Part I. Circle your answers for multiple choice questions
1. 550 nm electromagnetic radiation is in what region of the electromagnetic spectrum?
2. Which of the following choices is false regarding the wave amplitude of electromagnetic radiation?
(Circle all that apply. There may be more than one answer)
A) For visible light, a larger wave amplitude correlates with a brighter light
B) A larger wave amplitude correlates with higher energy photons
C) A larger wave amplitude correlates with a larger number of photons
D) A larger wave amplitude correlates with a longer wavelength
E) A larger wave amplitude correlates with increased wave speed
3. Which of the following compounds will not undergo an acid-base (neutralization) reaction with
4. If the ∆H° for the reaction, 2 Mg (s) + 2 Cl2 (g) → 2 MgCl2 (s), is -1283.6 kJ, what is the standard
enthalpy of formation of magnesium chloride?
A) 0 kJ/mol
B) -320.9 kJ/mol
C) -641.8 kJ/mol
D) 1283.6 kJ/mol
E) -1283.6 kJ/mol
5. Assign the proper oxidation state for the sulfur atom in each of the following species.
a) H2S _________
b) Na2SO4 _________
6. In one sentence, clearly explain why only some wavelengths of light are absorbed when a white light source is directed through a sample of He gas.
7. You place 2.80 g of phosphoric acid (H3PO4) into 150.0 mL of a 1.00 M sodium hydroxide solution. If
the total volume remains constant, identify the following:
a) The concentration of sodium ion at the completion of the reaction: _______________ M
b) The concentration of phosphate ion at the completion of the reaction: _____________ M
c) The concentration of hydroxide ion at the completion of the reaction: _____________ M
8. According to De Broglie’s theory, an electron moving at 12.5% the speed of light will display wave behavior at what wavelength?
9. What is the energy of one mole of radio wave photons with a wavelength of 95.6 meters?
10. Balance the following redox reaction (in either acidic or basic solution – your choice).
I– (aq) + ClO– (aq) → I2 (aq) + Cl– (aq)
11. You measure 48.0 mL of a solution of sulfuric acid with an unknown concentration, and carefully titrate this solution using a 1.500 M solution of KOH and a phenolphthalein indicator. You measure that 34.7 mL of the KOH solution is required to reach the equivalence point. What is the concentration of the sulfuric acid solution?
12. Complete combustion of 1.00 mol of acetone (C3H6O) liberates 1790. kJ of heat (the reaction is shown
below). Given that ΔH°f (CO2) = –393.5 kJ/mol and ΔH°f (H2O) = –285.8 kJ/mol, calculate the standard enthalpy of formation of acetone. Make sure to balance the reaction!
C3H6O (l) + O2 (g) → H2O (l) + CO2 (g)
13. Solid sulfur and oxygen gas react to produce sulfur trioxide as shown below. In a particular experiment, 5.0 g of O2 are reacted with 6.0 g of S8.
S8 (s) + O2 (g) → SO3 (g)
a) If we assume complete consumption of the limiting reactant, what is the mass and identity of the reactant that still remains at the end of the reaction?
c) What is the % yield of SO3 in this experiment if 7.9 g of SO3 are isolated?
14. An iron nail is suspended on a thin wire in a sealed jar of moist air. The surface of the nail becomes red over time.
a) Describe what is happening to the mass of the nail over time.
b) List the chemical changes taking place in the jar