P.153 #1,2,3,5,7,13,15

Feb.16
Page 153 Questions Number 1,2,3,5,7,13,15

1.Name two properties of matter.
Ans: Matter is anything that has mass and takes up space.

2.What are the categories of pure substances in the matter classification tree shown in Figure 4.5 on page 143.
Ans:  Pure substances have 2 categories: Compounds and Elements.

3.How is an element different from a compound?
Ans: A compound is a pure substance that is made from 2 or more elements that are combined together
chemically.

5.What is the relationship between an element's atomic number and the number of protons in the nucleus of each of its atoms?
Ans: The atomic number of an element is the same number of the amount of protons it has.

7.What is an ion?
Ans: An ion is a electrically charged atom (negative or positively charged). Atoms are charged as they lose or gain electrons during chemical change.

13.Suppose you place a kettle on a stove and boil some water. Is the steam that forms evidence of a chemical change or physical change? Explain.
Ans: The steam that is formed by boiling water is a physical change. Nothing new is created, the steam is just water in another form.

15.Describe three things about atoms that you did not know before starting work on this section.
Ans: Before working on this section i didn't know that atoms had smaller particles within it and i didn't know the relationship between the atomic number and the number of protons. It was also surprising when i learned that electrons in an atom does not stay put and that they are constantly moving.