CHEM EXAM 3

ch 6-7

functional groups np vs polar

first 4 are np

LDF

all things have (np only have this)

dipole- diploe

polar have

hydorgen bond

strong must have H and it is attached to O,N, F

ion-dipole

attraction between an ion and a polar molecule.

LDF caused by

temp dipoles in atoms/molecules

Molecular size affects LDF

big size = increase LDF

branching affects LDF

if branching then low bp and low LDF

chain length affect BP

more on chain = higher bp

properties of water

high bp, high surface tension, low density when cold, flow against gravity

adhesion

sticks to walls = concave

cohesion

sticks to self = convex

capable of hydrogen bond

idk figure it out

miscible

mixible = p goes with p and np goes with np

make something soluble in water

add more polar groups

phase diagram

add it

Reactants

on left = start

Products

on right = end

Mol reactant to mol product

Use mol rato

Gram reactant to gram product

g - Molar mass - mol ratio - molar mass - g

Limiting reactant

Smallest mol ; ring by turning grams into mol

Theoretical yield

Use limit reactant ; find by turning mol to g

Percent yield

(Actual/ theoretical)x100

Why can percent yield be over 100

The thing(find word for it) can have excess water in it

Given molar mass, formula ; find percent comp by mass of one element

(Molar mass of element / total molar mass)x100

Given percent comp; find empirical formula

Assume you have 100g of whatever; turn % into g , turn to mol , divide by smallest number, if you get weird fraction number times by bottom

Do they have same empirical formula?

Smallest ratio so reduce by common denominator

Given empirical formula, molar mass; find molecular formula

(Molar mass/molar mass of EF)= n

(EF)n= MF

Combustion reaction

Hydro carbon + O2 —> CO2 + H2O

Given grams of sample, mass of water; find percent mass hydrogen

g water → molar mass of water → mol ratio → mol of H → molar mass of hydrogen→ (g hydrogen/sample g)x100