Water: Polarity, Hydrogen Bonding, and pH (Lecture Notes)

Flashcards covering polarity, hydrogen bonding, solubility, cohesion/adhesion/surface tension, density of ice, universal solvent, and pH concepts.

Polar molecule with a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms.

What is the polarity of a water (H2O) molecule?

The oxygen atom.

Which atom in a water molecule bears the partial negative charge due to higher electronegativity?

Hydrogen bonds (weak electrical attractions).

What type of bond forms between water molecules due to polarity?

An asymmetrical distribution of electrical charge with opposite charges on opposite ends.

What does 'polar molecule' mean in terms of charge distribution?

Hydrophilic.

What term describes a substance that dissolves readily in water?

Hydrophobic.

What term describes substances that do not dissolve readily in water (like oil)?

A molecule having both hydrophobic and hydrophilic regions.

What is amphipathic?

Because its polarity allows it to dissolve many other substances.

Why is water often called the universal solvent?

Water is a liquid; many similar-sized substances are gases.

What are the physical states of water relative to many substances of similar size at moderate temperatures?

It gives water a strong resistance to temperature change (high heat capacity).

How does water's hydrogen bonding affect its heat properties?

Water molecules sticking to each other.

What is cohesion in water?

Water molecules clinging to other substances.

What is adhesion in water?

Cohesion among water molecules at the surface.

What causes surface tension in water?

Ice expands and is less dense than liquid water, so it floats.

What happens to water when it freezes?

The concentration of H+ (hydrogen ions) in solution.

What does pH measure?

Acidic.

If a solution has more H+ than OH-, what is the solution called?

Basic (alkaline).

If a solution has more OH- than H+, what is the solution called?

A neutral solution.

What is formed when an acid reacts with a base?

Sodium ions (Na+) and chloride ions (Cl-).

What ions are produced when common salt (NaCl) dissolves in water?