3/7/15 Exam 2 Review
Supplemental Instruction
Iowa State University / Leader: / Tina Akinyi
Course: / Chem 177
Instructor: / David Appy
Date: / 3/7/15
  1. What is the molarity of sodium ions in a solution prepared by diluting 250.0 mL of 0.55 M Na2SO4 to 1.25 L
  1. 0.110 M
  2. 0.138 M
  3. 0.220 M
  4. 0.275 M
  1. The solubility of K2Cr2O7 in water is 125 g/L at 200C. How many moles of K2Cr2O7 are contained in 50.0 mL of this solution at 200C?
  1. 0.0202 moles
  2. 0.0212 moles
  3. 0.0200 moles
  4. 0.02 moles
  1. A mixture is prepared by adding 50.0 mL of 0.200 M NaOH to 75.0 mL of 0.100 M NaOH. What is the [OH-] in the net mixture?
  1. 0.0600 M
  2. 0.0800 M
  3. 0.140 M
  4. 0.233 M
  1. What is the oxidation state/number of Mn in each of the following solutions?
  1. MnO4-
  2. Mn2O3
  3. Mn
  4. MnSO4
  5. MnO22-

For the following reactions (5-7) indicate the reducing and oxidizing agents. Write the ionic and net ionic equations for reactions 6 and 7.

  1. PbO2(s)+ NaCl (aq) → NaClO (aq)+ Na[Pb(OH)3] (aq)
  2. 6Sb (s) + 10HNO3(aq) →3Sb2O5(s) + 10NO(g) + 5H2O (l)
  3. 3Cu(s) + 8HNO3(aq) → 3Cu(NO3)2(aq) + 2NOg) + 4H2O(l)

For the following acid/base neutralizations, complete the reactions and write the net ionic reactions.

  1. Cu(OH)2(s) + HC2H3O2(aq) →
  2. MgCO3(s) + HCl(aq) →
  1. What volume (in mL) of 0.0500 M phosphoric acid is needed to titrate completely 25.0 mL of 0.150 M barium hydroxide solution to a phenolphthalein end point?

3Ba(OH)2 (aq)+ 2H3PO4 (aq) → Ba3(PO4)2 (aq) + 6H2O(l)

  1. 50.0
  2. 75.0
  3. 100
  4. 150
  1. How many moles of O2 are required for the complete combustion of 2.2 g of C3H8

to form CO2 and H2O?

  1. 0.050
  2. 0.15
  3. 0.25
  4. 0.50
  1. How many moles of water will be produced from the complete combustion of 4.4g of C3H8?
  1. 0.10
  2. 0.25
  3. 0.40
  4. 0.80
  1. For which reaction is ∆Hrxn0 equal to ∆Hf0 for CuSO4(s)?
  1. Cu2+ (aq) + SO4 2- (aq) → CuSO4(s)
  2. CuO(s) + SO3(g) → CuSO4(s)
  3. CuS(s) + 2O2(g) → CuSO4(s)
  4. Cu(s) + S(s) + 2O2(g) → CuSO4(s)
  1. What is the value of ∆H ̊ (in kJ) for this reaction?

2CuO(s) → Cu2O(s) + ½O2(g)

Where Hf 0 CuO = -156.1

And Hf 0 Cu2O = -170.1

  1. C2H5OH(l) + 3 O2(g) ®2 CO2(g) + 3 H2O(g)

During an experiment 10.00 g of ethanol is completely burned in air to release CO2(g) and H2O(g) as shown in the equation above. During the combustion, 296.6 kJ of heat energy is released. What is the molar enthalpy of combustion, DH ̊comb?

  1. –2966 kJ•mol–1
  2. –1366 kJ•mol–1
  3. –64.36 kJ•mol–1
  4. –29.66 kJ•mol–1
  1. For which of the reactions below is (are) the heat of reaction equal to the heat of formation?
  1. ½ N2(g) + O2(g) ®NO2 (g) ∆H rxn > 0
  2. SO2(g) + ½ O2(g)®SO3(g) ∆H rxn< 0
  1. I. Only
  2. II. Only
  3. Both I. and II.
  4. Neither I nor II
  1. Given chemical equations for these reactions

·  S(s) + O2(g) ®SO2 (g) ∆H = –296.8 kJ•mol–1

·  H2(g) + ½ O2(g) ®H2O(l) ∆H = –285.8 kJ•mol–1

·  H2(g) + S(s) ®H2S(g) ∆H= –20.6 kJ•mol–1

What is the value of ∆H rxn for the reaction below?

2H2S(g) + 3O2(g) ®2H2O(l) + 2SO2(g)

A.  –603.2 kJ•mol–1

B.  –562.0 kJ•mol–1

C.  –1206.4 kJ•mol–1

D.  –1124.0 kJ•mol–1

18.  Find the ΔH rxn for the reaction below, given the subsequent reactions and their ΔH rxn values: 1/2H2(g) +1/2Cl2(g)→HCl(g)

·  COCl2(g) + H2O(l) → CH2Cl2(l) + O2(g) ΔH = 47.5 kJ

·  2HCl(g) + 1/2O2(g) → H2O(l) + Cl2(g) ΔH = 105 kJ

·  CH2Cl2(l) + H2(g) + 3/2O 2(g) → COCl2(g) + 2H 2O(l) ΔH = -402.5 kJ

  1. -230 kJ
  2. -460 kJ
  3. -115 kJ
  4. -116.3 kJ
  1. Calculate the frequency of light that corresponds to the following wavelengths in a vacuum.
  1. 12 km
  2. 45 pm
  3. 700 nm
  1. . Calculate the energy of photons of the following types
  1. 423 GHz
  2. 12 cm
  3. 350 nm
  1. What is wavelength of a neutron (m = 1.67 E-27 kg) traveling at a speed of C/500 through a vacuum?

(C= 3.00 E 8 m·s-1)

  1. For which of the following transitions would a Hydrogen atom absorb a photon with the longest wavelength?
  1. n=1 to n=2
  2. n=3 to n=2
  3. n=5 to n=6
  4. n=7 to n=6
  1. How much energy and frequency would be released if a Hydrogen electron transitioned from the n=4 to the n=3 energy level?
  1. 2.043 E-18 J
  2. 3.981 E-18 J
  3. 1.958 E- 18 J
  4. 1.050 E-19 J
  1. Which quantum numbers represent the orbitals being filled in the ground state for the elements Sc (21) to Zn (30)?
  1. n= 3, 1= 1
  2. n= 3, l= 2
  3. n= 4, l= l
  4. n= 4, l= 2
  1. Which must represent an atom in an excited state?
  1. 1s22s22p1
  2. 1s22s22p2
  3. 1s22s22p23s1
  4. 1s22s22p5
  1. What is the ground state electron configuration of a 27Co atom in the gas phase?
  1. 1s22s22p63s23p63d7
  2. 1s22s22p63s23p63d9
  3. 1s22s22p63s23p63d84s1
  4. 1s22s22p63s23p63d74s2
  1. How many orbitals have the quantum numbers: n = 4, l= 3, ml= 0
  1. 7
  2. 3
  3. 1
  4. 0
  1. Which set of quantum numbers (n, l, ml, ms) is not permitted by the rules of quantum mechanics?
  1. 1, 0, 0, ½
  2. 2, 1, –1, - ½
  3. 3, 3, 1, – ½
  4. 4, 3, 2, ½
  1. What is the maximum number of electrons that occupy the n = 3 level?
  1. 6
  2. 8
  3. 10
  4. 18
  1. Write the noble gas electron configuration for each of these atoms and indicate how many valence, unpaired and core electrons there are in each.
  1. Fe
  2. Ge
  3. Ir
  4. Ti
  5. S2-
  6. Ag
  7. Cr 3+
  8. Sn 2+