Question

1. which of the following is a clue of a chemical change?

a. iron changes color when heated
b. a gas forms when vinegar and baking soda are mixed
c. gas bubbles form in boiling water
d. balls of wax form when melted wax is poured into ice water

1. describe how the melting of ice is a change in physical properties.

a. it changes from a gas state to a solid state without changing its chemical composition.
b. it changes from a liquid state to a solid state without changing its chemical composition.
c. it changes from a solid state to a liquid state without changing its chemical composition.
d. it changes from a solid state to a gas state without changing its chemical composition.

1. which of the following is not an example of a physical change?

a. crumpled paper b. pencil sharpening c. shrunk - clothing d. rust

1. fizzing, foaming, and burning are all examples of

a. sustainability b. physical change c. chemical change d. properties

1. what is matter?

a. a substance that takes part in and undergoes a change in reaction
b. anything that has mass and takes up space
c. solids, liquids and gases
d. substances released during a chemical change

1. what sign of a chemical change is evident in a fire?

a. color change b. producing heat c. light produced d. all of the choices are correct

1. which of the following is true?

a. dissolving candy is a physical change because a new substance is not formed, this can be reversed.
b. dissolving candy is a physical change because the color changed.
c. dissolving is a chemical change because its irreversible.
d. all of the choices are correct

1. what is the main difference between a chemical change and a physical change?

a. chemical changes the substances identity; physical does not
b. physical changes the substances identity; chemical does not
c. chemical changes what it looks like; physical does not
d. physical changes everything; chemical only changes some things

Explanation:

1. a. Iron changing color when heated is a chemical change (rusting). b. Gas forming when vinegar and baking soda are mixed is a chemical change. c. Gas bubbles forming when water is poured into ice - water is a physical change (due to temperature change affecting gas solubility). d. Balls of wax forming when melted wax cools is a physical change.
2. Melting of ice is a physical change as it changes from solid to liquid without changing chemical composition (answer is d).
3. a. Crumpled paper is a physical change (shape change). b. Pencil sharpening is a physical change (shape change). c. Shrunk clothing is a physical change (size change). d. Rust is a chemical change (iron oxidation).
4. Fizzing, foaming, and burning are chemical changes as new substances are formed.
5. Matter is a substance that has mass and takes up space (answer is b).
6. In a fire, color change, heat production, and light production are signs of chemical change (answer is d).
7. Dissolving candy is a physical change because no new substance is formed and it can be reversed (answer is a).
8. The main difference is that chemical changes change the substance's identity while physical changes do not (answer is a).

Answer:

1. c
2. d
3. d
4. c
5. b
6. d
7. a
8. a