help in chemistry

1. Which of the following are pure substances?

(a) vitamin tablet
(b) glass
(c) carbon monoxide (d) wine
(e) helium

100

CHAPTER 3 PROPERTIES OF MATTER: OPPOSITES ATTRACT

2. 3.

4. 5.

What is the fundamental difference between pure substances and mixtures?

Distinguish between homogeneous and heterogeneous mixtures. Give a specific example of each. Do not use examples given in the text.

Explain the difference between a phase and a physical state.

Which of the following are homogeneous mixtures?

(a) chocolate chip ice cream (b) clean, dry air
(c) popcorn
(d) mercury

(e) steel

Which one of the following describes a chemical property of gold?

A. Gold is a yellow metal.
B. Gold is a nonreactive metal.
C. Gold is a soft metal.
D. Gold is a very dense metal.
E. Gold is a good conductor of heat and electricity.

Which of the following are primarily chemical changes?

(a) grinding rocks into sand
(b) leaves turning red in autumn
(c) instant coffee dissolving in water (d) evaporating alcohol
(e) explosion of a firecracker
(f) hard-boiling of an egg

Distinguish between the electrostatic force and the nuclear force.

6.

7.

8.

CHAPTER 3 PROPERTIES OF MATTER: OPPOSITES ATTRACT 101 9. Complete the following table with the appropriate data. Unless indicated

otherwise, assume each line refers to a neutral atom.

Element	Symbol	Atomic number	Mass number	Number of protons	Number of neutrons	Number of electrons
25	55
bromine	44
197Au3+
42	33
31	15	18

10. Where is most of the mass of an atom found?

11. Describe how cations and anions are formed.

12. What are the two primary types of chemical compounds? How do they differ from each other?

13. Determine the name or formula for each of the following.

barium acetate _________________

CuSO4 ______________________

CCl4 ______________________

K2S _______________________

H2SO3 _____________________

NO2 ________________________

14. oxalic acid ____________________

15. iron(III) hydroxide ______________

16. ammonium carbonate ____________

17. sodium phosphate _______________

CHAPTER 3 PROPERTIES OF MATTER: OPPOSITES ATTRACT

Identify each of the following substances as ionic or molecular.
HCN _________

NH3 _________

CS2 _________

KClO3 _________

Write the formula of the compound that is likely to form between:

silver and oxygen ____________


zinc and iodine ____________

How many hydrogen atoms are there in each molecule of (C2H5)2NH?

What is the fundamental difference between a chemical and physical change?

A single compound that is a liquid at room temperature is most likely what type of compound (ionic or molecular)? Indicate two likely general properties of this compound.

In your own words state the law of constant composition. What does this suggest about the effectiveness of generic drugs?

What is meant by an aqueous solution? To what specific category of matter do aqueous solutions belong?

Prepare an expanded classification scheme of matter that includes all of the distinctions made in this chapter.

Indicate at least five regular chemistry patterns described in this chapter.

CHAPTER 3 PROPERTIES OF MATTER: OPPOSITES ATTRACT 103

23. What are the differences between the substances in each of the following pairs? a) COandCo 
b) SO3 and SO32-

24. The correct formula for a compound made from copper and oxygen is:
A. CuO B. Cu2O C. Cu2O3 D. Cu3O2 E. both A and B

25. One of the following formulas is incorrect. Write the correct formula for this compound and determine its correct name. 
A. Ba(OH)2 B. KMnO4 C. Na2O D. CaCl