1. Section 1 – pg 214 Observing Chemical Change
Chapter 6
Section 1 – pg 214
Observing Chemical Change

2. Review Matter: anything that has mass and takes up space
Pg 214
Review
Matter: anything that has mass and takes up space
Chemistry: the study of matter and how matter changes

3. Pg 215
Matter and Change
Changes in matter can be described in terms of physical changes and chemical changes

4. Pg 215
Matter and Change
Physical Property: a characteristic of a substance that can be observed without changing the substance into another substance
IE: Melting and boiling point, color, hardness, texture, shine, flexibility, ability to dissolve and conduct electricity or heat
Chemical Property: a characteristic of a
substance that describes its ability to change
into other substances
IE: flammability, ability to rust or tarnish

5. Pg 216
Changes of Matter
Physical Change: any change that alters the form or appearance of a substance but does not make the substance into another substance

6. Changes of Matter (cont.)
Pg 216
Changes of Matter (cont.)
Chemical Change (chemical reaction): a change in matter that produces one or two new substances
The atoms are rearranged to form new substances with different chemical and physical properties
Reactants: the substances that undergo change in a chemical reaction
Products: the new substances formed by the reaction

7. Bonding and Chemical Change
Pg 217
Bonding and Chemical Change
Chemical changes occur when bonds break and new bonds form - > new substance forms

8. Evidence for Chemical Reactions
Pg 218
Evidence for Chemical Reactions
Chemical reactions involve changes in properties and changes in energy that you can observe

9. Pg 218
Changes in Properties
One way to detect chemical reactions is to observe changes in the properties of the materials involved
IE: change in color, texture, or hardness
Precipitate: a solid that forms from solution during a chemical reaction

10. Pg 220
Changes in Energy
As matter changes, it can either absorb or release energy
Chemical reactions usually absorb heat or liberate heat
This is why an indicator that a chemical reaction occurs is temp. change
Endothermic Reaction: the total
making and breaking of bonds results
in a heat absorption of energy
Break bonds requires energy,
making bonds releases energy
B/c the reaction is taking in
heat/energy the ending temp will be higher

11. Changes in Energy (cont.)
Pg 221
Changes in Energy (cont.)
Exothermic Reaction: the total making and breaking of bonds results in a net release of energy
Energy is typically released as heat to surrounding area

12. Chapter 6 Section 1 Homework – pg 221

13. 1A. What is the difference between physical properties and chemical properties of a substance?

14. 1B. When silver coins are found in ancient shipwrecks, they are coated with a black crust. What question could you ask to help you decide whether the silver underwent a chemical change or a physical change?

15. 1C. In terms of chemical bonds and electrons, what kinds of changes occur between atoms when substances undergo chemical reactions?

16. 2A. What kinds of evidence can you use to determine if a chemical reaction has occurred?

17. 2B. How do the properties of the cooked egg shown in Figure 5 differ from the properties of a raw egg?

18. 2C. How are endothermic and exothermic reactions the same
2C. How are endothermic and exothermic reactions the same? How are they different?