Module Three - Chemical Reactions

Question 1

What is Avogadro’s number?

Answer 1

6.022xE23

Question 2

Aqueous (aq) mean that…

Answer 2

we have a substance thats dissolved in water.

Question 3

Solution are defined as…

Answer 3

a uniform mixture of two or more pure substances.

Question 4

What are precipitation reactions?

Answer 4

When two aqueous solutions are mixed to form an insoluble product. A precipitate forms if either of the two reactants are insoluble. If both possible products are soluble, no reaction occurs (like with cacl2 and kno3).

Question 5

What is the solubility pattern for NH4+ and alkali metal ions?

Answer 5

They are always soluble.

Question 6

Whats the solubility pattern for CH3COO- and NO3-?

Answer 6

They are always soluble.

Question 7

Whats the solubility pattern for Br-. Cl-, and I-?

Answer 7

Always soluble except, Ag+, Hb2+, and Pb2+.

Question 8

Whats the solubility pattern for CO32- and PO43-?

Answer 8

Usually insoluble.

Question 9

What is an electrolyte?

Answer 9

Any substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water.

Question 10

What is an acid-base reaction?

Answer 10

When a proton (a hydrogen ion, H+) is transferred from one chemical to another.

Question 11

What is an acid?

Answer 11

A chemical that produces H3O+ and an anion when dissolved in water. Acids are the proton donors. (For example, HCL produces H3O+ and Cl-).

Question 12

What is a base?

Answer 12

A chemical that generates OH- and a cation. Bases are the proton acceptors. (NH3 makes OH- and NH4+ in water)

Question 13

What is the difference between strong and weak acids?

Answer 13

Strong acids completely ionize in water. HCL is a strong acid, and after reacting, essentially no HCL molecules remain in the water.

Question 14

What are the six strong acids?

Answer 14

HCl, HBr, HI, H2SO4, HNO3, and HClO4.

Question 15

What are the six strong bases?

Answer 15

LiOH, NaOH, KOH, Ca(OH)2, Sr(OH)2, and Ba(OH)2.

Question 16

What are the three weak acids?

Answer 16

CH3COOH, H2CO3, and H3PO4.

Question 17

What is the one weak base?

Answer 17

NH3.

Question 18

What is a neutralization reaction?

Answer 18

A special kind of acid-base reaction, that results in a salt and H2O.

Question 19

What is a gas-forming reaction?

Answer 19

When a solid alkali metal is added to water OR when an acid is added to solid metal, the products are aqueous salt, hydrogen gas, and energy.

Question 20

What is the gas-forming rule with metal carbonates and acid?

Answer 20

Metal carbonates and acid react to form aqueous salt, water, and carbon dioxide gas.

Question 21

What is the gas-forming rule with metal sulfites and acid?

Answer 21

Metal sulfites and acid react to form aqueous salt, water, and sulfur dioxide gas.

Question 22

What is the gas-forming rule with metal sulfides and acid?

Answer 22

Metal sulfides and acid react to form aqueous salt and hydrogen sulfide gas. Notice how this one doesnt have water as a product!

Question 23

What does it mean when we write NaCl(aq)?

Answer 23

The solution contains aqueous sodium ions and aqueous chloride ions freely moving in the solution.

Question 24

What is the difference between strong and weak electrolytes?

Answer 24

A strong electrolyte is a compound that completely dissociates into ions when it is in an aqueous solution. Weak ones dissociate only partially.

Question 25

Why do ionic compounds conduct electricity when dissolved in solution?

Answer 25

Because their cations and anions can move freely in the solution.

Question 26

What is a spectator ion?

Answer 26

Any ion present in the but not involved directly in a reaction.

Question 27

What is a net ionic equation?

Answer 27

An equation that includes only the symbols or formulas of ions or molecules.

Question 28

What does Q1 and Q2 stand for?

Answer 28

Q1 is the charge on the cation and Q2 is the charge on the anion. D stands for the distance between the atoms in pm.

Question 29

What is the difference between ionic and covalent compounds?

Answer 29

Ionic compounds completely transfer electrons whereas covalent compounds share them.

Question 30

What are the Ox-Redox rules?

Answer 30

Atoms in a pure elemt have the ox number of 0.
Monatomic ions have the ox number equal to the charge.
When with another element, F always has the ox number of -1.
The ox number of H is +1 in most compounds, but is -1 with alkali metals.
Oxygen is -2, except when with fluorine (-1) or in peroxides (-1).
Cl, Br, and I are -1 when with O or F.

Question 31

What is an oxidation-reduction reaction?

Answer 31

When electrons are transferred from one reactant atom, molecule, or ion to another.

Question 32

What is the difference between oxidation and reduction?

Answer 32

Oxidation loses electrons, whereas redox gains them.

Question 33

Why do salts dissolve in water?

Answer 33

Because solvation energy, or ion-water attractions, are stronger than lattice attractions, or the ion-ion attractions that keep them together. The more the strength of lattice attractions, the more likely they are to be insoluble.

Question 34

What is the difference between H3O+ and H+?

Answer 34

Nothing. They’re the same thing.