1. Unit 7 Lesson 1 Physical and chemical changes

2. I. Physical change A. Does not change the matter
Thermal conductivity: the rate at which a substance transfers heat
State: the physical form in which a substance exists, such as solid, liquid or gas

3. Solubility: ability of a substance to dissolve in another substance
Ductility: ability of a substance to be pulled into a wire
Malleability: ability of a substance to be rolled or pounded into thin sheets

4. B. Physical Changes do not form new substances
Physical change= change that affects one or more physical properties of a substance
Popsicle melting
Water freezing
dissolving sugar into water
The shape may change, but the substance is the same

5. Flammability= ability of the substance to burn
II. Chemical Properties A. Chemical properties= describe matter based on the ability to change into new matter that has different properties
Flammability= ability of the substance to burn
Ash & smoke cannot burn so they are nonflammable
Reactivity= ability of two or more substances to combine and form on or more new substances
Iron & oxygen will create rust over time

6. C. Chemical change
Chemical change= happens when one or more substances are changed into new substances that have new and different properties
Chemical properties are not the same as a chemical change
Properties describe what will or will not occur
Signs that a chemical change occurred:
Change in color
Odor
Fizzing
Production of heat
Foaming sound or light given off
Chemical changes change the identity of the substance

7. D. Chemical vs physical properties https://youtu.be/oF0lN0jZYx0
Physical properties can be observed WITHOUT changing the identity of the substance
Chemical properties change the substance
You have to watch the chemical reaction to know what substance originally used
chemical/physical properties/reactions with

8. E. Physical vs Chemical Change
Change in composition occurs in chemical changes
Burning wood= release carbon dioxide into the air
Physical change does NOT change the substance
Water-ice-steam= still is H2O
Physical changes can be reversed
Ice melts you can refreeze it
Chemical changes cannot be reversed easily (if not almost impossible)

9. F. Law of Conservation of Mass
Antoine Lavoisier= studied chemical changes in the 1770’s and showed that mass was not lost from chemical reactions if the gas was captured
did his experiments in glass bottles and the mass did not change
Law of conservation of mass= in ordinary chemical and physical changes, mass is not created or destroyed but is only transformed into different substances