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Exam 2 review:

Exam 2 review:. Ag + (aq) + Cl - (aq) -------> AgCl(s) H = -65.5 kJ Calculate H for the formation of 2.5 g of AgCl MW. 143.319 g/mol (AgCl). 2.5 g/143.319 g/mol = 0.0174 mole 0.0174 mol(-65.5 kJ/mol AgCl) = -1.14 kJ Calorimetry problem: example problem:

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Exam 2 review:

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  1. Exam 2 review: • Ag+(aq) + Cl-(aq) -------> AgCl(s) H = -65.5 kJ Calculate H for the formation of 2.5 g of AgCl MW. 143.319 g/mol (AgCl). 2.5 g/143.319 g/mol = 0.0174 mole 0.0174 mol(-65.5 kJ/mol AgCl) = -1.14 kJ • Calorimetry problem: • example problem: 10 g of NaOH is dissolved in 100 mL of water in a calorimeter, the temperature changes from 23.6 to 47.4 °C. Calculate H for the process, assume the specific heat of the solution is 4.184 j/°Kg, the same as water.

  2. Chapter 5 q = specific heat(g solution)(T) q = 4.184j/Kmol(110 g)(26.4 -43.3) = -10953 J moles NaOH = 10g/40 g = .25 mole H = -10953 J/.25 mol = -43812 = 40000 J/mol NaOH. • Hess’s law: • Given a series of reactions, rearrange to find H for the reaction in question: • Example problem: • Given the data: • N2(g) + O2(g) ----> 2NO(g) H =180.7 kJ • 2NO(g) + O2(g) -----> 2NO2 H= -113.1 kJ • 2N2O(g) -----> 2N2(g) + O2(g) H= -163.2 kJ • Calculate: N2O(g) +NO2(g) -----> O2(g) • Enthalpies of formation (the tables of enthalpies of formation): • Hprdts - Hreactants = Hreaction

  3. Chapter 5 • Hess’s law: • Given a series of reactions, rearrange to find H for the reaction in question: • Example problem: • Given the data: • N2(g) + O2(g) ----> 2NO(g) H =180.7 kJ • 2NO(g) + O2(g) -----> 2NO2 H= -113.1 kJ • 2N2O(g) -----> 2N2(g) + O2(g) H= -163.2 kJ • Calculate: N2O(g) +NO2(g) -----> 3NO(g) • NO2 ---- NO(g) + 1/2O2(g)113.1/2 • N2O(g) -----> N2(g) + 1/2O2(g) H= -163.2/2 kJ • N2(g) + O2(g) ----> 2NO(g) H =180.7 kJ • N2O(g) +NO2(g) -----> 3NO(g) H =155.6 kJ

  4. Chapter 5 • Enthalpies of formation (the tables of enthalpies of formation): • Hprdts - Hreactants = Hreaction

  5. Chapter 6 • Chapter 6 • Characteristics of waves (v = ): • What is wavelength? • What is frequency? • Electromagnetic radiation: • E = h • visible spectrum (ROYGBV) • rest of spectrum

  6. Chapter 6 • Chapter 6 • Characteristics of waves (v = ): • Black body radiation • Photo-electric effect • Heisenberg uncertainty: (mvx ≥ h) • Line spectra of atoms • matter waves (De Brogli)

  7. Chapter 6 • Chapter 6 • Wavefunctions and quantum mechanics • wavefunction vs. probability distribution • orbitals and quantum numbers • Quantum numbers • what are the four? • principle (energy) n = 1,2,3... • azimuthal (shape) l = 0,1, 2... n-1 • magnetic (orientation) ml = -l,...0,...+l • spin (differentiates two electrons in same orbital) (±1/2) • naming the l qm: • l=0, s, l=1, p, l=2, d, l=3, f • Shapes of orbitals

  8. Chapter 6 • Chapter 6 • Many electron atoms • Energy of orbitals in H versus other atoms with other electrons.

  9. Chapter 6 • Chapter 6 • Pauli exclusion principle • Hund’s rule (don’t pair until you have to) • Electron configurations

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