Supplemental Instruction
Iowa State University / Leader: / Sara
Course: / Chem177
Instructor: / Kingston
Date: / Sunday, October 26
1) 4 C6H6OH (g) + 25 O2 (g) à 24 CO2 (g) + 14 H2O (g) ∆H= -455 kJ
a. Is the reaction exothermic or endothermic?
b. What is the change in enthalpy given off when 63.4 g C6H6OH is burned (mm = 95 g/mol )
2) If 100.0 mL or 0.500 M HBr and 50.00 mL of 1.00 M NH4OH are mixed in a calorimeter, the temperature goes from 19.0ºC to 301K. You can assume the specific heat and density of the solution to be the same as water. What is the enthalpy change of the reaction: HBr (aq) + NH4OH (aq) à H2O (l) + NH4Br (aq)?
3) 5.00 grams of a new snack is burned in a bomb calorimeter (Ccal = 43.6 kJ/K). The temperature increases from 32.1 C to 39.6 C. There are 25.00 grams of the snack per serving. How many Calories are in one serving of the new snack?
4) Using the given information:
C (s) + O2 (g) à CO2(g) ΔH = -394 kJ
C3H8 (g) + 5O2 (g) à 4H2O (l) + 3CO2 (g) ΔH = -2220 kJ
H2(g) + 1/2 O2(g) à H2O (l) ΔH = -286 kJ
Find ΔH for the reaction:
3C (s) + 4H2(g) à C3H8(g) ΔH =
5) Calculate the ∆Hrxn for the following equation using the enthalpies of formation?
3 PbBr2 (s) + 4 H2O (l) à Pb3O4 (s) + 6 HBr (g) + H2 (g)
∆Hfº (H2(g)) + 6 ∆Hfº (HBr(g)) + ∆Hfº (Pb3O4) – ∆Hfº (H2O (l)) – 3 ∆Hfº (PbBr2)
Molecule / ∆Hfº (kJ/mol)HBr (g) / -36.2
H2O (g) / 241.8
H2O (l) / -285.8
PbBr2 (s) / -277.0
Pb3O4 (s) / -734.7
6) Which subshell contains 3 orbitals?
a. 4s
b. 6f
c. 3p
d. 3d
e. 4d
7) If your microwave radiates waves with a wavelength of 0.34 dm, what is the energy of those waves?
8) Which transition of an electron requires the most energy to take place?
a. n=3 à n=4
b. n=6 à n=2
c. n=1 à n=5
d. n=4 à n=1
9) What is the change in energy when an electron is added to the third energy level of an H+ ion?
10) What would the energy of one mole of photons be is the photons were in the visible light spectrum and where yellow?
a. 200000 J
b. 12000 J
c. 3.9*10-16 J
d. 3.4*10-19 J
11) How many unpaired electrons are in an atoms of Co in its ground state?
a. 1
b. 2
c. 3
d. 7
12) For which element is the ground state electron configuration: [Kr]5s14d5?