chemistry unit exam #2

1 Calorie =

1kcal or 1000 calories

1000 calories =

1 Cal or 1kcal

exothermic

reaction that gives off heat energy(heat is a product)

endothermic

reaction that requires heat energy(heat is a reactant)

exergonic

reaction that gives off energy of any kind(energy of products<reactants)

endergonic

energy of some kind is required for the reaction(energy of reactants>products)

all exergonic reactions are always exothermic

false

what is thermal energy

energy associated with the motion of particles

what do all substances contain

potential energy

why do reactions occur

to convert the potential energy to kinetic energy so work can be done

what reaction requires energy to be added to it

endergonic

what is activation energy

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

how do you get the change in G value

energy of products - energy of reactants

what is a spontaneous reaction

negative change in G value, does not require energy from surroundings; energy of products < energy of reactants

what is a nonspontaneous reaction

positive change in G value, requires energy to be added from surroundings; energy of products > energy of reactants

what is the rate of reaction

determined by the amount of reactant used up or the amount of product formed over a certain period of time

what affects reaction rate

temperature, amount of reactant, and catalyst

what is a catalyst

a chemical or biological enzyme

what is a combustion reaction

a type of decomposition reaction; a molecule reacts with oxygen to produce carbon dioxide, water, and energy; ALWAYS EXOTHERMIC

what are the reactants in a combustion reaction

a molecule(alkane, alkene, or alkyne) with oxygen

what are the products in a combustion reaction

carbon dioxide, water, and energy

what type of addition reaction can alkynes do

hydrogenation, they cannot do hydration

what is being added in a hydrogenation reaction?

H2 molecule to an alkene or alkyne

what is the catalyst in a hydrogenation reaction

Pt or Pd

what is being added in a hydration reaction

H20 to an alkene

what is the catalyst for a hydration reaction

H+, acidic environment

what is markovnikov’s rule for hydration?

when H20 is added, the H attaches to the carbon that has more hydrogen atoms and the OH attaches to the carbon that has fewer hydrogen atoms

for markovnikov’s rule for hydration, what happens if there is no difference in the molecules?

then there will be two products; one with one combination and one with the other

what is the ratio for carbohydrates

Cn (H20)n ← so when there are 2 carbons, there will be 4 H’s and 2 O’s

what is considered an oligosaccharide

3-9 carbohydrate molecules

what is considered a polysaccharide

10 or more carbohydrate molecules

what are primary, secondary, or tertiary alcohols based on

the order of the carbon it is attached to

when naming molecules, what has to have the smallest number when a double bond and hydroxyl group is present

the double bond goes first

how do you know how many stereoisomers are in carbohydrates

look at the number of chiral carbons(carbon with 4 different groups bonded to it); number of steroisomers = 2 to the power of n, n=#of chiral carbons

what do horizontal lines on a chiral center represent

wedges

what do vertical lines on a chiral center represent

dashes

what group do you use to determine D or L isomers

the OH on the chiral carbon farthest from the carbonyl

what if an OH group is pointing to the right

D-isomer(down)

what if an OH group is pointing to the left

L-isomer(up)

what is a stereoisomer

molecule with the same formula, same attachment, but different spatial arrangement

what are enantiomers

two molecules that are mirror images of each other

what are diastereomers

stereoisomers that are not enantiomers

what are epimers

diastereomers that differ in just one chiral center

what is oxidation

gain of bonds to oxygen with less bonds to hydrogen

what is reduction

loss of bonds to oxygen with gain of bonds to hydrogen

what is a reducing agent

substance that drives reduction, undergoes oxidation

what is an oxidizing agent

substance that drives oxidation, undergoes reduction

can you oxidize a tertiary alcohol

nope

what can a secondary alcohol be oxidized to

ketone

what can a primary alcohol be oxidized to

with a mild oxidizing agent, it can be oxidized to an aldehyde; with a strong oxidizing agent, it can be oxidized to a carboxylic acid

what can a ketone be reduced to

a secondary alcohol

what can an aldehyde be reduced to

a primary alcohol

what are reducing sugars

sugars that can be oxidized

what does a positive test for benedict’s test for reducing sugars look like

bright red

what does a negative result for the benedict’s test look like

stays blue

how does Cu2+(benedict’s) work with a urinalysis

with a urinalysis, if the strip changes color, it indicates the presence of glucose/reducing sugar; more color change → more glucose present

what is a condensation reaction

when water is produced when two organic molecules react

what is a hydrolysis reaction

when water reacts with an organic molecule to split into two organic molecules

what can two alcohols be condensed into

ether molecule + water

what can an ether molecule + water turn into by hydrolysis

two alcohol molecules

what can an alcohol + carboxylic acid be condensed into

ester + water

what can an ester molecule + water become through hydrolysis

an alcohol + carboxylic acid

what can an amine and carboxylic acid be condensed into

an amide + water

what can an amide + water become through hydrolysis

amine + carboxylic acid

what is a glycosidic bond

forms when the OH group on the anomeric carbon of one monosaccharide reacts with an OH of another monosaccharide

what can glycosidic bonds be named

alpha(OH facing down) or beta(OH facing up); and either (1-4) or (1-6); you name the bond starting with carbon that is to the left, or carbon that is on top

whats the difference between starch and glycogen

starch is for plants while glycogen is for animals

where are carbohydrates on red blood cells

they are on the surface of red blood cells and that dictates blood types

what are polar groups

C-O, C double bond 0, O-H, N-H, C-N, C-X(halogen)

what are nonpolar groups

C-H, C-C

what are polar compounds

contains atleast one polar group; 4 or less carbons in carbon chain; more polar groups=more polar

what are nonpolar compounds

hydrocarbons; 1 polar group but 5 or more carbons in carbon chain

what is an attractive force

attraction of an electron-rish area of one compound with an electron-poor area of another compound

what is an intermolecular force

attraction between two molecules

what are the 5 kinds of attractive forces

london dispersion forces, dipole-dipole, hydrogen bonding, ion-diple, and ionic bonding

what are london dispersion forces

eneven distribution of electrons over the surface of a molecule results in partial positive end and partial negative end on the molecule; uneven distribution; present in all molecules but most important for nonpolar molecules; temporary; the bigger the molecule → more london forces

what is a dipole dipole

permanent uneven distribution of electrons caused by electronegativity difference; only present in polar molecules; partial negative end of one molecule is attracted to partial positive end of another

what is hydrogen bonding

interaction between H-bond donor and H-bond acceptor; NOT an actual bond, strong dipole-dipole interaction; partial positive charge on H and partial negative charge on N,O, or F; can occur between the same molecules, two different polar molecules; or even two parts of a single molecule(must have distance)

what is ion-dipole attraction

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

what is an ionic attraction

attraction between opposite charges of ions; salt bridges

do molecules that are far apart have strong intermolecular forces

no, forces that are farther apart have weak intermolecular forces; the strength of the force decreases with distance;

what happens when a substance is heated

the particles move faster and then particles are not held as tightly; molecules can’t establish intermolecular forces due to their spped

what happens when a substance is cooled

the particles move slower so particles are held more tightly together(can establish intermolecular forces)

what is the boiling point

when molecules have enough energy to change fron liquid to gas or gas to liquid

what is the melting point

when molecules have enough energy to change from a solid to a liquid and liquid to solid

do alkanes with a lesser number of carbons have high melting and boiling points?

no, alkanes with greater number of carbons have higher melting and boiling points

do straight chain alkanes have high boiling and melting points

yes, straight chain alkanes have greater melting and boiling points than branched alkanes with the same number of carbon(closer to each other for london forces)

what increases boiling and melting points

increasing intermolecular force strength because more energy is needed to separate molecules from each other

what is solubility

the maximum amount of a substance that can dissolve in a specified amount of water at a specific temperature; the ability of one substance to dissolve another

what is the solubility rule

like dissolves like; polar molecules dissolve with polar molecules, nonpolar molecules dissolve with nonpolar molecules

do oil and water mix

no, oil is polar and water is nonpolar

do sugar and water mix

yes, sugar is polar and water is polar

what is a hemiacetal bond

when the oxygen of the hydroxyl group bonds with the carbon in the carbonyl group; a carbon that is bonded with an ether group and a hydroxyl group; when a ring forms

what is an acetal carbon

when the two rings form/combine together; they from a carbon that is bonded to two groups of ethers

what is an anomeric carbom

the carbons that are double bonded to an o; dictate alpha and beta isomers; usually carbon 1

what are amphipathic molecules

contain a polar(hydrophilic) part and a nonpolar(hydrophobic) part; the hydrophilic part would project towards the water/solvent(anion); the hydrophobic part would avoid water and sandwich themselves on the inside

what is pressure

force exerted against a given area

what is boyle’s law

P1V1=P2V2; the volume of a fixed amount of gas at constant temperature is inversely proportional to the pressure of gas

how is boyle’s law applied to breathing

inhalation: the diaphragm contracts and moves down; volume of chest cavity increases, pressure decreases and external air rushes in to equalize the pressure

exhalation: the diaphragm relax and moves up; the volume of the chest cavity decreases, pressure increases, and air rushes out from lungs into atmosphere

what is charles’ law

V1/T1=V2/T2, volume of a fixed amount of gas at constant pressure is directly proportional to the absolute temperature of the gas