chem chap 11&13

Question 1

what is molarity

Answer 1

moles of solute/liters of solution (M)

Question 2

what is mass percent

Answer 2

mass of solute/mass of solution x100

Question 3

what is molality

Answer 3

moles of solute/kg of solvent (m)

Question 4

what is mole fraction

Answer 4

moles of a/total moles (Xa)

Question 5

what is normality

Answer 5

number of equivalents/liter of solution (N)

Question 6

explain normality

Answer 6

when you have multiple ions for every mole of a molecule
H2SO4 has two H+ ions for every mole of H2SO4 so 2eq/L

Question 7

what are the steps in solutions formation

Answer 7

1. the solute separates into individual components (expanding solute)
2. the intermolecular forces in the solvent are overcome to make room for the solute (expanding solvent)
3. solute and solvent interact to form the solution

Question 8

does the solute and solvent expanding require or release energy

Answer 8

require energy since overcoming the intermolecular forces takes energy (endothermic)

Question 9

does a solution forming absorb or release energy

Answer 9

release (exothermic)

Question 10

solutions form between similar compounds or different compounds

Answer 10

polar molecules form solutions with polar molecules
nonpolar molecules form solutions nonpolar molecules

Question 11

why do water and oil not mix

Answer 11

because ΔH1 and ΔH2 are large (exo) because oil is a large molecule and water has hydrogen bonding (lots of energy required)
ΔH3 is small because the molecules only minimally interact with eachother (LDF and induced dipole)
ΔH of solutions is large so no solution forms

Question 12

what factors affect solubility

Answer 12

polarity (structure)
pressure (henry’s law)
temperature

Question 13

what is henry’s law

Answer 13

C=kP where:
C is the molarity
k is a constant that varies
P is the partial pressure of the gas solute above the solution

Question 14

as the temperature of a gas increases the solubility

Answer 14

decreases (sulphates act as gases)

Question 15

why is the smallest gas the least soluble

Answer 15

because it is harder to get it into a solution

Question 16

why do nonideal solutions that react poorly have a positive deviation

Answer 16

because the poor reaction weakens the surface pressure (bonds are less strong) which allows for more vapor pressure = positive deviation

Question 17

why do nonideal solutions that react well have a negative deviation

Answer 17

because the good reaction strengthens the surface pressure (strong bonds) which allows for les vapor pressure = negative deviation

Question 18

nonideal solutions can have an ideal deviation, why

Answer 18

if they have similar structures and around the same amount of LDF they’ll act ideally

Question 19

what is osmotic pressure

Answer 19

the pressure that is present on the solution after osmosis

Question 20

what is an isotonic solution

Answer 20

solutions that have the same osmotic pressure

Question 21

how do you reverse osmosis

Answer 21

if you apply an external pressure greater than the osmotic pressure

Question 22

what is the vant hoff factor

Answer 22

moles of particles in solution/moles of solute dissolved (i)

Question 23

what are the adapted equations that include i

Answer 23

ΔT=iKm
Po=iMRT
Psoln=(mol of solv/(i x mol of solute) +mol of solv) x Psolv

Question 24

what does the equilibrium depend on

Answer 24

1. initial concentrations
2. relative energies of reactants&products
3. relative degree of organization of reactants&products

Question 25

K of reverse reaction

Answer 25

1/K

Question 26

what if the reaction is doubled what happens to K

Answer 26

reaction x n = K^n

Question 27

to combine reactions what do you do to the K

Answer 27

multiply the different K instead of adding them like with enthalpy

Question 28

what phases affect the K and which dont

Answer 28

aqueous and gas states affect K
solids and liquids do not

Question 29

what does a large K value signify

Answer 29

the equilibrium lies to the right

Question 30

what does a small K value signify

Answer 30

the equilibrium lies to the left

Question 31

what do you use Q for

Answer 31

to verify where the reactions lies

Question 32

if Q=K

Answer 32

system is in equilibrium

Question 33

if Q>K

Answer 33

too much product, will shift to the left

Question 34

if Q<K

Answer 34

too much reactant, will shift to the right

Question 35

how does the addition/removal of moles affect the equilibrium

Answer 35

shift away from the added
shift towards the removed
liquids and solid dont affect equilibrium

Question 36

how do you change the pressure of an equilibrium

Answer 36

add/remove a gaseous reactant or product
change the volume of the container

Question 37

how does a change in pressure affect the equilibrium

Answer 37

shift towards the side with the least moles if volume is decreased
shift towards the side with the most moles if volume is increased
only count aq/g moles

Question 38

how does a change in temperature affect the equilibrium

Answer 38

the energy available will be consumed
if energy is added the reaction will shift towards the side that doesnt consume energy (will consume energy in the process)

Question 39

how do you find the pressure of a gas

Answer 39

P=CRT where:
C is the molarity
R is 0.08206 (atm)
T is the temp. (K)

Question 40

how do you convert Kp to K and vice versa

Answer 40

Kp = K(RT)^Δn
where Δn is the (sum of the coefficients of gaseous products) - (sum of the coefficients of the gaseous reactants)