UNIT 1: Lesson 3

Review text pp 36-43 and your note annotations (highlight, underline, star content, bracket information, write notes in the margin). Find evidence for answering the following questions by stating the page(s). Write concrete details to the questions using complete sentences. Use good grammar skills, check spelling accuracy, and use good science vocabulary.

1. What “occurs” and “does NOT occur” when a substance undergoes a “physical change?” Pg ______

2. Name 3physical properties that DO CHANGE as wool becomes a sweater and what does NOT

CHANGE? Pg ______

3. Why is changing a substance’s state of matter (solid, liquid or gas) a physical change? Use water [H2O] as

an example. Pg ______

4. Name 7 verbs that would indicate a physical change would occur. Pg ______

5. State the difference between a chemical “property” and a chemical “change” and give an example.Pg ______

6. What needs to be “rearranged” for a chemical change to alter a substance’s chemical identity? Pg ______

7. How does “temperature” cause the particles of a substance to become rearranged? Pg ______

8. Name 5 different signs that a chemical change may have occurred and give an example of each.

Pg ______

9. What does the “Law of Conservation of Mass” state? Pg ______

10. How is the Law of Conservation of Mass preserved in physical changes made to the toy robot and

to the combination of vinegar and baking soda on page 43? Pg ______

UNIT 1: Lesson 3

Review text pp 36-43 and your note annotations (highlight, underline, star content, bracket information, write notes in the margin). Find evidence for answering the following questions by stating the page(s). Write concrete details to the questions using complete sentences. Use good grammar skills, check spelling accuracy, and use good science vocabulary.

1. What “occurs” and “does NOT occur” when a substance undergoes a “physical change?”

During a physical change a substance changes from one “form” (look/appearance) to

another, but the CHEMICAL IDENTITY of the substance REMAINS THE SAME.

2. Name 3 physical properties that change as wool becomes a sweater. There is a change in

SHAPE, volume (SIZE) and texture (APPEARANCE), but the wool does NOT CHANGE

its CHEMICAL IDENTITY.

3. Why is changing a substance’s state of matter (solid, liquid or gas) a physical change? Use water

[H2O] as an example. Changing from one state of matter to another is a physical change

because although water undergoes a in its appearance (ice, liquid water, water vapor) its

CHEMICAL IDENTITY does NOT change. In all 3 different states of matter, the water is

still H2O.

4. Name 7 verbs that would indicate a physical change would occur. Stretching, DISSOLVING

(mixing and blending), cutting, MELTING (freezing/solidifying and boiling), bending,

crushing,knitting… (Pg 37) dyeing, twisting, shearing…(Pg 36)

5. What is the difference between a chemical “property” and a chemical “change and give an

example?” a chemical PROPERTY describes the chemical change that can or cannot happen

to a substance. A chemical “change” is the PROCESS the substance actually goes

throughto change into a NEW SUBSTANCE. (e.g. chemical property = flammability;

chemical change =burning)

6. What needs to be “rearranged” for a chemical change to alter a substance’s chemical identity? To

change a substance’s chemical identity the PARTICLES (atoms/molecules) and

CHEMICAL BONDS need to be rearranged.

7. How does “temperature” cause the particles of a substance to become rearranged? At higher

temperatures the particles have MORE KINETIC ENERGY (energy of motion), move

faster and more freely(not held together as tightly), and are more easily rearranged.

8. Name 5 different signs that a chemical change may have occurred and give an example of each.

PRODUCTION of an ODOR (egg rotting, milk souring, lightning), GAS(Alka Seltzer in

water) or a PRECIPITATE (solid, lead oxide precipitate forming from 2 clear liquids

chemically combining) and/or a CHANGE in COLOR (gray iron [Fe] rusting and

turning brownish-orange) and ENERGY (unlit candle changing its stored energy

(potential energy) when ignited to heat and light energy).

9. What does the “Law of Conservation of Mass” state? During chemical and physical changes,

MASS is NOT CREATED or DESTROYED, but simply CHANGES FORM or is

TRANSFORMED into differentsubstances.

10. How is the Law of Conservation of Mass preserved in the physical changes made to the toy robot

and to the combination of vinegar and baking sodaon page 43? Toy robot looks different but

has all the same parts and therefore has the same mass as it did before the parts were

switched around. The vinegar and baking soda (the reactants) have the same mass

before the reaction as the new substances (water, sodium ions and acetate ions) and the

CO2 gas contained in the balloon (theproducts) after the reaction.

[STOICHIOMETRY is the process used to ensure the Law of Conservation was preserved

during a chemical change/reaction.]