BITCH Lec 1

First law of thermodynamics

Energy is conserved (it cannot be created or destroyed)

Second law of thermodynamics

Entropy is ALWAYS increasing

Third law of thermodynamics

The entropy of a system approaches zero as the temperature approaches zero

Enthalpy(H)

total heat energy in a system

Entropy(S)

Disorder!

When does entropy increase?

-Going from ice to liquid

-Going from liquid to gas

-From less to more particles

Positive entropy/ more disorder is more favorable, T/F?

T

Endothermic

ΔH>0, enthalpically unfavorable!

Exothermic

ΔH<0, enthalpically favorable

What requires more energy, breaking or forming a bond?

breaking a bond

Biomolecules assume shape and structure in response to . T/F

True

What bonding do multiple water molecules form when interacting?

Hydrogen bonds

Hydrogen bonds

Water has a partial charge due to its dipole. You can observe that it bonds based on the charge of the mlcl its bonding to

How does water interact with non-polar solutes?

Water forms a ring around the non-polar

solute, using hydrogen bonding, without

interacting with the solute.

Aggregation

Water forms a ring around the non-polar

solute, using hydrogen bonding, without

interacting with the solute.

The water ring formed around a hydrophobic or nonpolar solute is called?

Sphere of hydration

pH=

-log[H⁺]

pOH=

-log[OH]

pH+pOH=

14

At pH=7 what is true of the H⁺ and the OH^-?

they are equal! (OH^-=H⁺)

Bronsted-Lowry acid and base theory

Acid is the proton donor

Base is the proton acceptor

What does pKa describe?

the strength of an acid

Henderson-Hasselbach Equation

pH=pKa​+log([A−]​/[HA])

Titration curve

plot of pH vs. the amount of strong base acid

Inflection point

The point on a titration curve where enough base has been added to neutralize 50% of the acid

Equivalence point

point where enough base has been added to exactly neutralize the acid

a-carboxyl-group pK_a

2

a-Amino group pK_a

9

pH<pK_a

acidic/protonated state is preferred

pH>pK_a

basic/de-protonated state is preferred

All amino acids are weakly polyprotic acids that undergo multiple ionization events T/F?

True

Zwitterion

A molecule containing both positive and negative functional groups with an overall net electrical charge of zero