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Chem 115 Exam 3
Question | Answer |
---|---|
Oil is predominantly made of ____ molecules | organic |
The simplest types of organic molecules are | hydrocarbons |
What is an isomer? | molecule with same molecular formula but different structures and therefore different physical properties |
What is the shape of hydrocarbons? | Nearly tetrahedral; bond angles close to 109.5; NOT FLAT |
What is catenation? | the ability to bond to itself |
What three factors is the chemical diversity of organic molecules a result of? | Heteroatoms, electron density and reactivity, and functional groups* |
Shows only bonds between carbons; carbons are at vertices | carbon skeleton formula |
Alkanes | Hydrocarbons with single bonds |
Alkenes | Hydrocarbons with double bonds |
Alkynes | Hydrocarbons with triple bonds |
Names of organic molecules: 1, 2, 3, 4, 5, 6 | meth, eth, prop, but, pent, hex |
What is a saturated hydrocarbon | Each carbon bonded to a max number of other atoms |
Contains carbon atom bonded to four different groups | Chiral |
What is an unsaturated hydrocarbon | carbon bonded to less than four max atoms each |
What's the difference between cis and trans | Cis = same side; trans = opposite sides of the bond |
What are very large organic molecules | polymers |
Three kinds of cyclic hydrocarbons | cycloalkane; cycloalkene; cyclic alkyne |
A very special cyclic alkene | Benzene (two resonance structures... but neither is correct because actual is a hybrid |
What is a constitutional isomer | same chemical formula but different arrangement |
What properties are different between isomers? | density, boiling point, melting point, etc. |
What is a combustion reaction | Add O2, produce CO2 and H2O |
What is oxidation | conversion of carbons in hydrocarbons to CO2; creating bonds to oxygen |
What is an alcohol | organic molecule with a C bonded to OH |
Double bonded O between two R groups | Ketone |
Double bonded O at the end of a chain | Aldehyde |
Carboxylic acid | double bonded O and OH group |
NH2 at the end of a carbon chain | amine |
N and double bonded O | amide (peptide) |
haloalkane | Carbon bonded to a halogen (CH3F)(C-X) |
O=C-O-C-R | ester |
C triple bonded to N | nitrile |
What provided important components for society including fuel and raw materials for production? | Oil |
Organic molecules have _________ shapes | 3-D |
Relative ability of bonded atom to attract shared e- | Electronegativity |
Trend of EN | increase right; decrease down |
Polar covalent bond | atoms with different EN bond |
Nonpolar covalent bond | atoms with equal shared EN |
What is the standard technique for figuring out functional groups in organic molecules | Infrared spectroscopy |
White light is | The mixture of all colors of light |
IR radiation is detected as _____; UV radiation is detected as _____ | heat; sunburn |
Absorption depends on _____ | Concentration |
A=elc... what law is this | Beer-Lambert |
When do molecules absorb IR | uneven distribution of charge in molecule (polar) or upon vibration (unequal charge distribution) |
c= | frequency*wavelength |
Pairs with higher bond energies will generally vibrate at a _____ frequency and have _____ wavelength IR absorption | higher; shorter |
Bond stretch types | symmetric (out); asymmetric(every other); bend (up and down) |
what to IR absorption frequencies depend on | mass of bonded atoms and strength of interaction between them |
energy= | h * frequency |
What happens when light interacts with matter | bonds break; vibration; rotation |
Name four greenhouse gases | CO2, N2O, H2O, and CFCs |
What is the purpose of the calibration plot in spectrophotometric analysis? | To determine molar absorption allowing you to calculate concentration and absorbency between values. |
molarity | moles/liters |
molality | moles/kg |
M1V1= | M2V2 |
Electronegativty goes towards what element? | Flourine |
No EN difference | nonpolar covalent |
0-0.4 EN difference | mostly covalent |
0.4-1.7 | polar covalent |
1.7-3.3 | mostly ionic |
An inbalance of charge over the molecule | molecular polarity |
ion-dipole force | ion + polar molecule (dipole) |
dipole-dipole force | polar + polar |
Hydrogen bond | H atom boned to F, N, or O |
induced dipole-dipole | have to have two difference substances |
ion induced dipole | ion + nonpolar |
force in all bonds | dispersion/ London |
What is miscible | soluble in each other in any proportion |
mixtures of elements that have metallic character | alloy |
Mass percent | (mass solute)/(mass solute + mass solvent) |
mole fraction (x) | (moles solute)/ (moles solute + moles solvent) |
mole percent | mole fraction X 100 |
intermolecular force strength in order of strongest to weakest | ion-dipole; h bond; dipole-dipole; ion-induced; dipole-induced; dispersion |
do lone pairs lead to a polar or nonpolar molecule | polar |
Is cis or trans more polar | cis |
What is the driving force that causes things to dissolve and potential for disorder | entropy |
What intermolecular forces are present in water? | h-bonding, dipole-dipole, and dispersion |
like dissolves like | like dissolves like |
A beaker contains 100 mL of salt water. If 100 mL of distilled water is added to the beaker, the number of moles of NaCl... | doesn't change!!! |
What does a colloid do | keeps things dissolved into one another |
Which is polar and nonpolar in a colloids head/tail? | polar head; nonpolar tail |
Which changes with temperature, molarity or molality? | molarity |
How do you determine dilution factor | M1V1=M2V2 |
higher boiling point = _____ bond | stronger |
What are the four main colligative properties | boiling point, freezing point, vapor pressure, and osmotic pressure |
what are colligative properties caused by | physical changes caused by difference between solute and pure solvent |
ions in solution; conducts electric current | electrolytes |
no ions in solution; don't conduct electric current | nonelectrolytes |
What effects colligative properties? | Number of solute particles; NOT what the solute is, just # |
what is vapor pressure | the equilibrium pressure of a vapor above its liquid |
How to calculate vapor pressure (P) | P of solvent = X of solvent * P original of solvent |
Vapor pressures are proportional to and dependent on what | Temperature |
What is the most accurate colligative property | Osmotic pressure |
Formula for boiling point elevation | Change in boiling temperature = bp elevation constant (k) * molality (m)... then add to original bp |
Formula for freezing point depression | Change in freezing temperature = fp depression constant (k) * molality (m)... then subtract from original bp |
More moles = ____ freezing point | lower |
semipermeable membrane | solvent can go through but solute can't |
causes solvent to move and drives concentration change | concentration gradient |
osmosis | passage of solvent through a semipermeable membrane separating two solutions of different concentration |
osmotic pressure ______ with number of solute particles | increases |
How to calculate osmotic pressure | =(Molarity)RT... has to be in L, Atm, n, and K |
difference between saturated and unsaturated | saturated: solid at room temp. ; unsaturated: liquid at room temp. |
The most abundant class of organic compounds found in living organisms | carbohydrates/polysaccharides |
Cellular membranes are made of a | phospholipid bilayer |
Cellular membranes have a _____ head and a _____ tail | polar/ionic head ; nonpolar tail |
Another word for polar and nonpolar | polar=hydrophyllic; nonpolar=hydrophobic |
Three parts to an amino acid | R group, amine, carboxylic acid |
Amino acids can have what three different kinds of side chains | polar; nonpolar; ionic |
Amino acids link together through a | peptide bond |
acid sequence determines _____ and _____ determines _____ | shape; shape; function |
Primary structure of proteins | sequence of amino acids |
Secondary structure of proteins | spatial arrangement of the polypeptide into shapes |
Which way to R groups face on amino acids | Stick outward and away |
Tertiary structure of proteins | overall 3-D shape of a polypeptide chain |
If a protein is in an aqueous environment, nonpolar pieces will face _____ | the middle |
What help to determine tertiary structure in proteins | intermolecular forces |
What is a fatty acid | lipid |
Quaternary structure of proteins | two or more polypeptide chains |
Fibrous proteins are | NOT soluble in water |
Proteins that are soluble in water are | globular |
3-D structure determines _____ | Function |
Proteins are _______ of amino acids | polymers |
Forces in a polypeptide chain | colvalent peptide bonds H-bonds between C=O of one and N-H of another Polar and ionic side chains with water through ion-dipole and H-bonds -SH ends of 2 cysteine side chains, s-s bond/ disulfide bridge |
Cysteine chains | have sulfur |
oppositly charged amine/carboxyl group ends form _________ | salt link/ion pair (creates bend) |
What type of interaction is primarily responsible for the secondary structures of proteins | Hydrogen Bonds! |