Chemistry 161 Lab Final

standard deviation (x meaning avg)

[(x1-x)²+(x2-x)² / n-1 ]^1/2

RSD (rate of SD) (x meaning avg)

(SD/x) x 100

How do you determine the best order from a graph?

plots are closest to the central line

Endothermic rxn has an increase in both ______ and ______. (which statement is false: not exo)

temperature, solubility

what is the best indicator for a strong acid and weak base = pH of 5?

methyl orange

NaOH + CaCl2

Ca(OH)2, ppt

x/100 = 3.89/ 5.5 = x. solve for x

70.78

4 percent PVA + cross linking = __________

rigid structures

slime + HCl

break down

slime + borax

PVA

slime + NaOH

Reforms

Zero order on a graph

[A]

first order on a graph

ln[A]

second order on a graph

1/[A]

solubility

max amount of solute that can be dissolved in a given solvent

as temperature increases, solubility _____

increases

exothermic equation

solvent +solute —> solution +heat; heat of sol <0

endothermic

solvent + solute +heat —→ solution; heat of sol >0

polymer (PVA/g mol)

a substance composed of large molecules that consist of repeating chemical units called monomers that are bonded together in a chain like fashion

crosslinker

a molecule capable of strong attractive interactions with 2+ chains. it forms rigid structures.

calculate the length of a PVA strand that has 2 carbon atoms and 3 monomer units (1 carbon = 154 pm)

924

solvent

liquid dissolving substance

solute

substance being dissolved

how do you find change in freezing point? what does i and Kf mean?

Tf (solution) - Tf(solvent) = -iK(f) x molality

i = # of dissolved particles per molecule or formula unit of solute

Kf= freezing point depression constant

molality (m)

mols solute/ kg solvent; delta T/ -Kf

molar mass of solute

mass of solute/ kg solvent = mass of solute/ ( delta T/ -Kf x kg)

delta Tb/f = ______; how to find predicted?

Kb/f x Molarity; + actual BP/FP to get predicted

moles solute

molality x kg

Rate=

K[x]^m[x]^n

K(rate constant)=_____: what is A?

Ae^-Ea/RT

A- collision frequency factor

ln(K2/K1) =

-Ea/R (1/T2 - 1/T1)

how does low Ea impact collisions

increases collision effectiveness

how does temp increases impact collisions?

increases amount of collisions

what does a catalyst do to Ea?

decreases Ea

How does ionic strength impact collisions?

increases rate of collisions

how to find rate using change in concentration and temp?

delta [x] / delta t

find the rate order of

Rate = K[Br][NO]²

a(o)

starting angle of light rotation

a(infinity)

end angle of light rotation

optically active

chiral molecules rotate polarized

polarimeter

device that measures light angle rotations

sucrose

clockwise

glucose

counter clockwise

chiral molecules

meaning their mirror images are not superimposable. these rotate polarized light and are said to be optically active

sucrose is a chiral molecule, meaning…

mirror images are not super imposable