1. During a hot day a section of railroad track is observed to increase temperature from 50° to 110°C. The section of track is made of iron, and has a mass of 233 x 10³ moles. If the specific heat of iron is 0.45 J g^-1 K^-1, how much heat energy was absorbed by the section of track? (5 points)

 

 

 

 

 

 

2. 50 mls of an aqueous solution of NaOH and 100 mls of an aqueous solution of HCl are combined and allowed to react in a constant pressure calorimeter. The reaction generated 2.51 kJ of heat energy. Assuming the specific heat of water is 4.18 J g^-1 K^-1 and the density of water is 1.0g/ml, what will be the temperature change of the solution? (5 points)

 

 

 

 

 

3. Given the following information:

C(s) + 2H₂(g) + 1/2O₂(g) -> CH₃OH(l) DH = -239 kJ

C(s) + O₂(g) -> CO₂(g) DH = -394 kJ

H₂(g) + 1/2O₂(g) -> H₂O(l) DH = -286 kJ

Calculate DH for the combustion of 15 grams of methanol (10 points)

 

 

 

 

 

 

 

 

 

4. From the information and results in question #3 draw an enthalpy diagram which shows the formation of CH₃OH(l), CO₂(g) and H₂O(l) from elemental forms, and which also shows the enthalpy associated with the combustion of CH₃OH(l) to form CO₂(g) and H₂O(l) (10 points)

 

 

 

 

 

 

 

 

 

 

 

 

 

5. An electron transitions from the n=4 to the n=1 principle quantum number in the hydrogen atom. Is energy emitted or absorbed for the associated electron transition? What is the wavelength of the associated photon? Is this photon visible, and if not, what part of the electromagnetic spectrum is the wavelength located? (5 points)

 

 

 

 

 

 

 

6. List the various subshells, and the number of orbitals in each subshell, for the shell with a principle quantum number of 3. How many total orbitals are there? (5 points)

 

 

 

 

 

 

 

 

 

7. What is the effective nuclear charge on the 4s valence electrons of Calcium? (5 points)

 

 

 

 

8. What elements are represented by the following electron configurations? (10 points)

1s² 2s² 2p⁴

[Ne] 3s²

1s² 2s² 2p⁶ 3s² 3p⁶

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁴

[Ar] 4s¹ 3d¹⁰

9. Write orbital diagrams for the following elements (10 points)

Fe

 

 

C

 

 

10. How does the effective nuclear charge change as you move from right to left across the periodic table? How does the effective nuclear charge change as you move up a group in the periodic table? (5 points)

 

 

 

 

11. Of the Noble gas elements Ne, Ar and Kr, which one would have its n=2 orbital shell closest to the nucleus? (5 points)

 

 

 

 

12. Which element, or ion, below has the lowest ionization energy? (5 points)

Na⁺ Cl^- O^2- Mg²⁺ Li

13. Given the following information, determine the bond length for diatomic Oxygen (5 points)

C-O 1.43Å

C-C 1.54Å

C-N 1.43Å

N-N 1.47Å

14. For the following pairs of elements indicate which one most likely has a more negative (i.e. greater) electron affinity (5 points)

Li Be

S Cl

F Ne

Mg Al

Ar K

15. Name five characteristics of metals (5 points)

a)

b)

c)

d)

e)

16. Write the expected balanced equations for the following reactions involving metals (be sure to include the states of the reactants and products): (5 points)

a) Magnesium oxide plus water

b) Calcium oxide plus a dilute solution of hydrochloric acid