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Holt Chemistry - Chapter Review P.30-31

1. What is chemistry?
-Chemistry is the study of chemicals, their properties, and the reactions in which they are involved.

2. What are the commonphysical states of matter, and how do they differ from one another?
-There are three principal states, which are solid, liquid and gas. Their differences are that in the gas state, the particlescan move freely

3. Explain the difference between a physical and a chemical change.
-Physical changes are the ones in which the identity of the substance doesn't change. In a chemical changethis happens and also a new substance is formed.

11. Your friend mentions that she eats only natural foods because she wants her food to be free of chemicals. What is wrong with this reasoning?-Chemicals are not necesarilly added to the foods, whenever you're cooking food you are carrying out a chemical reaction.

12. Determine whether each of the following substances would be a gas,a liquid, or a solid if found in your classroom.
a.gas
b.solid
c.solid
d.gas
e.liquid

13. Is toasting bread an example of a chemical change? Why or why not?- No, it just affects the physical properties of the bread, it doesn't change the identity of the substance nor is a new substance created.

14. Classify each of the following as a physicalchange or a chemical change, and describe the evidence that suggests a change is taking place.
a.Physical, you're just separating the particles.
b.Chemical, a reacton takes place betweenthe bleach and the stain in order for it to disappear.
c. Physical, no new substance is creating, the state is the one that changes the wax from solid to liquid.
d. Physical, the statechanges, not the whole substance.

24. Use particles models to explain why liquids and gases take the shape of their containers.

25. You are given a sample of colorless liquid in a beaker. What...