High School Chemistry: Organic Chemistry Basics - What is Organic Chemistry - Study of, CarbonContaining Compounds

1. What This Is (In Plain English)

Organic Chemistry is the study of compounds that contain carbon, which is the backbone of life on Earth. These compounds are the building blocks of everything from the food we eat to the air we breathe.

You might be wondering why this matters. Well, without organic chemistry, we wouldn't have medicines to cure diseases, plastics to make our lives easier, or even the food we eat. Organic chemistry helps us understand how to create and manipulate these compounds to make our lives better.

2. Key Ideas & Definitions

• Carbon: A unique element that can form long chains and rings, making it the perfect building block for life.
  • Definition: Carbon is a nonmetal element that can bond with itself and other elements to form a wide variety of compounds.
  • Example: Think of a carbon atom as a LEGO brick – it can connect with other LEGO bricks to build all sorts of structures.
• Hydrocarbons: Compounds made up of only carbon and hydrogen atoms.
  • Definition: Hydrocarbons are molecules that contain only carbon and hydrogen atoms, often found in fossil fuels like gasoline and natural gas.
  • Example: Imagine a hydrocarbon as a simple LEGO castle – it's made up of just two types of blocks (carbon and hydrogen).
• Functional Groups: Specific groups of atoms within a molecule that determine its properties.
  • Definition: Functional groups are specific arrangements of atoms within a molecule that give it certain properties, like being soluble in water or reacting with other molecules.
  • Example: Think of a functional group as a special button on a LEGO brick – it determines how the brick interacts with other bricks.
• Isomers: Compounds with the same molecular formula but different structures.
  • Definition: Isomers are molecules that have the same number and types of atoms, but their arrangement is different, leading to different properties.
  • Example: Imagine two LEGO castles with the same number of bricks, but one is a square and the other is a circle – they're isomers!
• Stereochemistry: The study of the three-dimensional arrangement of atoms in a molecule.
  • Definition: Stereochemistry is the study of how atoms are arranged in space within a molecule, which affects its properties and behavior.
  • Example: Think of stereochemistry as building a LEGO castle with different shapes and sizes – the arrangement of the bricks matters!
• Alkanes: A type of hydrocarbon with only single bonds between carbon atoms.
  • Definition: Alkanes are molecules made up of only carbon and hydrogen atoms, with single bonds between the carbon atoms.
  • Example: Imagine an alkane as a simple LEGO chain – it's a straight line of connected bricks.
• Alkenes: A type of hydrocarbon with at least one double bond between carbon atoms.
  • Definition: Alkenes are molecules made up of only carbon and hydrogen atoms, with at least one double bond between the carbon atoms.
  • Example: Think of an alkene as a LEGO chain with a bend in it – it's a bit more complex than an alkane.
• Alkynes: A type of hydrocarbon with at least one triple bond between carbon atoms.
  • Definition: Alkynes are molecules made up of only carbon and hydrogen atoms, with at least one triple bond between the carbon atoms.
  • Example: Imagine an alkyne as a LEGO chain with a big bend in it – it's even more complex than an alkene.
• Aromatic Compounds: A type of hydrocarbon with a ring structure and alternating double bonds.
  • Definition: Aromatic compounds are molecules made up of only carbon and hydrogen atoms, with a ring structure and alternating double bonds.
  • Example: Think of an aromatic compound as a LEGO ring – it's a special shape that's different from other hydrocarbons.

3. How To Do It (Step-by-Step)

Drawing a Lewis Structure

1. Start with the molecular formula: Write down the number and types of atoms in the molecule, separated by dashes (e.g., CH4).
2. Determine the central atom: Identify the atom that will be the center of the molecule, usually the atom with the most bonds (e.g., carbon in CH4).
3. Draw single bonds: Connect the central atom to the surrounding atoms with single bonds, using dots to represent the electrons (e.g., H-C-H).
4. Add double bonds: If necessary, add double bonds between atoms to satisfy the octet rule (e.g., H=C=H).
5. Add lone pairs: Add lone pairs to the atoms that need them to satisfy the octet rule (e.g., H-C-H with lone pairs on the hydrogen atoms).
6. Check the structure: Make sure the Lewis structure has the correct number of bonds and lone pairs, and that the octet rule is satisfied.

Example:

Molecular formula: CH4

Central atom: Carbon

Single bonds: H-C-H

Double bonds: None

Lone pairs: H-C-H with lone pairs on the hydrogen atoms

Lewis structure: H-C-H with lone pairs on the hydrogen atoms

4. Watch Out! (Common Mistakes)

• Mistake: Forgetting to add lone pairs to atoms that need them.
  • Fix: Remember that atoms need lone pairs to satisfy the octet rule, and add them accordingly.
• Mistake: Drawing double bonds between atoms that don't need them.
  • Fix: Check the molecular formula and the octet rule to determine if double bonds are necessary.
• Mistake: Not checking the structure for errors.
  • Fix: Double-check the Lewis structure to make sure it has the correct number of bonds and lone pairs, and that the octet rule is satisfied.

5. Practice Problems

Problem 1:

Draw the Lewis structure for the molecule CH2O.

Solution:

1. Start with the molecular formula: CH2O
2. Determine the central atom: Oxygen
3. Draw single bonds: O-C-H
4. Add double bonds: None
5. Add lone pairs: O-C-H with lone pairs on the oxygen and hydrogen atoms
6. Check the structure: Make sure the Lewis structure has the correct number of bonds and lone pairs, and that the octet rule is satisfied.

Lewis structure: O=C-H with lone pairs on the oxygen and hydrogen atoms

Problem 2:

Draw the Lewis structure for the molecule C2H6.

Solution:

1. Start with the molecular formula: C2H6
2. Determine the central atom: Carbon
3. Draw single bonds: H-C-C-H
4. Add double bonds: None
5. Add lone pairs: H-C-C-H with lone pairs on the hydrogen atoms
6. Check the structure: Make sure the Lewis structure has the correct number of bonds and lone pairs, and that the octet rule is satisfied.

Lewis structure: H-C-C-H with lone pairs on the hydrogen atoms

6. Cram Sheet

• Carbon is the backbone of life on Earth.
• Hydrocarbons are compounds made up of only carbon and hydrogen atoms.
• Functional groups determine the properties of a molecule.
• Isomers are compounds with the same molecular formula but different structures.
• Stereochemistry is the study of the three-dimensional arrangement of atoms in a molecule.
• Alkanes are a type of hydrocarbon with only single bonds between carbon atoms.
• Alkenes are a type of hydrocarbon with at least one double bond between carbon atoms.
• Alkynes are a type of hydrocarbon with at least one triple bond between carbon atoms.
• Aromatic compounds are a type of hydrocarbon with a ring structure and alternating double bonds.
• Lewis structures are diagrams that show the arrangement of electrons in a molecule.

7. Where to Learn More

• YouTube: Crash Course Chemistry (a fun and engaging channel that covers chemistry topics, including organic chemistry)
• PhET Simulation: Organic Chemistry (a interactive simulation that allows you to explore the properties of organic compounds)
• School-friendly website: Khan Academy (a website that offers free online courses and resources, including organic chemistry)