Simple Molecule Examples: Water, Oxygen, CO2

📚 Quick Study Guide

• 💧 Water ($H_2O$): Two hydrogen atoms covalently bonded to one oxygen atom. It's a polar molecule due to the difference in electronegativity between oxygen and hydrogen. This polarity leads to hydrogen bonding, which is crucial for many of water's unique properties.
• 🫁 Oxygen ($O_2$): Two oxygen atoms bonded together through a double covalent bond. It exists as a diatomic molecule at room temperature and is essential for respiration.
• 🔥 Carbon Dioxide ($CO_2$): One carbon atom double-bonded to two oxygen atoms. It's a linear, nonpolar molecule. It's a product of respiration and combustion, and is a greenhouse gas.
• ⚛️ Covalent Bond: A chemical bond that involves the sharing of electron pairs between atoms. These bonds are strong and are essential for the formation of molecules.
• ⚖️ Molecular Polarity: A measure of the unequal sharing of electrons in a molecule. Polar molecules have a partial positive charge on one side and a partial negative charge on the other, influencing their interactions with other molecules.

🧪 Practice Quiz

1. Which of the following is the chemical formula for water?
   1. A. $O_2$
   2. B. $CO_2$
   3. C. $H_2O$
   4. D. $CH_4$
2. What type of bond holds the oxygen atoms together in $O_2$?
   1. A. Ionic bond
   2. B. Hydrogen bond
   3. C. Single covalent bond
   4. D. Double covalent bond
3. Which molecule is linear and nonpolar?
   1. A. $H_2O$
   2. B. $CO_2$
   3. C. $O_2$
   4. D. $NH_3$
4. Which property of water is due to its polarity?
   1. A. Low boiling point
   2. B. Ability to dissolve nonpolar substances
   3. C. High surface tension
   4. D. Low density as a solid
5. What is the role of $O_2$ in respiration?
   1. A. To produce glucose
   2. B. To remove carbon dioxide
   3. C. To accept electrons
   4. D. To provide energy directly
6. What is the shape of the water molecule ($H_2O$)?
   1. A. Linear
   2. B. Trigonal planar
   3. C. Bent
   4. D. Tetrahedral
7. Which of the following is a product of combustion?
   1. A. $H_2O$ only
   2. B. $CO_2$ only
   3. C. Both $H_2O$ and $CO_2$
   4. D. $O_2$ only