TEST 2

Question 1

electrolyte

Answer 1

something that breaks down in water to form ions. strong if completely breaks down and weak if only breaks into a few.

Question 2

non-electrolyte

Answer 2

dissolve to form neutral molecules. dont conduct electricity

Question 3

are salts soluble

Answer 3

some soluble, some not

Question 4

are soluble salts completely soluble or not?

Answer 4

they are completely soluble. So they are strong electrolytes

Question 5

how do we know if a salt is soluble?

Answer 5

by checking the solubility table

Question 6

are ions soluble?

Answer 6

yes. always. bc they are charged and water is polar

Question 7

precipitation reaction

Answer 7

reaction b/w two aqueous solutions that yields one solid product. this happens when one of the products is an insoluble salt

Question 8

molecular equation

Answer 8

shows neutral formula for each compound in aq reaction as if they existed as molecules

Question 9

ionic equation

Answer 9

in solutions containing soluble ionic compounds the dissolved substances are present as ions so we include this info in the equation. make sure you move the subscripts!!

Question 10

A precipitation reaction is

Answer 10

one in which dissolved substances react to form one (or more) solid products. Many reactions of this type involve the exchange of ions between ionic compounds in aqueous solution and are sometimes referred to as double displacement, double replacement, or metathesis reactions. These reactions are common in nature and are responsible for the formation of coral reefs in ocean waters and kidney stones in animals. They are used widely in industry for the production of a number of commodity and specialty chemicals. Precipitation reactions also play a central role in many chemical analysis techniques, including spot tests used to identify metal ions and gravimetric methods for determining the composition of matter

Question 11

solubility

Answer 11

The extent to which a substance may be dissolved in water, or any solvent/ the maximum concentration of a substance that can be achieved under specified conditions.

Question 12

soluble substances

Answer 12

Substances with relatively large solubilities

Question 13

insoluble substances

Answer 13

Substances with relatively low solubilities are said to be insoluble, and these are the substances that readily precipitate from solution. A substance will precipitate when solution conditions are such that its concentration exceeds its solubility.

Question 14

net ionic equation

Answer 14

ionic eq with spectator ions cancelled out.

Question 15

spectator ions

Answer 15

ions that don’t undergo a change from a rxn

Question 16

when is there no rxn

Answer 16

if none of the potential products are insoluble no reaction occurs.

Question 17

acid-base reaction

Answer 17

a reaction in which a hydrogen ion, H+, is transferred from one chemical species to another.

Question 18

acid

Answer 18

a substance that will dissolve in water to yield hydronium ions, H3O+

Question 19

A base

Answer 19

a substance that will dissolve in water to yield hydroxide ions, OH−. The most common bases are ionic compounds composed of alkali or alkaline earth metal cations (groups 1 and 2) combined with the hydroxide ion. previously, these compounds do not react chemically with water; instead, they dissolve and dissociate, releasing hydroxide ions directly into the solution.

Question 20

neutralization reaction

Answer 20

A neutralization reaction is a specific type of acid-base reaction in which the reactants are an acid and a base (but not water), and the products are often a salt and water

Question 21

oxidation

Answer 21

loss of electrons

Question 22

reduction

Answer 22

gain of electrons

Question 23

oxidizing agent

Answer 23

the one thats reduced

Question 24

reducing agent

Answer 24

the one thats oxidized

Question 25

The oxidation number of an atom in an elemental substance is

Answer 25

zero.

Question 26

The oxidation number of a monatomic ion is

Answer 26

equal to the ion’s charge.

Question 27

Oxidation number for Hydrogen:

Answer 27

+1 when combined with nonmetals, −1 when combined with metals

Question 28

Oxidation number for Oxygen:

Answer 28

−2 in most compounds, sometimes −1 (so-called peroxides, O22−),O22−), very rarely −12−12 (so-called superoxides, O2−),O2−), positive values when combined with F (values vary)

Question 29

Oxidation number for Halogens:

Answer 29

−1 for F always, −1 for other halogens except when combined with oxygen or other halogens (positive oxidation numbers in these cases, varying values)

Question 30

The sum of oxidation numbers for all atoms in a molecule or polyatomic ion equals

Answer 30

the charge on the molecule or ion.

Question 31

Oxidation-reduction (redox) reactions are

Answer 31

those in which one or more elements involved undergo a change in oxidation number.

Question 32

Single-displacement (replacement) reactions are

Answer 32

redox reactions in which an ion in solution is displaced (or replaced) via the oxidation of a metallic element. Metallic elements may also be oxidized by solutions of other metal salts

Question 33

Balancing Redox Reactions via the Half-Reaction Method

Answer 33

1. Write the two half-reactions representing the redox process.
2. Balance all elements except oxygen and hydrogen.
3. Balance oxygen atoms by adding H2O molecules.
4. Balance hydrogen atoms by adding H+ ions.
5. Balance charge by adding electrons.
6. If necessary, multiply each half-reaction’s coefficients by the smallest possible integers to yield equal numbers of electrons in each.
7. Add the balanced half-reactions together and simplify by removing species that appear on both sides of the equation.
8. For reactions occurring in basic media (excess hydroxide ions), carry out these additional steps:

Add OH− ions to both sides of the equation in numbers equal to the number of H+ ions.
On the side of the equation containing both H+ and OH− ions, combine these ions to yield water molecules.
Simplify the equation by removing any redundant water molecules.
9. Finally, check to see that both the number of atoms and the total charges1 are balanced.