1. Read each statement and identify it as an example of a physical or chemical change. 1.Chopping wood 2.Dissolving salt in water 3.Cooking egg white 4.A juice box in the freezer 5.Gasoline is ignited 6.Jewelry tarnishes Think back to middle school physical science class

2. Write a definition of a physical and a chemical change.

3. Illustrate how old substances become new substances. Old substances are called reactants. New substances are called products. A chemical reaction uses an arrow to indicate the change. It is read as ‘yields’. Chemical Reaction 2H 2 O 2  H 2 O+ O 2 (g)

4. Chemical Reactions Lab Wear goggles at all time!!! Do not touch any liquid in the beaker If you spill a liquid, call teacher. Wash glassware with the special soap and brush. Dry with towel. Keep work area neat. Safety Procedures

5. Pre-lab Questions Check 1.Write the chemical equation for cellular respiration. 2.Define exothermic reaction. 3.Define endothermic reaction. 4.What type of data will you be collecting to indicate a chemical reaction? 5.What part of the chemical reaction is missing from equation #1 in Write the chemical equation for photosynthesis. 6.the objective section? 7.How will determine which of the reactions is exothermic? endothermic?

6. Materials: Weigh boat Spatula Graduated cyliner beaker Glass stirring rod

7. How to Use a Balance 1.Press the Tare or Zero Button. 2.When you see a 0.00g reading, place weigh boat on the balance. 3.Press the Tare or Zero Button again. 4.When you see a 0.00g reading, begin adding the Epsom salt (magnesium sulfate) until you read 40.0g 5.Carefully pour the Epsom salt into the beaker.

8. Epsom Salt Throw out weigh boat in trash Run water in sink and pour the dissolved epsom salt down the drain. Use soap and brush to wash the beaker and stirring rod. Using wet paper towel, wipe off temperature sensor. Calcium chloride Throw out weigh boat in bin of water. Store data on P-drive and/or USB Shut down computer. Wait until computer has completely shut down to close it. Return to computer cart. Gently wash the temperature sensor. Dry and put in bag. Run water in sink and pour the dissolved calcium chloride down the drain. Be careful, it may be hot. Wash your hands. Clean Up Procedure Be sure to complete the lab assignment: Write (10) Observations.

9. Data Key: Red – Epsom Salt Blue – Calcium Chloride