GChem Flashcards
(69 cards)
Equavalance point
- weak acid+strong base=equlvalence point above 7
PH calculation
- A quick trick to find pH if you’re given [H+] is to take the exponent, and subtract it by 0. (whatever the first number is).
- So if you’re given H+ = 4.9 x 10^-5, the pH is 5 - 0.4 = 4.6
Handerson Hasselbalch Equation
- Calculate the pH of a buffer
Increasing surface area increase BP
IM and BP
the different derivatives for the gas laws (and their names)
So, the ideal gas law is PV=nRT.
Boyle- Sound similar to “boil” which makes me think of temperature so T is constant. “n” is constant. so P1V1=P2V2
Gay-lussac- I just imagine a sack filled with water and that makes me think of volume so V is constant. “n” is constant so P1/T1=P2/T2
Charles- Lol, I have a friend named Charles so I just think of him with a P shaped scar on his forehead kind of like Harry Potter so P is constant. Idk, it sticks lol. “n” is constant so V1/T1=V2/T2.
Avogadro- I think of Avogadro’s number and this is the only time “n’ is not constant. T is constant so (n1/V1)=(n2/V2)
Just another way of thinking about them. I used to get these mixed up so I had to find a way to think about them haha.
Ea-activation energy
Spontaneous rxn and entropy
Reaction rate law
Gibbs free energy
- The amount of energy in a substance that can be used for work or chemical reactions
- Available energy
Vapor pressuren (VP)
- a measure of the tendency of a material to change into the gaseous or vapour state, and it increases with temperature
- BP is when VP=atmospheic pressure
- High VP= highly volatile= easily evaporate–> doesn’t like high Temperature–>lower BP
- Higher atmospheric pressure–>lower BP (high pressure cooker)
- (a higher atmospheric pressure indicates a higher percentage of gas molecules that are not the compound of interest. For instance, in a water and air system, a high pressure indicates that there are more molecules of air (or the molecules are moving faster). This means that in order for the water to want to turn into the vapor phase, more heat will be needed to overcome this high pressure. This leads to an elevated boiling point. The opposite is also true, as decreasing pressure indicates less molecules of air (or slower velocity), thus indicating a lower boiling point)
Solutes
* Adding Non-volatile solutes–>decrease VP
–>increase BP*
* Solutes disrupt overall bonding between solvent liquids. This prevents solutes from escaping as easily but also prevents it from solidifying since the 3d lattice structure of solids is disrupted (ie ice)–>increase BP temperature
Summary of periodic table trends
Gibbs Free energy-the energy within the system to do the work
- ΔG =0 if Keq = Q because at equilibrium there is a dynamic halt of net changes in energy or composition; forward rate=backward rate
-
Q < Keq: ∆G < 0: forward reaction has not reached equilibrium: [Reactants] > [products]
Forward reaction rate increases to restore equilibrium - Q > Keq: ∆G > 0: forward reaction has exceeded equilibrium: [Products] > [reactants], Reverse reaction rate increases to restore equilibrium
Another form of Gibbs free energy
- important to understand each individual variable and to simplify the question stem.
* constants (8.314 J/mol*K)
Why does inductive effect make molecules more acidic?
- when an electronegative atom is attached to a molecule, it pulls electron density away from the acidic hydrogen, making the hydrogen more positive and therefore easier to donate, thus increasing the acidity of the molecule
- Acids are electron acceptors(proton donors)
differences between nucleophilicity and basicity
- Nucleophilicity involves the ability of a species to attack an electrophile, which is determined by how quickly the attack occurs (kinetics).
- Basicity, on the other hand, is about the stability of the protonated species once the proton is transferred (thermodynamics)
Thermodynamics
- Acidity/basicity is a measure of thermodynamics and where the equilibrium and Keq will land
OIL RIG
Oxidation is loss of electrons=more positive=less negative
IR spectroscopy
bicarbonate ion
Electrolytic Cell vs. Galvanic (Voltaic) Cell
- **always true:
- e- from anode to cathode (ox–>cat)**
***Oxidation at anode, reduction at cathode
“An OX, Red Cat” **
→ Anode = Oxidation, Cathode = Reduction (applies to both). - Galvanic: “Good” (spontaneous, energy-producing)
- Electrolytic: “Endothermic” (requires energy input)
standard cell potential
- If free energy negative, then E cell positive
- signs are opposite
Faraday’s constant
