Water, pH and Buffer Solutions

📋 Course Outline

1. Water Structure and Polarity
2. Hydrogen Bonds in Water
3. Hydrophilic and Hydrophobic Interactions
4. Water Ionization and pH
5. Acids, Bases and Conjugate Pairs
6. Buffer Solutions and pKa

📖 1. Water Structure and Polarity

🔑 Key Concepts & Definitions

• Water molecule : Contains two hydrogen atoms and one oxygen atom linked by covalent bonds, with an H–O–H angle of 104.5°.

📝 Essential Points

• The water molecule has a globally neutral charge, but oxygen is more electronegative than hydrogen, giving each hydrogen a partial charge of +0.41 and oxygen a partial charge of −0.82.

💡 Memory Hook

A bent water molecule with two partially positive hydrogens and one partially negative oxygen

📖 2. Hydrogen Bonds in Water

🔑 Key Concepts & Definitions

• Hydrogen bond : An interaction in which the partial positive charge of one molecule interacts with the partial negative charge of another molecule.

★ Must-know

📌 In ice, four stable hydrogen bonds per water molecule form a crystalline network; in liquid water, hydrogen bonds are fewer and last 10−8 to 10−11 seconds; in water vapor, intermolecular interactions are absent.

Further detail