biochem exam 1

What happens to energy in an endothermic process?

Energy is absorbed.

what happens to energy in an exothermic process?

energy is released

How do you interpret the value of the reaction energy in a chemical reaction?

A positive value indicates an endothermic reaction, where energy is absorbed; a negative value indicates an exothermic reaction, where energy is released.

What does an energy diagram for an endothermic reaction look like?

The energy diagram shows reactants at a lower energy level, with a peak representing the transition state at a higher energy level, and products at a higher energy level than the reactants, indicating energy absorption.

What does an energy diagram for an exothermic reaction look like?

The energy diagram shows reactants at a higher energy level, with a peak representing the transition state, and products at a lower energy level than the reactants, indicating energy release.

difference between ionic and covalent compound

ionic compounds formula metal+nonmetal, metal+ polyatomic ion, NH4 + anion. covalent compounds don’t start with metals or NH4

ammonium ion

NH4+

carbonate ion

CO3 (-2)

Nitrate ion

NO3 (-1)

sulfate ion

SO4 (-2)

phosphate ion

PO4 (-3)

hydroxide ion

OH(-1)

Formula for ionic compounds

cations first then anions

when to specify the number of elements in a compound

only for covalent

polar bonds

when 2 atoms in a bond have different electronegativity electrons are shared UNEVENLY, partial positive and negative charge

nonpolar bonds

when two atoms in a bond have the same electronegativities electrons are shared EQUALLY, no parital negative are positive charge

which elements generally make a polar molecule and why?

F,O,N because they are the most electronegative

in general which elements make a nonpolar molecule?

C,H

Classify polar and non polar molecules

add F+O+N then multiply by 3 this is polar score, Count the number of C atoms for non polar score. whichever is bigger that’ll be the molecule.

solids

individual particles are in fixed position, vibrate, define volume, shape

liquids

close contact, glide and slide, definite volume, indefinite shape

gas

particles of a substance are operate from each other and move about randomly in space, indefinite shape and volumes

solid to liquid

melting/fusion endothermic

liquid to gas

vaporazition/boiling endothermic

liquid to soil

freezing, exothermic

gas to liquid

condensation, exothermic

Explain and predict trends in melting point and boiling point.

larger molecules stronger forces and higher bp and mp and stronger forces higher bp and mp

water soluble ionic compounds

generally charge of -1 or +1 predict water soluble

covalent compounds water soluble and insoluble

covalent compounds are soluble because water is polar, insoluble water compounds won’t dissolve in water because they are non polar . Use F,ON X3 for polar score and add all C atoms for non polar score

electrolyte vs nonelctrolyte

electrolytes ionize when dissolved in water non electrolytes don’t they conduct electricity non electrolytes don’t, all ionic compounds and all acid and bases are electrolytes. nonelectrolytes are covalent compounds except for acid and bases

molarity

moles of solute per Liter of solution (M/L)

weight percent

the number of grams of dissolved solute per 100mL solution (g/100mL)

determine how many particles

1= non electrolyte, 2 or more = electrolyte ex. C₆H₁₂O₆ 1= non electrolyte, Mg₃(PO₄)₂ 5= electrolyte

osmolarity

total moles of all dissolved solutes per L solution. M x # of total dissolved particles ( the # depends on if the solute is electrolyte or non electrolyte)

formula for acids

H + something or something + COOH

formula for bases

metal + OH^- or NH₄ + OH^-, or covalent + N, not a base CH₃OH and CH₃CH₂OH

formula for salt

metal + anything not OH^- or NH₄ + anything not OH^-

hypotonic solution

< 0.2 Osm (mOsm), water flows in the cell, swell hemolyze

isotonic

0.2-0.4Osm (200-400 mOsm), no osmosis occurs, no effect on red blood cells

hypertonic

> 0.4Osm water flows out of the cell, cell shrinks and may shrivel, crenateNaCl

NaCl

isotoinc weight percent 0.9%

glucose C₆H12O₆

5% isotonic weight percent

acidic solutions

<7, some salts+ H₂O=acidic solution

neutral solution

pH=7, some salts and water equal neutral

basic solutions

pH>7, some salts + water= basic solution

define acid

any substance which donates an H⁺

define base

any substance which accepts and H⁺

neutralization reaction

acid + base = salt + water. ex 2 HCL + Ca(OH)₂= 2 H₂O + CaCl₂

which would be lower pH 0.1M NaOH or 0.1M HCL

0.1M HCL

Buffer

maintains about a constant pH even if you add a little acid or base

C₂H_{6, complete notation, condensed notation,, skeleton notation, and Line angle}

CH₃CH₃ or CH₃-CH_3, C-C, line angle must be three or more

line angle

there is a C at every bend and every end

hydrocarbon alkane

bond between C and H only single bond 0 C AND O BONDS

hydrocarbon alkene

double bond between C and H only 0BONDS C and O

alcohol

single bond C to OH R-OH 1 BOND C AND O

aldehyde

R-CHO carbon double bond O with H 2 BONDS C AND O

ketone

carbon double bond to O without H 2 BONDS C AND O

carboxylic acid

R-COOH carbon double bond to O and single bond OH 3 BONDS C AND O

carboxylic ester

Carbon double bond to O and single to O and C 3 BONDS C AND O

how to classify an alcohol

count the number of bonds from c to c not just and random c but the c that has OH attached

primary (1 alcohol)

1 bond c-c

secondary ( 2 alcohol)

2 bonds c to c

tertiary (3 alcohol)

3 bonds from c to c

which alcohol is this

tertiary

what’s the formula for acyclic alkanes

C_nH_2n+2

what’s the formula for pentane

C₅H₁₂

what’s the formula for cyclohexane

C₆H₁₂

define isomers

2 or molecules that have the exact same formula but something about the structure is different

what a constitutional isomer

same formula but different order of bonding

example : different number of LCC (longest continuous chain or parent chain)

one is cycle one is not

different location of C=C

same formula

bending does not change different order of bonding

what is this

constitutional isomer

define stereoisomers

• same formula

• same order of bonding

• different 3D shape

• examples are cis-trans and enantiomers

define cis trans

• molecules that have the same molecular formula and atomic connectivity but differ in the spatial arrangement of their atoms or like two different ways to assemble the same parts. They happen when a molecule has a "stiff" part (like a double bond) that can't rotate.

• Cis: Think "Same side." The matching parts are both on the top or both on the bottom. (A trick to remember: Cis starts with C, like the word "Connected" on one side).

• Trans: Think "Across." The matching parts are diagonal from each other, like a bridge crossing a river.

which is cis which is trans stereoisomer

left is cis , right is trans

when comparing two compounds

if its not the same formula they are different compounds not isomers, isomers have the same formula

if they have the same formula: same exact bonding or structure they are identical

something about the structure is different its an isomer

chiral molecule

that is not superimposable ( not identical) on its mirror image

achiral molecule

one that is superimposable on its mirror image (they are identical)

nonsuperimposable

(not identical) like are hands when mirrored its different from our mirror image

superimpsoable

two socks from a pair are mirror images and identical

How to determine if a molecule is chiral or achiral

If it has a chiral carbon (carbon with 4 different groups bonded to it)

Why are enantiomers important in our body ?

Although they are mirror images of eachother, they are not the same! In particular, a chiral compound can “tell the difference” between the two mirror images of another chiral compound. Since most biomolecules in our body are chiral, our
bodies can “tell the difference” between the two mirror images of an enantiomer pair.

How to name alkene

1. Find the longest chain both carbon atoms of the double bond change suffix to ene

2. Number the carbon chain from the end that gives C=C the lower number

3. Number and name the groups

Name this

2,3-dimethylhexane

How to name alkanes

1. Find the longest chain both carbon atoms of the double bond change suffix to ane

2. Number the carbon chain from the end that gives the first side methyl group lower number

3. Number and name the groups

Meth

1 C

Eth-

2 C

Prop-

3 C

But-

4 C

Name this

2,2- dimethyl-1-pentanol

Name this

4-methylhexanal

Name this

3- methyl 2- butanone

Name this

3,3- dimethyl pentanoic acid

Name these

Left dimethylaniline

Middle trimethylamine

Right dipropylamine

What’s the structure for acetone

Structure for acetic acid

Benzene

Benzoic acid

Ammonia

Aniline

Rules for dehydrating alcohol

There must be a C (with H attached ) adjacent (next door) to alcohol group