2.2 Power Notes Power Notes 37 PROPERTIES OF WATER Polar molecules: SECTION 2.2 PROPERTIES OF WATER Power Notes Polar molecules: Atom: Charge: 1. 2. Explain: Nonpolar molecules: Atom: Charge: Chemistry of Life CHAPTER 2 Properties of water related to hydrogen bonds: 1. 2. 3. Copyright © McDougal Littell/Houghton Mifflin Company. Solutions: Solvents: Solutes: Acids: Neutral: Bases: pH: pH: pH: Unit 1 Resource Book McDougal Littell Biology Power Notes 37

Let’s test a Property of water! 1. Yes; the photo shows fire, which is a chemical reaction. 2. The chemical reaction known as fire involves a fuel source and oxygen. 3. While heat and light are produced, the chemical products of this reaction are gases, such as carbon dioxide and water

Do Now Log: Correctly draw a water molecule and label the polarity.

Common misconceptions practice True or False Water is an element. Hydrogen bonds occur between water molecules. Capillary action is adhesion. Strong bonds are better than weak bonds. Food is different from the macromolecules that form cells. Proteins are shaped the same. DNA and RNA are the only molecules made of nucleotides. The bonds between hydrogens and the oxygen in water are covalent. 1. F 2. T 3. F 4. F 5. F 6. F 7. F 8. T

Why didn’t the dollar bill burn? Demo: Why didn’t the dollar bill burn?

KEY CONCEPT Water’s unique properties allow life to exist on Earth.

Life depends on hydrogen bonds in water. Water is a polar molecule. Polar molecules have slightly charged regions. O H _ + Nonpolar molecules do not have charged regions. (1)Hydrogen bonds (2)form between slightly positive    hydrogen atoms and slightly negative atoms.

Hydrogen bonds are responsible for three important properties of water. high specific heat cohesion adhesion

1. High Specific Heat- a large amount of energy is needed to produce an increase in temperature. 2. Cohesion- water molecules “stick” to each other 3. Adhesion – water molecules “stick to other substances

4. Water expands upon freezing. Ice floats! Adhesion and cohesion allow water to move up tubes (capillary action) 4. Water expands upon freezing. Ice floats!

Many compounds dissolve in water. A solution is formed when one substance dissolves in another. A solution is a homogeneous mixture. Solvents dissolve other substances. Solutes dissolve in a solvent. solution

Write this below the last 3 boxes! “Like dissolves like.” Polar solvents dissolve polar solutes. Nonpolar solvents dissolve nonpolar solutes. Polar substances and nonpolar substances generally remain separate.

Some compounds form acids or bases. An acid releases a hydrogen ion when it dissolves in water. high H+ concentration pH less than 7 more acidic stomach acid pH between 1 and 3

A base removes hydrogen ions from a solution. low H+ concentration pH greater than 7 bile pH between 8 and 9 more basic

A neutral solution has a pH of 7. pure water pH 7

Closing Quiz 1. Why is water polar. 2. What is a hydrogen bond. 3 Closing Quiz 1. Why is water polar? 2. What is a hydrogen bond? 3. Draw several water molecules. Include charges, lines for covalent bonds, dashes for hydrogen bonds.

Closing Quiz (write your answers at the bottom of the notes handout) 1. Name a polar molecule. 2. Name a nonpolar molecule. 3. Why does capillary action happen? 4. Why does ice float?

Properties of Water by the Amoeba Sisters https://www.youtube.com/watch?v=3jwAGWky98c