Exam 1 🫠

Question 1

% volume cocentration

Answer 1

1L solute
100L solution

Question 2

Mass percent solution

Answer 2

Mass of solute / mass of solution

Question 3

Molarity

Answer 3

Moles of solute / L of solution

Question 4

Molality

Answer 4

Moles of solute
Kg of solution

Why? Because volume can change in temp changes but Kg won’t

Question 5

(Strong) Electrolyte

Answer 5

Refers to an ion that dissociates completely In water thus allowing it to conduct electricity

Question 6

Dilution calculation formula

Answer 6

M1( concentration at the beginning) x V1=M2 (concentración at the end) V2

Question 7

Osmotic pressure Ideas!!!!

Answer 7

Solvent flow is driven by entropy!!!! Not intermolecular forces!!!! Will flow from dilute solution side to concentrated side or from low pie to high pie

WHY: as concentrated side increases in vol delta S will be large and positive do the fact that there was a high cencentration of solutes . Dilute side decreases in vol small amount or - delta S due to low concentration of solutes

If delta S total is greater then zero the process will happen spontaneously

Question 8

Ósmosis calculations

Answer 8

Pie = iCRT

C is molar concentration in molarity
R is 0.08206 Latm/molK
Answer or pie will be in atm
I is vant Hoffs factor is complete dissociate

To calc molar mass of pie solve for M and use variables given in the equation for mass and volume

Question 9

Henry’s law
Stuffs and calculations

Answer 9

Cgas = Kh Pg
Pg = partial pressure of said gas
Pi = Xi or molar ratio times P of gas in a perfect state in atms

Question 10

Kh

Answer 10

Constant in Henry law dependes greatly on temp

Major driver is entropy

As solids go to liquids they gain chaos so has a higher ^s

As gas goes to liquid ^s Is smaller because it looses chaos

^G = ^H - T^S

Question 11

Vant hoffs factor when to use

Answer 11

Osmotic pressure
Lower vapor pressure due to solutes that dissolve
Boiling/freezing temp changes

Non electrolyte I=1
Strong electrolyte will be # of ions in an ideal world and on the exam

Question 12

Vapor pressure calculations

Answer 12

Raults law

Ptot= x1Pvap1 + ….
P lowedered vap when is dissolved
Pvap = x solvent PVap of solvent

Question 13

Boiling elevation
Freezing depression calculations

Answer 13

Delta Tf = iKfm
Delta Tb= IKbm
m is for molality

Question 14

Solution vicab

Answer 14

Solute - what is dissolved
Solvent - what the solute is being dissolved in generally a liquid

Concentrated= relatively large amount of solute or greater then . 1 M

Dilute: not concentrated or low amount of solute to solution ratio

< .1M

Question 15

Ppm or ppb

Answer 15

Ppm
Solute in milligrams / kilogram of solute
1x10^6
Ppb

Solute in micrograms/ kilograms

1x10^9

Question 16

Clausius Clapeyron equation

Answer 16

Tin kelvin
Hvap in j/mol (given normally in kj)
R= 8.314J

Make sure units match
Check temps and vapor pressures
Make sure all units cancel out

Question 17

Raults law

Answer 17

The total vapor pressure of a SOLUTIOn depends on the vapor presser of each part mole fraction pure components

Question 18

Vapor pressure rules

Answer 18

High intermolecular forces = low pvap
High temp = higher pvap
SURFacr area has no effect

Question 19

When do liquids boil

Answer 19

When they reach or exceed the pressure of the atmosphere or 1atm/760 torrr

Question 20

Non ideal deviations from Raults law

Answer 20

PVap influenced by intermolecular forces

Negative pressure occurs when a compound is more attracted to another compound of its self

Positive change when experiences few molecular forces so bounces and is repelled more often

Question 21

Equations that are used to find molar mass and

Answer 21

Equations that are used to find molar mass and take into account particles and not just moles

Question 22

Distillation

Answer 22

Separate substances based off of a boiling point. Understanding the higher the VP the lower the bp
Which also indicates lower intermolecular forces

We can use Raults law to see vp and tell who will come out first

Question 23

Colligative properties

Answer 23

Become proficient with calculations
With : mole fractions/ molality/ freezing boiling/ raults law and osmosis
To solve for molecular mass grams over moles