Unit 4

Question 1

Solutions:

Answer 1

homogenous mixtures of two or more substances

Question 2

Solvent

Answer 2

A compound of a solution that is present in the greatest amount

Question 3

Solute

Answer 3

Any component in a solution other than the solvent (i.e, the other ingredients in the mixture)

Question 4

How is a solution made?

Answer 4

By dissolving a solute in a solvent (solute is added to the solvent)

Question 5

How are solutions described qualitatively?

Answer 5

As concentrated or dilute

Question 6

Concentrated solutions…

Answer 6

have a large amount of solute compared to solvent

Question 7

Dilute solutions…

Answer 7

have a small amount of solute compared to solvent

Question 8

Saturated solution

Answer 8

a solution that contains the maximum concentration of a solute possible at a given temperature

Question 9

Unsaturated solution

Answer 9

• a solution that contains less than the maximum concentration of a solute possible at a given temperature
• can dissolve more of the solute into the solution

Question 10

Supersaturated solution:

Answer 10

a solution containing more than the maximum quantity of solute predicted to be soluble in a given volume of solution at a given temperature

Question 11

Concentration units

PPM

Answer 11

• grams of solute per million grams of solution
• =grams of solute/grams of solution (all times 10^6)
• OR mg of solute/kg of solution

Question 12

PPB

Answer 12

• grams of solute per billion grams of solution
• ppb=grams of solute/grams of solution (all times 10^9)
• OR micrograms of solute/kg of solution

Question 13

How to find the amount of solute (moles or grams) in a given voume of solution?

Answer 13

Use molarity

Question 14

Molarity formula

Answer 14

Molarity=# of moles of solute/# of L of solution

Question 15

molarity formula rearranged

number of moles solute=?

Answer 15

(molarity)(# liters of solution)

Question 16

Beer’s law

Answer 16

absorbance=molar absorptivity x path length x concentration of absorbing species

intensity of color can be used to measure concentrations

Question 17

A (in Beer’s law)

Answer 17

absorbance (amount of light absorbed by sample)

Question 18

E (in beer’s law)

Answer 18

molar absorptivity

Question 19

b (in beer’s law)

Answer 19

path length

Question 20

c (in beer’s law)

Answer 20

concentration of absorbing species

Question 21

Stock solution

Answer 21

a concentrated solution of a substance used to prepare solution of lower concentration

Question 22

Dilution

Answer 22

the process of lowering the concentration of a solution by adding more solvent

Question 23

Ionic Theory of Solutions

Answer 23

• proposed by Arrhenius to account for the electrical conductivity of water
• proposed that certain substances produce freely moving ions when they dissolve in water, and these ions conduct electric current in an aqueous solution

Question 24

Electrolytes

Answer 24

• An electrolye dissolves in water to give an electrically conducting solution
• most ionic solids dissolve in water
• ions in previously fixed states are free to move about, forming an electric current

Question 25

Strong electrolyte properties

Answer 25

* Total dissociation * Efficient conductivity * Includes strong acids, strong bases, and soluble salts

Question 26

Weak Electrolyte

Answer 26

* Partial dissociation * Slight conductivity * Weak acids and week bases

Question 27

Nonelectrolyte

Answer 27

* no dissociation * n/a conductivity * includes molecular compounds

Question 28

Ionic compounds in solution

Answer 28

* When an ionic compound is dissolved into solution, the molarity for each ion is based on how many ions there were in the salt * For example, in an aqueous solution that is 0.1M NaCl, your solution will have 0.1M Na+ ions and 0.1M Cl- ions based on the 1:1:1 mole ratio. * But if you have an aqueous solutio that is 0.1M Na2SO4, your solution will have 0.2M Na+ ions and 0.1M SO4 ions based on the 1:2:1 mole ratio.

Question 29

H+ ions strongly associated with water molecules form...

Answer 29

Hydronium ions (H30+)

Question 30

Acids

Answer 30

proton (H+ donors)

Question 31

Bases

Answer 31

Proton acceptors

Question 32

Neutralization

Answer 32

reaction that takes place when an acid reacts with a base a produces a solution of a salt in water

Question 33

Salt

Answer 33

* product of a neutralization reaction * made up of the cation of the base plus the anion of the acid

Question 34

amphiprotic

Answer 34

acts as acid or base (ex. water)

Question 35

Titration

Answer 35

an analytical method to determine the concentration of a solute in a sample by reacting it with a standard solution

Question 36

Standard solution

Answer 36

a solution of known concentration (also called the titrant)

Question 37

Equivalence point

Answer 37

point when moles of added titrant is stoichiomerically equivalent to moles of substance being analyzed

Question 38

End point

Answer 38

point reached when the indicator changes color

Question 39

Precipitation

Answer 39

combining an insoluable cation with an insoluable anion forms a precipitate

Question 40

Oxidation

Answer 40

loss of electrons

Question 41

reduction

Answer 41

gain of electrons

Question 42

Redox reactions

Answer 42

transfer of electrons