Properties of Water Notes

Objectives Recognize the importance of hydrogen bonding. Explain why many compounds dissolve in water. Compare acids & bases.

Vocabulary Hydrogen bond Solution Solvent Solute Acid Base pH

Life depends on hydrogen bonds in water.

In water molecules, the oxygen atom has a slightly negative charge, and the hydrogen atoms have slightly positive charges.

Hydrogen bond Attraction between a slightly positive hydrogen atom and a slightly negative atom.

Water’s surface tension comes from hydrogen bonds that cause water molecules to stick together.

Many compounds dissolve in water.

Solution Mixture of substances in which the components are evenly distributed throughout.

Solvent Substance in a solution that is present in the greater amount and that dissolves another substance.

Solute Substance in a solution that dissolves and is present at a lower concentration than the solvent.

Some compounds form acids or bases.

H2O H+ + OH- Water Hydrogen + Hydroxide ion ion

Acid Any compound that releases H+ ions in solution.

Base Compound that removes H+ ions from a solution.

pH Measurement of acidity; related to free hydrogen ion concentration in solution.

Acidic solutions contain higher concentrations of H+ ions than pure water and have pH values below 7.

Basic, or alkaline, solutions contain lower concentrations of H+ ions than pure water and have pH values above 7.