High School Chemistry: Organic Chemistry Basics - Everyday Organic Compounds - Sugar, Vinegar, Gasoline, Soap

Everyday Organic Compounds: Sugar, Vinegar, Gasoline, and Soap

1. What This Is (In Plain English)

Organic compounds are molecules made from carbon and hydrogen (and sometimes other elements) that we find in everyday things like food, drinks, and household items.

These compounds matter because they're all around us, and we use them every day. Without them, we wouldn't have yummy foods like sugar, refreshing drinks like vinegar, or the gasoline that powers our cars. We also use soap to clean ourselves, and it's made from organic compounds too!

2. Key Ideas & Definitions

• Carbon: A special element that can form long chains or rings with other atoms.
  • Definition: Carbon is like a LEGO brick that can connect with other bricks to make all sorts of shapes.
  • Example: Think of a carbon atom as a LEGO brick that can connect with other bricks to make a long chain, like a sugar molecule.
• Hydrogen: A light element that often connects with carbon atoms.
  • Definition: Hydrogen is like a tiny LEGO brick that connects to carbon bricks to make a strong bond.
  • Example: Imagine hydrogen atoms as tiny LEGO bricks that connect to carbon bricks to make a strong chain, like a gasoline molecule.
• Functional Groups: Special groups of atoms that determine the properties of an organic compound.
  • Definition: Functional groups are like special labels on a LEGO box that tell you what kind of shape the LEGO set will make.
  • Example: Think of a functional group as a label on a LEGO box that says "make a sweet treat" or "make a cleaning agent".
• Isomers: Molecules with the same atoms but in a different order.
  • Definition: Isomers are like two different LEGO sets that have the same pieces but are built in a different way.
  • Example: Imagine two different LEGO sets that have the same pieces but are built in a different order, like a sugar molecule and a different sugar molecule.
• Stereoisomers: Molecules with the same atoms and order but a different 3D shape.
  • Definition: Stereoisomers are like two different LEGO sets that have the same pieces and are built in the same way, but one set is upside down.
  • Example: Think of two different LEGO sets that have the same pieces and are built in the same way, but one set is upside down, like a sugar molecule and its mirror image.
• Polar and Nonpolar Molecules: Molecules with a charge or no charge.
  • Definition: Polar molecules are like a magnet that has a north and south pole, while nonpolar molecules are like a ball that has no charge.
  • Example: Imagine a polar molecule as a magnet that has a north and south pole, while a nonpolar molecule is like a ball that has no charge.
• Acids and Bases: Molecules that can donate or accept a proton (H+ ion).
  • Definition: Acids are like superheroes that can give away their proton, while bases are like superheroes that can take a proton.
  • Example: Think of an acid as a superhero that can give away its proton, while a base is like a superhero that can take a proton.
• Solubility: The ability of a molecule to dissolve in a solvent.
  • Definition: Solubility is like how well a LEGO set can fit into a LEGO box.
  • Example: Imagine a molecule as a LEGO set that can fit into a LEGO box, while a solvent is like the LEGO box that can hold the set.
• Vapor Pressure: The pressure of a gas above a liquid.
  • Definition: Vapor pressure is like the pressure of a balloon that's filled with gas.
  • Example: Think of vapor pressure as the pressure of a balloon that's filled with gas, like the pressure of a gasoline vapor above a liquid.

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

Drawing a Lewis Structure

1. Write the molecular formula of the compound, like CH4 for methane.
2. Draw a skeleton of the molecule, using lines to connect the atoms.
3. Add electrons to the molecule, using dots to represent the electrons.
4. Use the octet rule to determine the number of electrons each atom should have.
5. Add or remove electrons to satisfy the octet rule, and draw the final Lewis structure.

Example: Drawing the Lewis Structure of Methane (CH4)

1. Write the molecular formula: CH4
2. Draw a skeleton of the molecule:
   • C (carbon) is the central atom
   • H (hydrogen) atoms are connected to the C atom
3. Add electrons to the molecule:
   • C atom has 4 electrons
   • H atoms have 1 electron each
4. Use the octet rule to determine the number of electrons each atom should have:
   • C atom should have 8 electrons
   • H atoms should have 2 electrons each
5. Add or remove electrons to satisfy the octet rule:
   • C atom needs 4 more electrons
   • H atoms need 1 more electron each
6. Draw the final Lewis structure:

Calculating the Molar Mass of a Compound

1. Write the molecular formula of the compound, like C6H12O6 for glucose.
2. Look up the atomic masses of each element in the compound.
3. Multiply the atomic mass of each element by the number of atoms in the compound.
4. Add up the masses of all the elements to get the molar mass of the compound.

Example: Calculating the Molar Mass of Glucose (C6H12O6)

1. Write the molecular formula: C6H12O6
2. Look up the atomic masses:
   • C = 12.01 g/mol
   • H = 1.008 g/mol
   • O = 16.00 g/mol
3. Multiply the atomic mass of each element by the number of atoms in the compound:
   • C: 6 x 12.01 = 72.06 g/mol
   • H: 12 x 1.008 = 12.096 g/mol
   • O: 6 x 16.00 = 96.00 g/mol
4. Add up the masses of all the elements:
   • 72.06 + 12.096 + 96.00 = 180.156 g/mol

4. Watch Out! (Common Mistakes)

Mistake: Not using the octet rule when drawing a Lewis structure.

Fix: Remember to use the octet rule to determine the number of electrons each atom should have. Think of it like a game where each atom wants to have 8 electrons to be happy!

Mistake: Not considering the polarity of a molecule when calculating its boiling point.

Fix: Remember that polar molecules have a higher boiling point than nonpolar molecules. Think of it like a magnet that's harder to move than a ball that has no charge.

Mistake: Not considering the solubility of a molecule when calculating its density.

Fix: Remember that molecules that are soluble in a solvent will have a higher density than molecules that are not soluble. Think of it like a LEGO set that fits into a LEGO box, while a molecule that doesn't fit into the box will have a lower density.

5. Practice Problems

Problem 1: Drawing a Lewis Structure

Draw the Lewis structure of the molecule CH3OH.

Solution:

1. Write the molecular formula: CH3OH
2. Draw a skeleton of the molecule:
   • C (carbon) is the central atom
   • H (hydrogen) atoms are connected to the C atom
   • O (oxygen) atom is connected to the C atom
3. Add electrons to the molecule:
   • C atom has 4 electrons
   • H atoms have 1 electron each
   • O atom has 6 electrons
4. Use the octet rule to determine the number of electrons each atom should have:
   • C atom should have 8 electrons
   • H atoms should have 2 electrons each
   • O atom should have 8 electrons
5. Add or remove electrons to satisfy the octet rule:
   • C atom needs 4 more electrons
   • H atoms need 1 more electron each
   • O atom needs 2 more electrons
6. Draw the final Lewis structure:

Problem 2: Calculating the Molar Mass of a Compound

Calculate the molar mass of the compound C2H6O.

Solution:

1. Write the molecular formula: C2H6O
2. Look up the atomic masses:
   • C = 12.01 g/mol
   • H = 1.008 g/mol
   • O = 16.00 g/mol
3. Multiply the atomic mass of each element by the number of atoms in the compound:
   • C: 2 x 12.01 = 24.02 g/mol
   • H: 6 x 1.008 = 6.048 g/mol
   • O: 1 x 16.00 = 16.00 g/mol
4. Add up the masses of all the elements:
   • 24.02 + 6.048 + 16.00 = 46.068 g/mol

Takeaway: Remember to use the octet rule when drawing a Lewis structure, and consider the polarity and solubility of a molecule when calculating its boiling point and density.

6. Cram Sheet

• Carbon: A special element that can form long chains or rings with other atoms.
• Hydrogen: A light element that often connects with carbon atoms.
• Functional Groups: Special groups of atoms that determine the properties of an organic compound.
• Isomers: Molecules with the same atoms but in a different order.
• Stereoisomers: Molecules with the same atoms and order but a different 3D shape.
• Polar and Nonpolar Molecules: Molecules with a charge or no charge.
• Acids and Bases: Molecules that can donate or accept a proton (H+ ion).
• Solubility: The ability of a molecule to dissolve in a solvent.
• Vapor Pressure: The pressure of a gas above a liquid.
• Molar Mass: The mass of one mole of a substance.

7. Where to Learn More

• YouTube Channels: Amoeba Sisters, Crash Course Chemistry
• PhET Simulations: Organic Chemistry, Molecular Structure
• School-Friendly Websites: Khan Academy, Chemistry LibreTexts