Chem Exam 2

Kinetic Energy

energy of motion, WORK

Potential Energy

stored energy, energy of the position of an object or the chemical composition of an object

Heat (thermal energy)

lost energy

a form of KE

energy associated with motion of particles

calories

1 Cal = 1 kcal = 1000 cal

Heat of reaction

• Exothermic: reaction that gives off heat energy (heat is a product) ex = hand warmer

• Endothermic: reaction that requires heat energy (heat is a reactant) ex = ice pack

Free Energy (G) change

• Exergonic: gives off energy of any kind (products < reactants) NEGATIVE delta G

• Endergonic: energy of some kind is required for the rxn (products > reactants) POSITIVE delta G

Activation Energy

the energy necessary to align reactants and cause them to collide productively

• always needs a little energy to be put in, in order to start the process to become products

Δ G

• Exergonic = - Δ G, a VERY negative Δ G indicates that most of the energy will be lost as heat

• Endergonic = + Δ G

• Larger Δ G: more free energy needs to be put in or will come out in the end

• Small Δ G: less free energy needs to be put in or will come out in the end

Spontaneous vs. Non-spontaneous

• Spontaneous rxs: DONT require energy from external source in order to occur (-Δ G) ex: moving with the current on a boat

• Non-spontaneous: REQUIRE energy from external source in order to occur (+Δ G) ex: moving against current, need paddling

Kinetics - Factors that affect reaction rate

• Temperature: increase temp, increases rate of rxn

• Amount of reactant: more reactants = more products

• Catalyst: increase rate of rxn through external factors, coordinates reactants to make more products

Combustion

• a type of decomposition rxn

• Alkane/Alkene/Alkyne + O2 —> CO2 + H2O + energy

• EX: energy in the body is produced by combustion of glucose

ADDITION RXNS (hydrogenation and hydration)

• Hydrogenation (for alkenes and alkynes): ADD HYDROGEN

• Hydration: acid catalyst is required (H+): ADD WATER

The H goes to the carbon w/more hydrogen atoms

The OH goes to the carbon w/fewer hydrogen atoms

Alkane

C-C

Alkene

C=C

Alkyne

carbon carbon triple bond

Ether

—O—

Aldehyde

Ketone

carboxylic acid

ester

Amine

N is on its OWN

• CH3—NH2

Amide

N is with CARBON

Carbohydrates

• Monosaccharide: 1

• Dissacharide: 2

• Oligosaccharide: 3-9

• Polysaccharide: 10-10,000

Primary Alcohol

Secondary Alcohol

Tertiary Alcohol

Chirality

• Chiral Carbon: has 4 different groups bonded to it

• Number of stereoisomers: 2^n (n = number of chiral centers in the molecule)

Isomers

• Enantiomer: mirror image

• Diastereomers: different everything, NOT same

• Anomer: only differs at anomeric carbon

• Epimer: differ at only ONE chiral center

D-Glucose

D-Galactose

D-Fructose

ketone version of glucose

Ring formation

• C6 ALWAYS ON TOP

• 6-membered ring = pyranose

• 5-membered ring = furanose

• Left = up

• Right = down

• C1 = ANOMERIC CARBON

• alpha = down

• beta = up

OXIDATION/REDUCTION rxns

• Oxidation: INCREASE OXYGEN, decrease hydrogens

• Reduction: INCREASE HYDROGEN, decrease oxygen

Oxidation

• primary alcohol —> aldehyde —> carboxylic acid

• secondary alcohol —> ketone

• CANT OXIDIZE TERTIARY ALCOHOL = NO RXN

Reduction

• aldehyde —> primary alcohol

• ketone —> secondary alcohol

Reducing Sugars

ONLY the carbonyl (top O=C-H) of a sugar is reduced

CONDENSATION AND HYDROLYSIS

• Condensation: Water is a product when two organic molecules react

• Hydrolysis: Wanter is a reactant with in an organic molecule split into two

CONDENSATION AND HYDROLYSIS (pt.2)

alcohol + alcohol = ether + H2O

alcohol + carbox. acid = ester + H2O

amine + carbox. acid = amide + H2O

Disaccharides

• a-D-glucose + D-glucose = maltose

• b-D-galactose + D-glucose = lactose

• a-D-glucose + b-D-fructose = sucrose (NOT A REDUCING SUGAR)

Blood

• AB = universal acceptor

• O = universal donor

• A = can receive A and O, donates to A and AB

• B = can receive from B and O, donates to B and AB

Polar vs. Nonpolar

• Polar = C-O, C=O, O-H, N-H, C-N, C-X (halogen)

• Nonpolar = C-H, C-C

• Polar compound: has at least 1 polar group, 4 or less carbons in carbon chain (1 polar group: 4 carbons in a chain)

• Nonpolar compound: 1 polar group but 5 or more carbons in a carbon chain

Polar Covalent Bonds

• Assign partial charges (S- and S+)

Attractive Forces

(weakest) London forces —> Dipole-dipole —> Hydrogen bonds —> Ion-dipole —> Ionic (strongest)

• strength depends on distance (far = weak, close = strong)

• DONT PLAY A ROLE IN GASES

London forces

• weakest force

• anything with mass + electrons has it MOST IMPORTANT FOR NON POLAR

• larger molecules = stronger LDF

• caused by momentary disturbance

Dipole-Dipole

• permanent partial charges distributed around bonds and their molecules

• stronger than LDF bc charges are permanent but still weak bc they can be disrupted by energy

Hydrogen Bonds

NEED TO HAVE DONOR AND ACCEPTOR

• H bond DONOR = H (H-N, H-O,H-X)

• H bond ACCEPTOR = N, O, X (with lone pairs)

• strong dipole-dipole attraction

• dependent on presence of two dipole groups one with partial + and the other with partial -

Ionic

• occurs between ionic charges in ionic compounds and partial charges in polar molecules

• attraction btwn opposite charges of ions

Solubility

• “like dissolves like”

• polar + polar = do mix

• nonpolar + nonpolar = do mix

Amphipathic molecules

• contain both polar and nonpolar regions

• Hydrophilic = polar, projects away from non polar and toward polar solvent

• Hyrophobic = nonpolar, comes from long hydrocarbon chain

• Micell = basis of soaps and detergents

Boyle’s Law

• pressure and volume

• Pi x Vi = Pf x Vi

• breathing example: chest cavity expands by rib and diaphragm muscles, volume increase —> pressure decrease so gas rushes in

when muscles relax, chest cavity decreases (volume decreases, pressure increases, gas flows out)

Charles’s Law

• Volume and temperature at constant pressure

• Vi/Ti = Vf/Tf

• Temp (°C) + 273.15 = Temp (K)

Fatty Acids

• Saturated = one double bond

• Monounsaturated = two double bonds (cis double bonds)

• Polyunsaturated = 2+ double bonds