chapter 10: Properties of solutions Flashcards
1
Q
what is a mixture
A
something that is composed of one or more pure substances
2
Q
What are some examples of mixtures
A
wood, milk, gasoline, champagne. steel, seawater, air
3
Q
what is a homogenous mixture
A
a something composed of one or more similar pure substances and it looks uniform throughout
4
Q
what is a solution
A
a homogenous mixture of 2 or more pure substances
5
Q
what is present in greater abundance in a solution
A
solvent
6
Q
what is the universal solvent
A
H2O/water
7
Q
what are some examples of solution
A
gases,liquids, and solids
8
Q
what is an aqueous solution
A
water is the solvent and we add a solid, liquid or gas
9
Q
what do the properties of solutions depend on
A
the structure of the molecules
10
Q
what is concentration
A
amount of solute dissolved in a given quantity of solvent or solution
11
Q
Molarity
A
M= moles of solute/ Liters of solution
12
Q
Molality
A
m = moles of solute / Kg of solvent
13
Q
what is temperature-dependent molarity or molality
A
molarity
14
Q
what are colligative property examples
A
vapor pressure lowering, boiling point elevation, freezing point depression, and osmotic pressure.
15
Q
what is a colligative property
A
properties that depend on the concentrations of solute or solvent
16
Q
what is giga
A
10^9
17
Q
what is mega
A
10^6
18
Q
what is kilo
A
10^3
19
Q
what is hecto
A
10^2
20
Q
what is deca
A
10^1
21
Q
what is deci
A
10^-1
22
Q
what is centi
A
10^-2
23
Q
what is milli
A
10^-3
24
Q
what is micro
A
10^-6
25
what is nano
10^-9
26
what is mass %
mass of solute / total mass solution
27
what is ppm (parts per million)
mass of component/ total mass x10^6
28
what is parts per billion
mass/ total mass x 10^9
29
what is mole fraction(X)
moles of solute/ total moles
30
if there is ppm or ppb then what does it indicate
mass fraction
31
what do you use to change molarity to molality
density
32
what is the density of water
1.00g/ml
33
1cm^3 =
1 mL
34
1000 mL = ?L
1
35
if given % of mass then what should you do
convert it to grams and find the other component using % (assume 100)
36
when is pressure the highest in a can
when the can is closed and not open and then the volume is the lowest because it is taking up most of the space
37
what happens to pressure and volume when a can is open
the pressure is going down and the volume is more because there is more space
38
like dissolves what
like
39
what is miscible
100% soluble
40
what is immiscible
always insoluble (NEVER soluble)
41
what is slightly miscible
soluble in some proportions
42
what is the weakest IMF
london dispersion
43
what is an IMf
- attractive force that exists among particles
44
what happens when you change the pressure
change the strength of attractions
45
what forces hold covalent bonds
intramolecular bonds (within the molecule)
46
larger distance means what
less energy to break; weaker
47
higher the normal boiling point
stronger the IMF; bc it takes more energy to break those bonds
48
what is a dipole-dipole force
exists in molecules that are polar and is WEAKER than ion-dipole forces
- stronger w/ increasing polarity
- polar mlcls have electron rich (-) regions and (+) regions that are not cancled out by the pull of electron density
49
what is a dipole
material w/ charged ends
50
what is a london dispersion force
nonpolar and polar
- weakest and most abundant
- instantaneous dipole
- induce dipole
51
what is an instantaneous dipole
- a nonpolar mlcl like H2 or o2 are symmetric w. their center of electron density
52
what is induced dipole
present in all molecules whether polar or nonpolar
53
what can hydrogen bond with in a hydrogen bond
HFON
54
what is an ion dipole
solution w/ ionic substances dissolved in a polar substance
| -strongest
55
what happens in steps 1-3 in a formation of a solution
step 1: endothermic to break down each reactant
step 2: endothermic to break down reactant
step 3: exothermic because we are forming a new substance
56
what is an endothermic process
total energy for breaking attractions is GREATER than energy RELEASED
57
what is an exothermic process
total energy for breaking attractions is LESS THAN energy RELEASED
58
what is enthalpy of hydration
combines the energy required to separate solvnt molecules + energy produced from solute-solvent interactions
59
what are the primary factors affecting solubility
- relative IMF forces between solute and solvent (stronger Imf = greater solubility)
- natural tendency of substances to mix( move toward a more dispersed and random state
60
what is preferred in solubility
disorder
| - example of removing the barrier
61
what is entropy
the amount of randomness in a system
| - lowers the energy
62
if like is dissolving like then what is the heat of solution
small, so the solution WILL form bc of increase in randomness
63
what happens to the heat of the solution when like dissolves dislike
large and positive and it wil prevent it from forming
64
in the example why would C5H12 dissolve CH3H3CH5OH
because it has a longer carbon chain even tho it has OH
65
what is the order of the forces
london< dipoledipole< hydrogen< ion dipole
66
what other factors affect solubility
-structure
temp
pressure
67
what determines polarity
molecular strucutre
68
nonpolar =
hydrophobic
69
polar =
hydrophillic
70
what happens if the length of carbon chain increases
1. affects solubility
| 2. as length of C increases then OH group become smaller
71
what are the 2 classes of vitamins
- fat soluble (adek) (hydrophobic)
| - water soluble (BC)( hydrophilic)
72
what is crystallization
solid begins to dissolve in a solvent and the solute particles become reattached to the solid
73
what is saturated
solution that is in equilibrium w/ undissolved solte
74
what is solubility
the amount of solute needed to form a saturated solution in a given quanityty
75
what is unsaturaed
less solute than what is needed
76
what is supersaturated
more solute than what is needed
| - unnatural
77
how does temp affect solid solute solubility
temp increases = solubility increases
- saturated = line
- unsatureaed= below
- supersaturated = above
78
what increases the solubility of gases
pressure
79
what is henrys law
```
relationship between pressure and solubility of a gas
c= KP
c= concentration
k = constant
p = pressure
```
80
how does temp affect gases
- solubility of gases in water decreases w/ increasing temp
- cold tap water is warmed and bubbles are seen
- carbonated drinks are more bubbly in fridge
81
what is vapor pressure
pressure exerted when equilibirum is reached
82
what is nonvolatile
no measureable vapor pressure
| salt
83
what is volatile
measureable vapor pressure
| ex: water
84
what happens when you add a nonvolatile solute to a solvent
it makes it hard for the solvent to escape, and it reduces the vapor pressure
85
if you have less moles what happens to the vapor pressure
pressure goes down as well
| smaller # of vapor molecules = lower vapor pressure
86
what is raoults law
extent to which a non volatile solute lowers the vapor pressure is proportional to the concentration
87
what is the formula for raoults law and what do each of the things mean
Psolution = XsolventPsolvent
Psolvent= pure partial pressure of the solvent
X solvent = mole fraction
88
what is raoults law all volatile
meaning both molecules are found in the vapor phase
89
what is the formula for raoults law all volatiel
Ptotal = Psolue+ Psolvent = XsolventPsolvent + XsolutePsolute
90
how do you find the mole fraction in an all volatile equation
Pbenzene/ P solution total (both molecules0
91
what is an ideal raoults solution
- colligative
- liquid-liquid solutions
- solute dilutes solvent
- Heat solution = 0
92
real solutions best approximate ideal behavior
- solute concentration is low
| - solute and solvent have similar IMFs
93
nonideal solution negative deviation characteristics
- solvent has STRONG affinity for the solute, vaporization is decreased
- observed vapor pressure is LOWER than predicted by raoults law
- occurs when Hsoln is large and negative(exothermic)
- example: acetone and water
94
nonideal solutoin- positive deviation characteristcs
- little to no affinity for the solute
- vaporization = increased
- observed vapor pressure is HIGHER than the predicted
- occurs when Heat soln is positive (endothermic)
ex: ethanol + hexane
95
what is the boiling point of water and what is boiling point elevation
100 degrees
| Bp elevation- normal bp of a liquid is the temp @ which its vapor pressure equals 1 atm
96
why is a higher temp needed for bp elevation
bc adding a nonvolatile solute lowers the vapor pressure so a higher temp is needed to obtain a vapor of 1 atm
- add more heat
97
what is boiling point elevation
- increase in boiling point relative to that of the pure solvent (Tb) is directly proportional to the MOLAL concentration
98
what does the change in Tb =
Kbm
99
what is the equation for boiling point elevation
BP solution= BP solvent (100 degrees) + Tb
100
what is freezing point depression
decrease in freezing point relative to that of the pure solvent
Tk is directly proportional to the molal concentration
101
what is a freezing point
temp @ which the the solid and liquid phases exist
- solute particles act as obstacles and disrupt solvent IMFs (entropy increases)
- entropy has to be overcomes to form a solid
102
what is the freezing point elevation equation
FP solution= Fp solvent(0 degrees) - Tf
103
what is a semipermeable membrane
allows some smaller particles to pass through but blocks larger particles
104
`what is osmosis
the flow of solvent from low concentration to high concentration
-natural
105
what is hypertonic
- high solute
- low solvent
- water moves out
106
hypotonic
- low solute
- high solvent
- water moves in (lysis or burst)
107
what is isotonic
equal concentrations moving in and out
108
what does osmotic pressure do
stops osmossis
109
what is the equation for osmotic pressure
MRT
- M = concentration
R = 0.08206
T= temperature in kelvin
110
what is reverse osmosis
pressure is GREATER than osmotic pressure and solvent flows from solution to pure solvent
move from high to low concentration
111
how are strong electrolyes and weak electrolytes different in solutions
strong shows more changes than weak
112
what is the van't hoff factor
the relationship between the moles of solute dissolved and the moles of particles in solution
113
how can you determine i
by noting the number of ions
ex. NaCl
i = 2
114
how can you determine i with a concentration
if they give you i then muliply it by the concentration to find the true value
greater i means stronger ex. greater i mean increase in BP
115
why is there a difference between the expected and observed colligative properties
because of electrostatic attractions
116
what do colligitive propertues of electrolytes involve
using the vant hoff equation
Tf- Kfmi
Tb = Kbmi
osmotic pressure = iMRT
