1. Unit 2 Lesson 1: Properties of Water 1.D – Adhesion and Cohesion are caused by hydrogen bonds. Hydrogen bonds are formed because of polar covalent bonds between the oxygen and hydrogen's atoms in a water molecule. 2.A – Water is less dense when it freezes, therefore ice floats. 3.A – Cohesion holds the droplets together and adhesion holds them onto the pine needles.

2. 4. C – Water absorbs heat when it changes from a liquid to a vapor. Unit 2 Lesson 1: Properties of Water

3. Part A Answer: A combination of cohesion and adhesion contribute to capillary action within the xylem. The transport of water begins when water evaporates from inside the leaf. Due to cohesion, adjacent water molecules are pulled upwards along re-placing the evaporated molecules. The adhesion of water molecules to plant cell walls helps water to resist the downward pull of gravity holding it in place in the xylem. Unit 2 Lesson 1: Properties of Water

4. Part B Answer: Cavitation, the formation of air bubbles within the xylem separates the water molecules. The water molecules below the cavitation bubble can no longer create hydrogen bonds with the molecules above the cavitation bubble. So when the molecule are pulled upward through the xylem, the molecules below the cavitation bubble are left behind. Unit 2 Lesson 1: Properties of Water

5. Unit 2 Lesson 2: Organic Molecule 1.A – Carbon can form 4 covalent bonds. 2.D – Wax, saturated fat and phospholipids are all lipids. Polysaccharide is a carbohydrate. 3.C – Dehydration synthesis joins monomers to create polymers while releasing a water molecule for each monomer joined. Glucose is a monomer. 4.D – it is a phospholipid. Region 2 is the fatty acid chain which is nonpolar.

6. Part A Answer: A fat or oil molecule consists of three fatty acid chains joined to a single molecule of glycerol. The fatty acid chains are almost entirely hydrogen and carbon. Unit 2 Lesson 2: Organic Molecule

7. Part B Answer: Carbohydrates have a 1:2:1 ratio of carbon hydrogen and oxygen. Lipids are mostly carbon and hydrogen. Monomers of carbohydrates can be connected together to form long chains. Lipids to not have a monomer form. Unit 2 Lesson 2: Organic Molecule

8. Part C Answer: Fats and carbohydrates store energy for the organism. They can be broken down by cells to provide ATP.