Read each statement and identify it as an example of a physical or chemical change.

1. Chopping wood2. Dissolving salt in water3. Cooking egg white4. A juice box in the freezer5. Gasoline is ignited6. Jewelry tarnishes

Think back to middle school physical science class

Write a definition of a physical and a chemical change.

• 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

2H2O2 H2O+ O2 (g)

Chemical Reactions Lab

Wear goggles at all time!!!Do not touch any liquid in the beakerIf you spill a liquid, call teacher.Wash glassware with the special soap and brush. Dry with towel.Keep work area neat.

Safety Procedures

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?

Materials:

Weigh boat

Spatula

Graduated cyliner

beaker

Glass stirring rod

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 40.0g5. Carefully pour the Epsom salt into the beaker.

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.

Data Key:Red – Epsom SaltBlue – Calcium Chloride