Quantum Chemistry
1s
Is a Bronsted-Lowry base a proton donor or proton acceptor?
bases are proton acceptors
Show the Kw expression for the auto-ionization of water
H2O <--> H+ + OH-
Kw = [H+][OH-]
What is the mathematical definition of Molarity?
moles of solute / Volume (L) of solution
How many calories are in a food Calorie?
What is the equivalent unit to a food Calorie?
1000 calories = 1 Calorie
a food Calorie is also known as a kilocalorie (kcal)
How many 3s, 3p, and 3d orbitals exist for an electron in n=3 energy level?
(3s) = 1-s orbital, (3p) 3-p orbitals, (3d)-5-d orbitals
Write a balanced chemical equation for ammonia + water (weak base in water) on the board to show a hydroxide ion as a product. You must show a conservation of charge
NH3 + H2O --> NH4+ + OH-
Show the Ka expression for the partial ionization of HCN in water
HCN <--> H+ + CN-
Ka = [H+][CN-] / [HCN]
What is the mathematical definition of the concentration unit % (m/m)
Show how you'd apply this to find the % concentration of 20 g NaCl dissolved in 80 g of water.
mass of solute/mass of solution x 100%
20 g NaCl/ (20 g NaCl + 80 g Water)
x 100% = 20% NaCl
Explain why you can't use q = MCDT
(heat = m-CAT) to find the heat associated with melting or boiling a substance
q = MCDT is only appropriate to use when finding the heat associated with an observation of temperature change. Melting and Boiling are changes in state which occur at stable temperatures.
What chemical families (groups) are exceptions when writing electron configurations? What is the rule for these elements
d4 and d9 familes. Promote 1 electron from the s-subshell into the d-subshell
draw the chemical structure of acetic acid and circle the proton that is donated
CH3 group connected to C=O. The carbonyl carbon is connect to OH. The H of the OH is the protic hydrogen
Show the Kb expression for the partial ionization of ammonia in water
NH3 + H2O <--> NH4+ + OH-
Kb = [NH4+][OH-] / [NH3]
Whenever you want to find out how many moles of solute are dissolved in an aqueous solution what mathematical approach would you take?
Multiplying the volume of solution x the concentration in molarity units = moles of solute alone
MV = n
Explain what this equation communicates
-q (system) = +q (surroundings)
The heat energy that is released from a warmer substances is equal to the same heat energy that is absorbed by the cooler substance it is in contact with.
dxz - clover on the xz plane, dyz - clover on the yz plane, 2 electrons max - Pauli Exclusion Principle
Name 3 strong acids and their chemical formula
HCl, HBr, HI, H2SO4, HNO3, HClO4, HClO3
What is the definition of pH? Write it and say it in words
pH = -log [H+]
The pH is equal to the negative log of the hydrogen ion (proton or hydronium ion) concentration.
Describe what a standardization titration is involving KHP. (What's the point of it)
a standardization titration is a titration to find the concentration of a solution using a known standard to titrate against such as measuring the mass of KHP directly which is accurate and precise.
Explain the different circumstances you would use the following two similar equations
q(system) = -q(surroundings)
q(reaction) = -q(calorimeter)
q(system) = -q(surroundings) - used to find one of the following variables mass, specific heat, or temperature change of two substances in contact with each other
q(reaction) = -q(calorimeter) - Used to find the heat of a reaction through the temperature change of the water in a calorimeter
How many electrons max can occupy the n=4 energy level?
4s = 2, 4p = 6, 4d = 10, 4f = 14 = 32 total electrons
In The equation
CO3^2- + H2O <--> HCO3- + OH-
Explain how bicarbonate ion is either the conjugate base or the conjugate acid of carbonate ion.CO3^2 acts as a weak base as it accepts a H+ from water, making HCO3- it's conjugate acid.
To find the concentration of base (OH's) from a pH meter, what do you have to do if using 10^-x =[X] method?
you'd have to subtract pH from 14 = pOH and then
10^-pOH = [OH-]
Name two methods of finding the concentration of an unknown HCl solution that you had a lab experience with in Chem 1A
1. Titration with base
2. pH meter 10^-pH = [H+]
and [H+] = [HCl]
Set up the equation that would solve for the specific heat of a metal in a coffee cup calorimetry experiment
-q (hot metal) = +q (cool water)
-(m x Cs x DT) of metal = (m x Cs x DT) of water
Solve for Cs of metal