Lesson Overview Lesson Overview Properties of Water Objectives 2.2 Water - - Discuss the unique properties of water. -Differentiate between solutions and suspensions. -Explain what acidic solutions and basic solutions are.

Lesson Overview Lesson Overview Properties of Water Vocabulary WordDefinition Hydrogen bond Weak attraction between hydrogen atom and another CohesionAttraction between molecules of the same substance (water with water) AdhesionForce of attraction between different kinds of molecules (water and other stuff) SolutionType of mixture in which all the components are evenly distributed SoluteSubstance that is dissolved in a solution SolventDissolving substance in a solution pH scaleScale with values from 0-14, used to measure the concentration of H+ ions in a solution: can be acid, neutral or basic AcidCompound that produces hydrogen ions in solution, pH less than 7 BaseCompound that produces hydroxide ions (OH-) in solution, pH more than 7 BufferCompound that prevents sharp, sudden changes in pH

Lesson Overview Lesson Overview Properties of Water Polarity A molecule in which the charges are unevenly distributed is said to be “polar”.

Lesson Overview Lesson Overview Properties of Water Hydrogen Bonding Because of their partial positive and negative charges, polar molecules such as water can attract each other. This attraction is known as a hydrogen bond. *Hydrogen bonds are the weakest type of chemical bond.*

Lesson Overview Lesson Overview Properties of Water Cohesion Cohesion is an attraction between molecules of the same substance.

Lesson Overview Lesson Overview Properties of Water Adhesion Adhesion is an attraction between molecules of different substances.

Lesson Overview Lesson Overview Properties of Water Heat Capacity Because of the multiple hydrogen bonds between water molecules, it takes a large amount of heat energy raise or cool the temperature water.

Lesson Overview Lesson Overview Properties of Water Solutions When all components of a substance dissolve in water, it creates a solution.

Lesson Overview Lesson Overview Properties of Water Suspensions Some materials do not dissolve when placed in water, but separate into pieces. Such mixtures are known as suspensions.

Lesson Overview Lesson Overview Properties of Water Acids, Bases, and pH Water molecules sometimes split apart to form hydrogen ions and hydroxide ions.

Lesson Overview Lesson Overview Properties of Water The pH Scale Chemists devised a measurement system called the pH scale to indicate the concentration of H + (hydrogen) ions in solution. The pH scale ranges from 0 to 14.

Lesson Overview Lesson Overview Properties of Water The pH Scale Solutions with a pH below 7 are called acidic because they have more H + ions. The lower the pH, the greater the acidity. Solutions with a pH above 7 are called basic because they have less H + ions. The higher the pH, the more basic the solution.

Lesson Overview Lesson Overview Properties of Water Buffers Buffers are any substance that brings a solutions pH back to 7 (or neutral), this is especially important in the human body.