AP Chem Ch3

Question 1

What is a chemical formula?

Answer 1

A method for describing compositions of atoms (molecules, formula units, and/or compounds). There are various types such empirical formula (letters + ionic bonds), molecular “condensed” formula (letters + molecule), and molecular structural formula (2d bond structure + covalent bonds (molecule)).

Question 2

Water of hydration

Answer 2

The water molecules that are found in crystalline structures (i.e., the hydrates).

Question 3

Crystal

Answer 3

A periodic arrangement of atoms (or molecules).

Question 4

Hydrates

Answer 4

Compounds with “trapped” water molecules.

Question 5

How is a hydrate indicated in a formula?

Answer 5

A dot.

Question 6

Prefix for ‘4’

Answer 6

Tetra

Question 7

Prefix for ‘7’

Answer 7

hepta

Question 8

Prefix for ‘9’

Answer 8

nona

Question 9

Aqueous

Answer 9

Of water, typically referring to a solvent.

Question 10

Why do equations need to be balanced?

Answer 10

Law of conservation of matter

Question 11

Coefficients

Answer 11

A multiplier

Question 12

Why can’t formulas be altered in an equation?

Answer 12

The equation is the given (by who?). Think of the pigments - you wanted a certain outcome.

Question 13

Why can’t the subscripts be altered in an equation?

Answer 13

It would change the molecules involved.

Question 14

Neutralization reaction

Answer 14

A specific type of double replacement reaction where the two reactants are pairs of acid + base. The products are salt and water.

Question 15

What determines a substances pH?

Answer 15

How many free H+ atoms there are (these result from hydrogen bonds overpowering covalent bonds with H2O).

Question 16

Formation reaction

Answer 16

Same as a synthesis reaction but the product must have a coefficient of one.

Question 17

Addition reaction

Answer 17

Similar to a synthesis reaction except the molecules rather than elements are synthesized (this seems to be the case at least).

Question 18

Net ionic reaction

Answer 18

An ionic reaction in aqueous solution. This typically results in one ionic substance from each group to react (with the other in the pair being a “spectator” ion).

Question 19

Half-reaction

Answer 19

Half of the redox process (either oxidation or reduction).

Question 20

Oxidation-reduction reactions (redox reaction)

Answer 20

A reaction where electron(s) are transferred.

Question 21

Reduction

Answer 21

Gain of electrons (looses positive charge)

Question 22

Oxidation

Answer 22

Loss of electrons.

Question 23

Representative elements

Answer 23

Elements in the s & p blocks. They have regular properties and tend to follow uniform principles.

Question 24

What elements tend to form cations?

Answer 24

Representative metals.

Question 25

What elements tend to form anions?

Answer 25

Representative non-metals.

Question 26

Typical electron configuration of transition metals and why it's helpful.

Answer 26

Increasing by principle number. It helps to deduce the typical ions formed by the metal.

Question 27

Polyatomic ion

Answer 27

Charged groups of atoms that are highly stable and tend to act as a unit in chemical reactions.

Question 28

Pg 142, Table 3.3 of polyatomic ions

Answer 28

XX

Question 29

Law of electroneutrality

Answer 29

Compounds must have neutral charge (note that polyatomic ions are technical compounds but are not considered here).

Question 30

How to balance an ionic reaction

Answer 30

Bring the superscripts down as coefficients on the opposite reactant.

Question 31

What types of elements are involved in ionic bonds?

Answer 31

Metal and non-metal

Question 32

Naming with ions

Answer 32

1. Cation before anion 2. Cations name is used as is, with numerals to indicate charge if it can have different charges. 3. Monatomic anions are prefixed with '-ide.' Polyatomic are unique.

Question 33

What happens to most ions in water?

Answer 33

They dissolve and separate into the cations and anions.

Question 34

Solubility rules

Answer 34

1. Compounds containing sodium or potassium cations or ammonium ions are soluble 2. Compounds containing nitrate are soluble.

Question 35

Driving forces that determine if a double-replacement will occur.

Answer 35

1. Water is a strong driving force - if water is a product, it is very likely that a double-replacement is occurring. 2. Formation of a precipitate (insoluble compound) is another indicator of a driving force. 3. The formation of a covalent compound from an ionic reaction - many times in the form of organic acids or gases).

Question 36

Net Ionic Equations

Answer 36

An equation that cancels out the "spectator" ions. See the link for how - http://www.occc.edu/kmbailey/Chem1115Tutorials/Net_Ionic_Eqns.htm

Question 37

Spectator ions

Answer 37

Ions that are a reactant and product of a reaction but don't undergo any change. For instance, they start in an aqueous solution as single ions and end as single ions.

Question 38

What is a single replacement reaction between?

Answer 38

An element and an ionic compound which then forms a new element and ionic compound.

Question 39

Two types of single replacement reactions

Answer 39

1. Metal element reactant becomes a cation product | 2. Nonmetal element reactant becomes an anion product.