Exam 2 Review
Supplemental Instruction
Iowa State University / Leader: / Ugerah
Course: / CHEM 167
Instructor: / Dr. Bonaccorsi
Date: / 7th October, 2017
  1. A chemist set up a synthesis of phosphorus trichloride by mixing 18.8 g of white phosphorus (P4) with 59.4 g of chlorine gas and obtained 72.4 g of liquid phosphorus trichloride.
  2. Calculate the mass (in g) of phosphorus trichloride that can be made from the reactants.
  1. Calculate the percentage yield of the product.
  1. What volume of 0.25M HCl is needed to completely neutralize a 12.34g sample of Ba(OH)2 in 850ml of water? (molar mass of Ba(OH)2 is 171.34g/mol
  1. A mixture of gas contains 4 moles of O2, 5 moles of N2, and 2 moles of CO2. The total pressure is 12.1 atmospheres. What is the partial pressure of each gas?
  1. Which of the following sets of quantum numbers is invalid?
  2. Which of the following is not a postulate of the kinetic molecular theory of gases?
  3. Gas molecules are in constant random motion
  4. Gas molecules are attracted to each other.
  5. Gas molecules are infinitely small.
  6. All gas molecules behave the same.
  7. Gas molecules have elastic collisions.
  8. Which of the following instruments directly measures the partial pressure of a substance?
  9. Capacitance manometer
  10. Ionization gauge
  11. Mass spectrometer
  12. Barometer
  1. Consider the sine waves representing light of electromagnetic radiation. Which one corresponds to photons with the largest energy?
  1. What conditions do you expect in non-ideal gases?
  1. When chlorine is added to acetylene, tetrachloroethane is formed:

. How many liters of chlorine will be needed to make 75.0 g of ? (The pressure is 1.0 atm, and the temperature is 298 K.)

  1. Which of the following characteristics of trace analysis is incorrect?
  2. Trace analysis means measuring substances in a sample at very low levels of concentration.
  3. Trace analysis can be either destructive or non-destructive.
  4. Atomic Absorption Spectroscopy (AAS) is a form or non-destructive trace analysis.
  5. In AAS, the frequencies of light absorbed depend on the chemical identity of the elements represent.
  6. In X-ray fluorescence (XRF), atoms gain energy from X-rays, causing them to fluoresce.
  7. Which atomic orbital has 3 nodal surfaces?
  8. 3s and 3pb. 3s and 4sc. 4s and 4pd. All p atomic orbitals
  1. A neon atom emits light at many wavelengths, two of which are at 616.4 and 638.3 nm. Both of these transitions are to the same final state.
  2. What is the energy difference between the two states for each transition?
  1. If a transition between the two higher energy states could be observed, what would be the frequency of the light?
  1. Which of the following is an excited-state electron configuration?

a. 1s2 2s2 2p1
b. 1s2 2s2 2p6
c. 1s2 2s2 2p4 3s1
d. [Ar] 4s2 3d10 4p1

  1. Which of the following has the smallest ionization energy?

a. Mg

b. Se

c. Ba

d. Po

  1. Find the wavelength of light that would be emitted when a hydrogen atom undergoes the transition from the state n = 4 to the state n = 2. Express your answer in nm. (hint: the wavelength for the transition 41 is 97.534 nm, 21 is 121.556 nm, and 31is 102.583 nm)
  1. TRUE or FALSE: At a given temperature, all gas molecules in a sample have the same velocity.
  2. According to the kinetic molecular theory of gases, which of the following gases will have the greatest average molecular speed?
  1. HF
  2. H2
  3. Ar
  1. The pressure in a natural gas tank is maintained at 2.20 atm. On a day when the temperature is 15°c, the volume of the gas in the tank is 3.25cm3. What is the volume of the same quantity of gas on a day when the temperature is 31°c?
  1. Write the noble gas core electron configuration for the following species:
  2. Mg
  1. Zn2+
  1. A 0.5 mol sample of oxygen is confined at 0oC and 1atm in a cylinder with a movable piston. The piston compresses the gas so that the final volume is half the initial volume and the final pressure is 2.2 atm. What is the final temperature of the gas in degree Celsius?

21.

22.The retina of a “predator” eye can function in nearly dark condition, at 2.00*10-17J. For light of 685 nm wavelength, how many photons does this energy correspond to?

23.What volume of 1.57 M HCl would react completely with 22.5 g Mg?