Chemistry Study Guide Oct 2 nd 1 hour Exam Chapter 9- Thermodynamics KE = 1/2 mv 2 w = F? xw = force x distance? A state function refers to a property of the system that depends only on its present state. ? Internal Energy = heat + work? E = q + w? Pressure = Force/Area = P = F/A? Work = – external pressure x change in volume = – P? VEnthalpyH = E + Pvp = ? E + P? V? H = qp? H = H products – H reactants Ideal Gas Law PV = nRT Energy “heat” = 3/2 R? Cv = 3/2 R = “heat” required to change the temp of 1 mol of gas by 1 K at constant volume Energy required = “heat” – energy needed – energy needed to do to change the translational the PV workenergyCp = 3/2 + R = 5/2 R = Cv + R = CpE = 3/2 RT (per mole) ? E = Cv? T (per mole) ? E = n Cv? T”Heat” required = qp = n Cp? T = n (Cv + R) ? T = n Cv? T + nR? T (? E) (PV) ? H = ? E + ? (PV) ? H = ? E + ? (nRT) = ? E + nR? T? H = n Cp? Energy released = energy absorbed = m x Cp x ? T (mass) (specific heat) (change in Temperature) ? E = q + w = q = qv Bomb calorimeter = ? H = ? TCp? Ho reaction = ? ? Hof (products) – ? ? Hof (reactants) Chapter 12 c = ? ? speed of light (3. 0 E 8 m) = (wavelength) (frequency) ? E = nh v or ? E = hv if n = 1 Planck’s constant = h = 6. 626 x 10-34 J sE photon = hv = hc/? KE electron = 1/2 mv 2 = hv – h voE = mc 2 De Broglie? = h / mv PE = -Z e 2/rZ = atomic number = distance between nucleus? ? = ? ? ? 2 = Probability Density = energy level = shape ml = orientation ms = spin Effective nuclear charge = Ziff = Z actual – effect of electron-electron repulsion 1 eV = 1. 602 x 10-19 Ionization Energy (g) ? X+ (g) + e-? First Ionization energy increases as we go across a period from left to right due to shielding effects? Shielding occurs because electrons repel each other? First ionization energy decreases as we go down a group.
? As n increases, the size of the orbital increases, and the electron is easier to remove. ? Exceptions: Be to B – decrease in IE shows that the electrons in 2 s orbital effectively shield the 2 p electron. N to O- drop in IE because of addition of electron in first p orbital that results in a pair that repel each other and make either of them easier to remove. Electron Affinity X (g) + e-? X- (g) ? Down a group – more positive since electron is added at increasing distances from the nucleus.
? Increase across period because effective nuclear charge is increasing. Electro negativity = (Electron Affinity + Ionization Potential) /2 Lattice Energy Li+ (g) + Cl- (g) ? Li Cl (s) Lattice Energy = k (Q 1 Q 2) /r? H = ? D (Bonds broken) – ? D (Bonds formed) Formal charge = (# of valence electrons on a free atom) – (# of valence electrons assigned to the atom in molecule) (Valence electron) assigned = (# of lone pair electrons) + 1/2 (# of shared electrons) 1. Lone pair electrons belong entirely to the atom in question 2. 2. Shared electrons are divided equally between the 2 sharing atoms Chapter 14 Bond Order = (# of bonding electrons – # of anti bonding electrons) /2 Chap 20 CO 2 > CN- > NO 2- > en > NH 3 > H 2 O > OH- > F- > Cl- > Br- > I- (strong field) (weak field) (diamagnetic) (paramagnetic) (Low spin) (High spin) Magnitude of ? for ligand increases as charge on metal ion increases.