Ch. 1 Sec. 3 Changes in Matter

physical change

alters form or appearance

of matter

change of state

change of shape/form

does not makesubstance

different substance

melting, freezing

dissolving, chopping

chemicalchange

produces new substances

different properties

Physical & Chemical Changes Game http://vital.cs.ohiou.edu/physical_chemical_change.html

electrolysis

law of conservation of mass (or matter)

• matter is not created or destroyed in any physical or chemical change

Natural gas, or methane, is the fuel used in many kitchens. When it burns, no mass is lost.

law of conservation of mass (or matter)

energy• ability to do work

or cause change

Every chemical or physical change in matter includes

a change in energy.

temperature

• average energy of random motion of particles in matter

• total energy of all particles in object

• flows from warmer cooler matter

endothermic change• energy is taken

• melting ice

• releases energy

• combustion

exothermic change

1. Identify each of the following as either a chemical or a physical change.You must give a reason for your answer.

 a. Melting candle wax. _______________________________________________

 b. Burning a candle. _________________________________________________

 c. Tearing paper. ____________________________________________________

 d. Burning paper. ___________________________________________________

 e. Dissolving table salt. _______________________________________________

 f. Mixing salt water and silver nitrate. _____________________________________

 g. Cutting pieces of magnesium ribbon. ____________________________________

 h. Mixing magnesium ribbon and HCl. _____________________________________

2. Describe two observations you might make when a physical change occurs.  

3. Describe two observations you might make when a chemical change takes place.   

Physical vs. Chemical Changes • In order to distinguish between physical and chemical changes, we study the fact that

physical changes involve something physical about the material. Physical changes can be reversed rather simply. Chemical changes involve changing the substance's chemical make-up.

Objective: To illustrate the difference between physical and chemical changes.

Materials: • 1. one empty milk jug.

2. one package of Kool-Aid per 2 quarts of water.3. sugar enough to sweeten the Kool-Aid.4. milk5. eggs6. Bisquick7. whisk8. bowl9. griddle

Procedure: • Mix water, Kool-Aid and sugar. Explain that this is a mixture that can be reversed

through the evaporation - condensation process, thus a physical change. Allow students to taste Kool-Aid.

Mix water, Bisquick and eggs according to package directions and make pancakes. Allow students to eat pancakes. Since you cannot change the pancakes back into pancake batter, this is considered a chemical change.

Activity-Chemistry in a bagIs the change physical or chemical ?

Substances Prediction-

Physical or chemical?

Reaction-Observations

Physical or chemical

calcium chloride + H20

sodium bicarbonate + H20

sodium bicarbonate + calcium chloride + H20