Week 2 Day 1

Question 1

solute

Answer 1

thing being dissolved

Question 2

solvent

Answer 2

thing doing the dissolving (often water)

Question 3

Solution

Answer 3

result of dissolving solute in solvent

Question 4

M

Answer 4

Molarity

moles of solute / liters of solution

*uses volume of solution not solvent

Question 5

density of water

Answer 5

1 g/ml at 4ºC, less at other temps

Question 6

m

Answer 6

Molality

moles of solute / kg of solvent

*molality uses mass of solvent

Question 7

percent by weight to volume (%w/v)

Answer 7

grams of solute / 100 ml of solution

Question 8

Percent by weight to weight (%w/w)

Answer 8

grams of solute / 100 g of solution

Question 9

ppm

Answer 9

(grams of solute/grams of solution) * 1,000,000

Question 10

1 equivalent (EQ)

Answer 10

1 mole of “reactivity”

Ex. Na⁺ = one equivalent

Ca⁺⁺ = two equivalents

Question 11

osmolarity

Answer 11

Concentration of a solution expressed as total number of solute particles per liter

ex: the osmolarity of a 1 M solution of NaCl is 2 Osm

Question 12

Solubility

Answer 12

the maximum amount of solute that will dissolve in a solvent

usually has units of mass/vol

Question 13

ÂH_solute

Answer 13

the energy needed to break up solute

usually > 0

Question 14

ÂH_solvent

Answer 14

the energy needed to break up solvent

usually > 0

Question 15

ÂH_mix

Answer 15

the energy we get back by the new arrangement

usually < 0

Question 16

ÂH_solution

Answer 16

total energy change during dissolving of solute

> 0 needs energy (endothermic)

< 0 gives off energy (exothermic)

Question 17

Effect of pressure on solubility

Answer 17

Increased pressure causes more gas to dissolve into solution

S = k_H * P_gas

k_H is specifec for each gas and is temperature dependent

Question 18

Effect of temperature on solubility

Answer 18

• increased temperature increases solubility of liquids and solids
• increased temperature decreases solubility of gases

Question 19

Colligative properties of solution

Answer 19

1. vapor pressure decreases with increasing solute concentration
2. boiling point increases with increasing solute concentration
3. freezing point decreases with increasing solute concentration
4. osmotic pressure increases with increasing solute concentration

Question 20

Vapor pressure

Answer 20

pressure of the vapor caused by the evaporation of a liquid above the sample of liquid in a closed container.

Question 21

Vapor pressure, Raoult’s law

Answer 21

P_s = X_s * Pº_s

P_s is vapor pressure exerted by solute

X_s is the mole fraction of s in the solution

P°_s is vapor pressure of pure S

Question 22

Osmotic pressure

Answer 22

water wants to move from high concentrations to low

Π = M * R * T

Π is osmotic pressure

M is molar concentration

R is universal gas constant

T is temperature

Question 23

Colloids

Answer 23

contain particles larger than molecules suspended in a solvent

Question 24

osmole

Answer 24

number of moles of solute that contribute to osmotic pressure

Question 25

dalton

Answer 25

atomic mass unit (amu)

Question 26

reverse osmosis

Answer 26

when the solvent goes from low concentration to high concentration b/c the hydrostatic pressure is \> osmotic pressure

Question 27

hydrostatic pressure

Answer 27

the pressure of the blood moving through the artery pushes the water out to the interstitial space. The osmotic pressure brings the water back into the blood vessel.

Question 28

miscible

Answer 28

Soluble. Able to be mixed to form a solution.

Question 29

solvation

Answer 29

water's negative end going toward cations and positive end going toward anions. inherently exothermic

Question 30

Vapor pressure equation

Answer 30

Log(P) = A + (B/T)

Question 31

surfactant

Answer 31

hydrophilic end that interacts with the water molecules and hydrophobid tail that prevents water molecules from interacting with each other. Reduces surface tension

Question 32

LaPlace's Law sphere

Answer 32

ÂP = (surface tension) \*(2/R)

Question 33

La Place's Law- cylinder

Answer 33

ÂP = (surface tension) \* (1/R)

Question 34

surface tension units

Answer 34

N/m

Question 35

Calusius-Clapeyron equation

Answer 35

used to estimate the vapor pressure at another temp if the VP at one temp is known and the enthalpy of vaporization is known. log (P) = A + B/T