Chapter 5 - Molecules and Compounds

Question 1

Why is table salt considered to be a compound?

Answer 1

Sodium and Chlorine come together to make a compound

Question 2

What’s the major difference between a compound and mixture? (-how are they mixed?)

Answer 2

In a compound, elements are combined in Fixed, Definite proportions

Mixtures = whatever proportions

Question 3

What did Josepth Proust state about compounds?

Answer 3

Jo said that elements combine in fixed proportions to form compounds, in the Law of Constant Composition

Question 4

What do Chemical formulas normally list first?

Answer 4

The most metal

So table salt is NaCl and NOT ClNa

Question 5

Describe a polyatomic ion.

Answer 5

Polyatomic ions are groups of atoms that have a Charge associated with them

Question 6

Determine the number of each type of atom in the following:

Mg3(PO4)2

K2SO4

Al2(SO4)3

Answer 6

Ok

Question 7

Describe the different ways we categorize chemical formulas into 3 types:

Empirical
Molecular
Structural

Answer 7

Empirical - Simplest whole-number ratio of atoms of each element in a compound

Molecular - the ACTUAL number of atoms of each element in a molecule of the compound

Structural - Uses lines to represent chemical bonds to show how atoms in a molecule are connected to each other

Question 8

Represent Hydrogen Peroxide in Empirical, Molecular, and Structural formulas.

Answer 8

Empirical - HO

Molecular - H2O2

Structural - H-O-O-H

Question 9

What’s the difference between the Macroscopic world and the atomic and molecular world?

Answer 9

We can SEE water in the Macroscopic view

In an atomic and molecular world, we would see the atoms and molecules of H20

Question 10

T or F:

1. Pure substances may only be Elements
2. Elements may be either Atomic or Molecular
3. Compounds can only be Ionic

Answer 10

1. False - Pure substances may be Elements AND Compounds
2. True - Elements may be either Atomic or Molecular
3. False - Compounds can be Ionic AND Molecular

Question 11

______________ have single atoms as their basic units

Molecular elements normally exist as __________________ molecules as their base unit

__________________ are composed of two or more NONmetals

Answer 11

Atomic Elements have single atoms as their basic units

Molecular elements normally exist as Diatomic molecules - two atoms of that element bonded together - as their base unit

Molecular compounds are composed of two or more NONmetals

Question 12

Atomic Elements, Molecular Elements, Molecular Compounds:

Helium is an example of

Answer 12

Helium is an example of atomic element

Question 13

Do metal have the tendency to gain or lose electrons?

Answer 13

Metals have the tendency to LOSE Electrons - Non metals have the tendency to GAIN Electrons

Question 14

How are Ionic Compounds composed?

Answer 14

When a metal, which loses electrons, combines with a nonmetal, which gains electrons - opposites attract and one or more electrons become attracted to the nonmetal through the positive and negative ions

Question 15

What can we assume about a compound with both metal and nonmetal?

Answer 15

That it is ionic

Question 16

What is the Formula Unit and when do we use it?

Answer 16

The Formula Unit is the smallest electrically neutral collection of ions within an Ionic Compound

Question 17

How can we find the solution to this problem:

Classify each compound as ionic or molecular. If it is ionic, determine whether the metal forms only one type of ion or more than one type of ion.

Answer 17

We need to seperate the metal and nonmetal elements.

If it is a Molecular Element, there will be NO metal
If it is an Ionic Compound, there will be 1 Metal to 1 Non-metal