# CHEM 122 Lecture Notes - Lecture 5: Colligative Properties, Molar Mass, Osmosis

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CHEM NOTES

PRACTICE EXAM NOTES:

1. In PvT graphs, the compound with the largest i value is the lowest line….ie

the higher the i value the lower the PvT relationship.

2. colligative properties depend on the number of solute particles in a solution.

3. vapor pressure: moles x pressure

4. highest i = highest BP

5. osmosis: pure solvent diffuses through a membrane, solutes do not

6. osmotic pressure of blood is 7atm, so a BP of 7atm is required to prevent

osmosis if blood comes into contact w pure water across a membrane.

7. times the other ratio and divide by your ratio

8. half-life : T1/2=0.693/k

9. to ﬁnd the time required for compound to decompose use: Ln(A)= kxT

10. the number of half lives that are needed to get to e.g. 1/8 is what u multiply

the half life by. e.g. #23

11. a catalyst is a reactant of step 1 and product of step 2……an intermediate is

a product of step 1 and reactant of step 2

12. in a two step equation, the reactants of step 1 determine the order and rate

formula

13. In Arrhenius equation, smaller slope has smaller Ea

14. WHEN A and RR can be multiplied by same number ( e.g. 3) and give the

correct numbers, its 1st order

15. WHEN A and RR cannot be the above, and only produce the correct

numbers if A is multiplied by 3 and RR is multiplied by twice that of 3 ( therefore 9) then it

is 2nd order.

16. KNOW THE INTEGRATED RATE LAW EQUATIONS FOR 0,1,2

ORDER…..put the given conc in LnA, LnA0 is what you are trying to ﬁnd if they ask

whats the conc after X secs?

17. Forward Reaction is lower than REVERSE Reaction. transition state

energy is highest

review chapter 11 PAGES :

units of conc 54,55,59,61,67

solubility and henry’s law 73

colligative properties 80,83,98,108

uses of colligative properties 102,104,107

LAB HELP: WHAT IS THE MOLAR MASS OF AN UNKNOWN SUGAR IF A SOLUTION

PREPARED BY DISSOLVING 0.822G OF SUGAR IN 300ML OF SOLUTION HAS A

OSMOTIC PRESSURE OF 0.196 ATM AT 298K?

Π= “i” MRT R= 0.0821 atm/KxM

molar mass= g/mol= 0.822g/ 0.00240 = 342.5g/mol

0.196atm=(1)(moles/0.300L) (0.084) (298K)

moles= 0.00240

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