
Step 2: Historical Background of Organic Chemistry
The term "organic" is derived from the word "organism," reflecting the early belief that organic compounds were exclusively derived from living entities such as plants, animals, and trees. Early chemists observed that these compounds exhibited unique properties that set them apart from inorganic substances like salts and minerals. This led to the initial classification of chemicals into organic and inorganic categories.
Step 3: The Role of Carbon in Organic Chemistry
Central to the study of organic chemistry is the carbon atom, a versatile element capable of forming a wide variety of compounds. Carbon's ability to form stable bonds with other elements, including itself, allows for the creation of complex molecules essential for life. This property is fundamental to the structure and function of organic compounds.
Step 4: Key Organic Compounds in Biological Systems
Organic chemistry is integral to understanding biological processes. Some of the most important organic compounds in living organisms include amino acids, nucleotides, and glucose. Amino acids link together to form proteins, which are crucial for various cellular functions. Nucleotides form long chains to create DNA, the molecule responsible for genetic information. Glucose, in combination with oxygen, undergoes metabolic reactions to produce energy necessary for sustaining life.
Step 5: The Importance of Carbon Compounds
Carbon compounds are often referred to as the "building blocks of life" due to their essential role in biological systems. The unique ability of carbon to form long chains and complex structures underpins the diversity of organic molecules. This characteristic is vital for the formation of macromolecules like proteins, nucleic acids, and carbohydrates, which are essential for life processes.
Step 6: Representing Organic Molecules
In organic chemistry, it is crucial to be able to represent molecules in various ways. This includes drawing structural formulas, using molecular models, and understanding different representations such as Lewis structures and skeletal formulas. These tools help chemists visualize and communicate the structure and function of organic compounds effectively.
Step 7: Conclusion and Further Exploration
By the end of this introductory lesson, you should have a foundational understanding of what organic chemistry entails, its historical context, and the significance of carbon in forming organic compounds. This knowledge sets the stage for further exploration into more complex topics within the field, such as reaction mechanisms, synthesis, and the role of organic chemistry in various industries.
FAQs
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What is organic chemistry?
Organic chemistry is the study of compounds containing carbon. It focuses on the structure, properties, composition, reactions, and synthesis of organic compounds, which form the basis of life and many materials we use daily.
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Why is carbon so important in organic chemistry?
Carbon is central to organic chemistry due to its unique ability to form up to four stable covalent bonds. This property allows carbon to create an incredibly diverse range of compounds, from simple molecules to complex macromolecules, forming the backbone of life itself.
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What are functional groups in organic chemistry?
Functional groups are specific atoms or combinations of atoms within organic molecules that are responsible for the characteristic chemical properties and reactivity of those compounds. Examples include alcohols (-OH), aldehydes (-CHO), and carboxylic acids (-COOH).
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How are organic compounds named?
Organic compounds are named using a systematic approach called nomenclature. This system is based on the number of carbon atoms, the type of bonds between them, and the presence of functional groups. For example, simple alkanes are named with prefixes like meth- (1 carbon), eth- (2 carbons), prop- (3 carbons), etc.
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What are some real-world applications of organic chemistry?
Organic chemistry has numerous applications in everyday life, including pharmaceuticals (drug design and synthesis), materials science (plastics, synthetic fibers), food chemistry (flavors, preservatives), petrochemicals (fuels, lubricants), and environmental science (pollutant analysis, green chemistry).
Prerequisite Topics for Introduction to Organic Chemistry
Embarking on the journey of organic chemistry requires a solid foundation in several key areas. Understanding these prerequisite topics is crucial for grasping the complexities of organic compounds and their reactions. One of the most fundamental concepts is the structure and bonding of carbon. This topic forms the backbone of organic chemistry, as carbon's unique bonding properties allow for the formation of diverse organic molecules.
Carbon's ability to form stable covalent bonds with itself and other elements is what makes organic chemistry so rich and varied. By mastering the principles of carbon bonding, students can better understand the formation of complex organic structures, from simple hydrocarbons to intricate biomolecules. This knowledge is essential for predicting molecular shapes, reactivity, and properties of organic compounds.
Another critical skill in organic chemistry is understanding reaction mechanisms in organic chemistry, often represented through arrow pushing or curly arrow notation. This technique is indispensable for visualizing how electrons move during chemical reactions. By learning to use and interpret these arrows, students can predict reaction outcomes, understand why certain reactions occur, and even design new synthetic pathways.
Proficiency in arrow pushing allows for a deeper comprehension of how organic molecules interact and transform. It's a powerful tool that bridges the gap between the static representation of molecules and the dynamic nature of chemical reactions. This skill is particularly valuable when studying complex organic synthesis and biochemical processes.
Equally important is the ability to correctly identify and name organic compounds. Naming organic compounds is not just about memorization; it's a systematic approach that provides crucial information about a molecule's structure and properties. Understanding nomenclature allows chemists to communicate effectively and unambiguously about complex organic structures.
Mastering organic nomenclature enables students to quickly deduce structural information from a compound's name and vice versa. This skill is essential for interpreting scientific literature, writing accurate lab reports, and engaging in meaningful discussions about organic chemistry concepts.
By thoroughly grasping these prerequisite topics - carbon bonding, reaction mechanisms, and organic nomenclature - students lay a strong foundation for their study of organic chemistry. These concepts are interconnected and build upon each other, creating a comprehensive understanding of how organic molecules behave and interact. As students progress in their organic chemistry studies, they'll find that these fundamental principles continually resurface, reinforcing their importance and providing a framework for tackling more advanced topics.
In conclusion, investing time in mastering these prerequisite topics will significantly enhance a student's ability to navigate the fascinating world of organic chemistry. It's not just about memorizing facts; it's about developing a intuitive understanding of the principles that govern the behavior of organic compounds. With this solid grounding, students will be well-prepared to explore the diverse and exciting field of organic chemistry, from synthetic applications to understanding the chemistry of life itself.
- How organic chemistry began and how it got its name.
- The reason that carbon's chemistry is studied much more than the chemistry of other elements.
- The basic rules of naming simple organic compounds.
- The different ways to draw and represent organic compounds and their features.
Notes:
- Organic chemistry is all about carbon compounds. Any compound that contains carbon atoms can be called an organic compound, but it usually means compounds with a carbon chain of some type.
The earliest organic chemistry started with chemicals found from living organisms like trees, other plants and animals.
Some of the most important molecules in living organisms are carbon compounds:- Amino acids that combine to make the proteins in our body.
- Nucleotides that combine to make the DNA in our cells.
- Glucose that breaks down in respiration, producing the energy for all living processes
- Carbon atoms can make four separate bonds with any other atom(s), including other carbon atoms. This allows for an incredible variety of bonding to different atoms in compounds of different sizes. Thats why there are millions of carbon compounds and organic chemistry is such a large field.
- Since there are so many different carbon compounds, chemists organize compounds by their functional group, the most reactive part or group of atoms in the molecule. We will learn specific functional groups in the next few lessons.
- Because carbon can bond to itself in these long chains, these functional group families of carbon compounds are normally then arranged in a homologous series. A homologous series is a family of compounds with the same functional group and general formula that differs from the next by -CH2-, which is a unit of a carbon chain.
- Aside from living organisms, organic molecules have a wide range of uses in our day to day lives, with most being products of crude oil and the petroleum industry. Some organic chemicals from crude oil are:
- Gasoline/petrol, fuel for cars.
- Kerosene, fuel for aircraft.
- Refinery gases used as fuels, heating homes.
- Bitumen, used to tar roads.
- 'Naphtha' which is a mix of organic compounds that are used to make many different chemicals like plastics and cosmetics.
- Atorvastatin, heart disease medication.
- Humira, a medication for many autoimmune (the body attacking itself) diseases.
- Prozac, an antidepressant.
- Salbutamol, anti-asthma medication.
- There are so many organic compounds that they are divided into categories depending on what atoms or types of bonds they contain. Amongst the simplest and most important, compounds containing only carbon and hydrogen are called hydrocarbons.
- There is a systematic way of naming organic compounds. The two most important, basic rules are below:
- Identify the longest carbon chain in the compound. This is the core of the compound name. Depending on the carbon chain length, the following names are assigned. The table below summarizes them.
- Identify the functional group(s) in the compound. This will give you the suffix (end part) of the name. A few basic examples (which we'll study in detail later) are in the table below.
- Combining these two parts will give you the name of unbranched organic compounds:
- e.g. hexane (6 carbon chain, alkane),
- butene (4 carbon chain, alkene),
- ethyne (2 carbon chain, alkyne).
- Ethanol (2-carbon alkane chain, alcohol).
- When studying organic compounds, there are many ways to represent a chemical compound that we are talking about. Some are simpler than others, and some are more appropriate in certain situations.
- We already know the molecular formula, which shows the chemical symbols of the atoms in the molecule and how many of these atoms there are.
- For example CH4 is a compound which has one carbon atom (symbol C) and four hydrogen atoms (symbol H) in each molecule.
- The empirical formula is a shortened version of the molecular formula which shows the smallest whole-number ratio of the molecular formula.
- For C2H6, the empirical formula would be CH3.
- The molecular formula C4H10 has the empirical formula C2H5. It cannot be CH2.5 because there is a non-integer number of atoms (you cant have half an atom in a molecule!)
- For organic compounds we can also use the condensed formula – this is used to show the chain of carbon atoms in the compound.
- For example C5H12 can be written as CH3-CH2-CH2-CH2-CH3 to show the 5 carbon chain in the molecule.
- You could also use the structural/displayed formula, which shows all the bonds between all atoms in the molecule.
- For larger organic molecules, the structural formula can be simplified by using skeletal formula to save time while keeping all the relevant information. The skeletal formula shows carbon chains as zig-zags, where the carbon atoms are the joints in the chain. In skeletal formula, hydrogen atoms are implicit meaning they not shown in the representation, but they are there. The ends of the zig zag chains count as carbon atoms as well. This means you can draw long, complicated, branching carbon chains easily with just a few zig-zag lines. We will build on skeletal formula and drawing molecules later on.
- Two examples of compounds shown with each of these formulae are shown below:
The pharmaceutical industry uses organic compounds taken from crude oil and makes medicinal organic compounds that treat many conditions, such as:
To a chemist, calling a chemical natural or artificial is meaningless. Is a treehouse unnatural? We learn nothing by saying natural or unnatural because it does not tell us a chemicals properties. There are toxic natural substances and safe, beneficial ones. The same goes with artificial substances.
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Carbon chain length: |
Root name: |
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1 |
Meth- |
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2 |
Eth- |
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3 |
Prop- |
|
4 |
But- |
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5 |
Pent- |
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6 |
Hex- |
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7 |
Hept- |
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8 |
Oct- |
|
Functional group |
Suffix |
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Alkane |
-ane |
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Alkene |
-ene |
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Alkyne |
-yne |
|
Alcohol |
-ol |