chem exam 3

molarity is

mol of solute / volume of solution

why is water good at dissolving things?

when a solute is dissolved in a solvent, that means the solution is more stable than when the two are separate

salt anions and cations would rather

be surrounded by water than not (soluble)

oil molecules would rather

be surrounded by themselves than H2O molecules (insoluable)

How do we know something dissolves?

substance gets distributed through the solvent

we physically see the substance gone

3 step process to dissolving

expand the solvent

break up the solute

combine them together

expand the solvent

solute particles need space between solvent molecules

costs little energy

break up the solute

particles in pure solute are surrounded by each other → must be separated

costs a lot of energy

combine them together

when a solvent surrounded solute, then intermolecular interactions are formed

releases energy

3 step process in dissolving salt in water

its hard to compress H2O, but you have to fit NaCl into it. push the H2O molecules apart to make room.

Salt is very compresses, you have to separate them from each other in order to dissolve (Na and Cl are separate)

everything fits together, Na and Cl go into the pockets in H2O

if expanding the solvent and breaking up the solute take less energy than it would to combine them

its soluble (costs less energy to dissolve)

if expanding the solvent and breaking up the solute take more energy than it would to combine them

its insoluble (costs more energy to dissolve)

dissolving sugar in water

when it dissolves in water, there are 30 Hydrogen bonds around 1 sucrose molecule

takes some energy to dissolve but you get the energy back when it’s release

strength of intermolecular interactions solute are same strength of intermolecular solvent when separate

anion

negatively charged ion

the electron of that element is not balanced

(element will usually have a - sign next to it)

why doesn’t oil dissolve in water?

can’t form strong intermolecular bonds

hydrocarbon

hydrogen doesn’t have any delta + or - making H2O have nothing to latch onto

oil has no hydrogen bonds, the H in water can’t bond to H or C in octane

hydrocarbon

molecule that just has hydrogen and carbon

non-polar

why is oil less dense when molecular weight is heavier?

carbon atom weighs less than hydrogen

H2O is heavier than C8H18

what’s another name for oil?

octane

polar molecules

polar bonds that don’t “cancel out”

non-polar molecules

polar bonds that cancel out

like-dissolves-like

polar (and ionic) solutes are soluable in polar solvents

non polar solutes are soluable in non polar solvents

Gramicydin A

antibiotic

how does gramicydin A work?

molecules coil up when put into water (non polar on the outside of coil, polar on inside)

non-polar parts poke holes into the cell wall of the bacteria

the inside is polar to help the flow of the ions

how does soap help get grease off?

grease is non polar. soap has both non polar and polar parts to it. the non polar part of soap gets stuck within the non polar grease. soap leaves the polar head on the outside. this tricks the water into thinking the grease is polar, which will make the water latch onto the soap, creating hydrogen bonds.

what to look out for and control in water

chlorine, lead and other heavy metals, mercury, hardness (Ca and Mg concentration), pH level, H2S (type of sulfur), viruses/micro-organisms

who/what regulates water?

EPA

clean water act

safe drinking water act

EPA

edits regulations on the amounts of substances in the water as we learned more about each substance and how it affects our health

MCLG

maximum containment level goal

its the goal of how much of each substance should be in the water

sand and gravel

act as a natural filter for water

as water trickles down into the ground from earth’s surface, the water goes through the sand and gravel, being filtered before entering into an aquifer

aquifer

underground reservoir of water

geological formation of porous material filled with water

1 × 10^15 gal of water trapped here

how do we make sure water is pure?

find a pure source

aeration

softening

filteration

disinfect & protect

finding a pure source

aquifer (MO has 15 wells that go through sand and gravel to pul water from aquifer)

aeration

buble air, or spray in air

removes any dissolved gasses from the water (CO2, H2S)

oxidizes and solidifies iron (dissolved iron turns into rust)

softening

add Ca(OH)2 → limestone

add Na2CO3 → baking soda

watr is still hard but only half as hard as it was

filteration

coal → sand → gravel

gets out some organic compounds

disinfect and protect

chlorine, Cl2 gas

we currently use Ca(OCl)2

ozone O3

ultraviolet light

chloramine

chlorine Cl2 gas

too dangerous

used as a chemical weapon in WW1

Ca(OCl)2

chlorine tablets

most reactive

gets rid of all micro-organisms

Chloramine

HOCl and NH3

buffs off the water but doesn’t have the bad stuff

decreases tri-halo methanes and cleans water

why do we leave some disinfectant in water when it leaves the plant?

the chemicals help the water remain clean

ozone O3

destroys micro-organisms

no Cl- residue

on the smaller scale, more expensive

UV light

destroys cell walls of bacteria

smaller scale, more expensive

nothing left in there to protect the water once it leaves the plant

which method(s) would a bottled water company most likely use to clean water? why?

UV radiation and Ozone

you can’t use these methods with municipal water like tap water because you need the chemicals to ensure it stays clean. bottled water is in a sealed tight container, once it’s in the water, there is not much that can happen to the water

two main ways of taking salt out of water

reverse osmosis

evaporation

osmosis

natural

water flows from least to most concentrated through the semi permeable membrane

reverse osmosis

the use of external water pressure reverses the flow

pushes salt water through the semi permeable membrane by pressure which takes out the salt, creating fresh water

semi permeable membrane

blocks the flow of ions in the water

evaporation

salt water is in this tank with a tilted ceiling. using green house gases, the H2O molecules evaporate and sit at the top of the ceiling. the NaCl stays at the bottom. the fresh evaporated H2O molecules slide down the slanted ceiling into the fresh water tank

what must be done for water to evaporate?

the bonds must break. H has to break from Cl and O has to break from Na

why does salt not evaporate with the H2O molecules?

sodium would rather stay with the 5 molecules of Na and Cl than leave with 1 H2O molecule

(sodium would rather stay with friends than leave with that one molecule)

medicine

substance that changes the way your body functions

characteristics of a drug

pain relief/fever

depression relief

kills virus/bacteria

hormone regulation

supplements

decongestants/allergies

evolution of aspirin

salicilin, then salicylic acid, then aspirin

modifying morpheme leads to

heroine

BBB

brain blood barrier

keeps bad things from reaching the brain

big polar molecules can’t get through

blood is

hydrophilic

brain is

hydrophobic

biomolecule

hormones, enzymes, protein

organic molecule

carbon containing

condensed structural formula

what’s bonded to the central atom will always be written on the right side

what’s written on the left is the central atoms, central atoms connect to each other

hydrogen can never

be a central atom

intermolecular condensed formula

CH3CH2OH

non intermolecular condensed formula

CH3OCH3

if it does not have an intermolecular bond

it is not soluable in water

lower bp because it takes less energy to break the bonds

if molecule has intermolecular bond

soluable in water

higher bp because it takes more energy to break those bonds

isomer

molecules having same chemical formula but different structure

atoms connected to different elements in the same compound

example of isomers

n-Octane vs. iso-Octane

line drawing

carbon carbon bonds

chemistry shorthand

carbon will never

contain LP

what elements are already implied in a line drawing?

H and C

writing out a line drawing

don’t have to draw C or H

only have to draw H if it connects to an element that is not C

have to draw ALL other elements

if a line drawing has no letters

it only contains C and H

its polar

you write out its geometry but don’t add LP

then you write a line drawing

you do not have to write out geometry but add LP

then you draw a Lewis Dot Structure

you have to draw double bonds

in both lewis dot structure and line drawings

hydroxyl

sometimes called alcohols

-OH

carboxylic acid

C has to be double bonded to O

formic acid is in this group

-COOH

ester

same thing as carboxylic acid except does not contain H

pineapple is an example

-COOR

amine

methylamine is an example

-NH2

does not have to have 2 H

amide

most proteins

-CONH2

does not have to have 2 H

chiral

when carbon is connected to 4 different things

carbon can’t be connected to itself for it to be chiral

aspirin

helps with aches, pains, fever

acetaminophen

helps with aches and headaches but not anti-inflammatory

what do aspirin, acetaminophen and ibuprofen all have in common?

all analgesies

all have phenyl rings (hexagon)

all have double bonds in the ring

have two groups coming off the ring

how to you determine the polarity between two atoms?

find the difference in the electronegativities

the further away the 2 elements are on the periodic table, the further away the electronegativity is which means its more polar

tell the difference between amide and amine

amide has NH connected to a C

amine does not have NH connected to a C

what’s an easy indicator if something is non-polar?

it has a lot of C-H bonds

NSAID

non-steroid anti-inflammatory drug

block production of molecules that ease pain and inflammation

what do enzymes do?

make pain and inflammation molecules

speed up redactions but are not consumed during process (are biocatalyst)

types of enzymes?

transferase

hydrolase

ligase

isomerase

transferase

add functional group to a molecule

like adding a hydroxyl

hydrolase

add water molecule to a molecule

in order do this, you must break a bond and then add the H2O

ligase

join two smaller molecules to make a bigger molecule

isomerase

rearranges the atoms in the molecule

biocatalyst

increase the rate of the reaction without being consumed

substrate

the reactant

fit into specific spot of the enzyme (the active site)

at the end of process, gets turned into something else

active site

where the reaction occurs

only fits closely related substrates

explain how an enzyme works

the substrate (what would specifically cause pain or inflammation) fits into the active sit of the enzyme. the tiny part of the substrate connecting the two substrates weakens and snaps. enzyme lets go of the broken substrate and does the process again