Solutions Flashcards

1
Q

solutions

A

a homogenous mixture of 2 or more substances

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2
Q

when do solutions form

A

they form when there is sufficient attraction between the solute and the solvent

solute-solvent interactions > solute-solute interaction and solvent-solvent interactions

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3
Q

water as a solvent

A

a polar molecule due to polar O-H bonds and bent shape

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4
Q

what does the expression “like dissolves like” mean

A

a solution will form if a polar solute is mixed in a polar solvent or a non polar solute is mixed in a non polar solvent

a solution will not form with a polar solute is mixed in a nonpolar solvent or vice versa

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5
Q

why is methanol soluble in water

A

it has a polar OH group to form hydrogen bonds with water

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6
Q

why are compounds such as iodine, oil, or grease insoluble in water

A

there are no attractions between the particles of a nonpolar solute and the polar solvent

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7
Q

the process of solubilization

A
  1. the intermolecular forces between solute molecules must be overcome.
  2. the intermolecular forces between solvent molecules must be overcome
  3. for the solvation process to take place, the energetic costs for the first two steps must be surpassed
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8
Q

electrolytes

A

dissolve in water; the process of dissociation separated them into ions forming solutions that conduct electricity

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9
Q

nonelectrolytes

A

do not separate into ions when dissolved in water. dissolve as molecules in water.

C12H22O11 (sucrose) –> C12H22O11 (solution of sucrose)

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10
Q

strong electrolyte

A

dissociate 100% in water producing positive and negative ions; can conduct an electric current strong enough to light a bulb

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11
Q

weak electrolyte

A

dissociates only slightly in water. form a solution with a few ions and mostly undissociated molecules [equilibrium]

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12
Q

degree of dissociation (α)

A

ration between the number of moles dissociated and the total number of moles of the compound

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13
Q

degree of dissociation for strong electrolytes

A

alpha = 1

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14
Q

degree of dissociation for nonelectrolytes

A

alpha= 0

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15
Q

gout

A

attacks of gout may occur when the concentration of uric acid in blood plasma exceeds its solubility of 7mg/100ml of plasma at 37 C

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16
Q

solubility

A

the maximum amount of solute that dissolves in a specific amount of solvent

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17
Q

what does solubility depend on

A

temperature

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18
Q

unsaturated solution

A

contain less than the maximum amount of solute

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19
Q

saturated solution

A

contain the maximum amount of solute that can dissolve; it has undissolved solute at the bottom of the container

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20
Q

categorise solute-solute interaction and solvent-solvent interactions

A

these interactions are of the weak type: dipole-dipole interactions, van der Waals contact

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21
Q

how are ionic compounds that are insoluble in water stabilised?

A

by strong solute-solute interactions

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22
Q

effect of temperature on solubility of gases

A

as temperature increases solubility of gases decreases

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23
Q

effect of temperature on solubility of solids

A

solubility of most solids increases as temperature increases

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24
Q

what happens when a saturated solution is carefully cooled?

A

it becomes a supersaturated solution because it contains more solute than the solubility allows

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25
henry's law
the solubility of a gas in a liquid is directly related to the pressure of that gas above the liquid.
26
Henry's law equation
C= k x p c= concentration of solute gas in liquid solvent p= pressure of gas above liquid
27
what happens when the pressure of a gas above a solution decreases
the solubility of that gas in the solution also decreases
28
what is the case of insoluble ionic compounds?
the ionic bonds are too strong for the polar water molecules to break
29
when are sulfates SO4 2- insoluble?
when combined with Ba 2+, Pb 2+, Ca 2+, Sr 2+ and Hg 2+
30
concentration of a solution equation
concentration of a solution= amount of solute/ amount of solution
31
mass percent (m/m)
mass of solute (g)/ mass of solute (g) + mass of solvent (g) x 100%
32
grams of solute in 100 grams of solution
mass percent (m/m) = grams of solute/ 100 grams of solution
33
volume percent (v/v)
volume of solute/volume of solution x 100
34
volume of solute in 100ml of solution
volume percent (v/v) = ml of solute/100ml of solution
35
mass/volume percent (m/v)
mass of solute/ volume of solution x 100%
36
mass of solute in 100ml of solution
mass/volume percent (m/v) = g of solute/ 100ml of solution
37
molarity
M = moles of solute/ liter of solution
38
equivalent (Eq)
the amount of electrolyte or an ion that provides 1 mole of electrical charge
39
how are the concentration of electrolytes in intravenous fluids expressed as
milliquivalent per liter (mEq/L) 1Eq= 1000mEq
40
how many mEq/L does a solution of 25mEq/L of Na+ and 4mEq/L have?
29mEq/L
41
IV bottle
an IV bottle contains NaCl. If the Na+ is 34 mEq/L, the Cl- is also mEq/L
42
dilution
in a dilution water is added. the volume of a solution increases. the concentration decreases
43
what happens when water is added to a concentrated solution
there is no change in number of particles. the solute particles spread out as the volume of the solution increases
44
dilution equation
c1v1= c2v2 v2= final volume: sum of the initial and added volume
45
properties of solutions
- transparent - do not separate - contain small particles, ions, or molecules that cannot be filtered and cannot be separated through semipermeable membranes
46
properties of colloids
- have medium-sized particles - can be separated by semipermeable membranes but not by filters eg god, cloud, dust
47
properties of suspensions
- heterogeneous, non-uniform mixtures - very large particles that settle out of solution - can be filtered - must be stirred to stay suspended
48
heterogeneous mixture
suspensions lead to precipitation where the solute's molecules cannot stay suspended in a solvent
49
what happens to the physical properties when a solute is added to water
1. vapor pressure above the solution decreases 2. The boiling point of the solution increases 3. The freezing point of the solution decreases
50
colligative properties
depend only on the concentration of solute particles in the solution
51
vapor pressure lowering
increasing the concentration of a non-volatile solute particle in the solution decreases the number of solvent particles at the surface of the solution. it prevents some of the solvent particles from leaving the solution
52
boiling point elevation
increase the concentration of nonvolatile solute particles in the solution raises the boiling point of the solution. more solute particles in the solution lower the vapor pressure: the solution boils at a higher temperature than the normal boiling point.
53
freezing point lowering
adding salt to an icy road when the temperature drops below freezing allows the particles of salt to mix with the water and lowers the freezing point of the ice
54
how does a solute that is a nonelectrolyte dissolve as
molecules
55
how does a solute that is a strong electrolyte dissolve as
ions
56
osmosis
water flows from a lower to a higher solute concentration across a semipermeable membrane
57
osmotic pressure
equal to the pressure that would prevent the flow of additional water into the more concentrated solution
58
when does osmotic pressure increase
as the number of dissolved particles in the solution increases
59
reverse osmosis
a pressure greater than the osmotic pressure is applied to a solution, forcing it through a purification membrane: water flows from an area of lower to higher water conc, leaving behind the molecules and ions in the solution
60
IV solutions
isotonic solutions: -exert the same osmotic pressure as body fluids such as RBCs - include a 5.0% m/v glucose or 0.90 m/v NaCl isotonic solution
61
hypotonic solution
lower concentration than RBCs and water flows into cells by osmosis: hemolysis
62
hypertonic solution
has higher solute concentration than RBCs it involves water going out of the cell by osmosis
63
dialysis
solvent and small solute particles pass through an artificial semipermeable membrane. large particles are retained inside. waste particles such as urea from blood are removed using hemodialysis.
64
Raoult's equation
P (solution) = X (mole fraction) x P (vapour pressure of the pure solvent) P (solution) = P (vapor pressure of the pure solvent) x n (moles of solvent)/ (n (moles of solvent) + n(moles of solute))