The Chemistry of Water – Polarity, Hydrogen Bonds, and DAT Applications

Water makes up over 70% of your body—and about 100% of at least 2 questions on the DAT. Whether it's biology or chemistry, the properties of water come up often and can make or break your score if you don’t know the why behind the facts.

📚 Key Concepts You Must Know

1. Polarity of Water

• Oxygen is more electronegative than hydrogen

• Electrons are pulled toward oxygen → Partial negative (δ⁻) on O, Partial positive (δ⁺) on H

• Molecule is bent (104.5° angle) → Not symmetrical = polar

🧠 Polarity = ability to hydrogen bond + dissolve polar solutes

2. Hydrogen Bonding

• Attraction between H (δ⁺) and O/N/F (δ⁻) of another molecule

• Strong intermolecular force → higher boiling point, surface tension, cohesion

💧 Examples:

• Water droplets form → cohesion

• Water moves up plants → adhesion

• Ice floats → hydrogen bonds create open lattice

3. Solubility & Water as a Solvent

• Water dissolves polar substances and ionic compounds

• “Like dissolves like” → Polar dissolves polar

• Hydrophilic = polar; Hydrophobic = nonpolar

🧠 On the DAT, solubility often comes down to polarity.

📈 DAT-Style Question Example

Q: Which of the following best explains why water has a high boiling point compared to similar molecules?
A: Hydrogen bonding between water molecules

✅ This is a classic DAT concept: polar molecules with strong intermolecular forces = higher melting/boiling points.

🎯 How to Master This for the DAT

✅ Understand why water is polar
✅ Practice identifying intermolecular vs. intramolecular forces
✅ Know examples of hydrogen bonding
✅ Review solubility trends for polar and ionic compounds
✅ Use KOTC Adaptive Q-Bank for polarity, IMF, and solubility drills

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Frequently Asked Questions (FAQs)

• How many hours should I study for the MCAT each day?

  Aim for 4-6 focused hours, ensuring you incorporate breaks to avoid burnout.

• What is the best way to handle test anxiety?

  Practice mindfulness techniques, take practice exams under realistic conditions, and maintain a balanced lifestyle.

• How can I stay motivated during the long application process?

  Set short-term goals, seek support from mentors, and reward yourself for small achievements.

• What role does exercise play in MCAT preparation?

  Regular exercise improves focus, reduces stress, and enhances overall mental clarity.

• How does King of the Curve help with MCAT preparation?

  KOTC offers personalized learning tools, gamification features, and adaptive question banks to help students stay on track without burnout.