MOCK EXAM (FOR PRACTICE ONLY)

COURSE: CHEM 1001 A

NAME: Taliah Hyjazie

It is most beneficial to you to write this mock midterm UNDER EXAM CONDITIONS. This means:

1. • Complete the midterm in 1 hour and a half.

1. • Work on your own and attempt every question.

1. • Keep your notes and textbook closed.

After the time limit, go back over your work with a different colour or on a separate piece of paper and try to do the questions you are unsure of. Record your ideas in the margins to remind yourself of what you were thinking when you take it up at PASS.

The purpose of this mock exam is to give you practice answering questions in a timed setting and to help you to gauge which aspects of the course content you know well and which are in need of further development and review. Use this mock exam as a learning tool in preparing for the actual exam.

Please note:

· Complete the mock exam before attending the take-up session. During the session you can work with other students to review your work.

· Often, there is not enough time to review the entire exam in the PASS workshop. Decide which questions you most want to review – the Facilitator may ask students to vote on which questions they want to discuss in detail.

· Facilitators will not distribute an answer key for mock exams. The Facilitator’s role is to help students work together to compare and assess the answers they have. If you are not able to attend the PASS workshop, you can work alone or with others in the class.

· PASS worksheets are designed as a study aid only for use in PASS workshops. Worksheets may contain errors, intentional or otherwise. It is up to the student to verify the information contained within by attending the PASS workshop.

Good Luck writing the Mock Exam!!

Take-up Session: December 11th 4:05 – 7:05 pm

Office Hour: December 12th 5:05 – 7:05 pm

Zoom Meeting Information: Sent by email and posted to CuLearn

Contact Information: taliahhyjazie@cmail.carleton.ca

Multiple choice questions:

1. When the system is at equilibrium.

a. The sum of the concentration of A and B must be equal the sum of the concentrations of C and D

b. The forward reaction has stopped

c. Both the forward and reverse reaction has stopped

d. Neither the forward nor the reverse reaction has stopped

2. Consider the following reversible reaction. In a 3.00 L container, the following amounts are found in equilibrium at 400: 0.0420 mol N2, 0.516 mol H2 and 0.0357mol NH3. Evaluate Kc.

a. 0.202

b. 1.99

c. 16.0

d. 4.94

e. 0.503

3. At 445, Kc for the following reaction is 0.020.

[HI] = 2.0 M, [H2] =0.50 M, and [I2] = 0.10 M. Which one of the following statements concerning the reaction quotient, Qc, is true?

a. Qc = Kc; the system is at equilibrium

b. Qc is less than Kc; more H2 and I2 will be produced

c. Qc is less than Kc; more HI will be produced

d. Qc is greater than Kc; more H2 and I2 will be produced

e. Qc is greater than Kc; more HI will be produced

4. A quantity of HI was sealed in a tube, heated to 425 and held at this temperature until equilibrium was reached. The concentration of HI in the tube at equilibrium was found to be 0.0706 M. Calculate the equilibrium concentration of H2 for the gas-phase reaction with a Kc = 54.6.

a. 9.55 x10-3 M

b. 1.17 x10-3 M

c. 1.85 x10-4 M

d. 4.78 x10-3 M

e. 2.34 x10-3 M

5. Consider the gas-phase equilibrium system represented by the equation:

Given that the forward reaction is endothermic, which of the following changes will decrease the equilibrium amount of H2O?

a. Adding more oxygen

b. Adding a solid phase catalyst

c. Decreasing the volume of the container (the total pressure increases)

d. Increasing the temperature of constant pressure

e. Adding He gas

6. At equilibrium, a 1.0 L container was found to contain 0.20 moles of A, 0.20 M of B, 0.40 mol of C, and 0.40 mol of D. If 0.10 moles of A and 0.10 moles of B are added to this system, what will be the new equilibrium concentration of A?

a. 0.37 M

b. 0.47 M

c. 0.87 M

d. 0.23 M

e. 0.15 M

7. What is the equilibrium constant for a reaction that has a value of =-41.8 kJ at 100?

a. 1.01

b. 7.1 x105

c. -5.87

d. 1.4 x10-6

e. 13.5

8. For a specific reaction, which of the following statements can be made about K, the equilibrium constant?

a. It always remains the same at different reaction conditions

b. It increases if the concentration of one of the products is increased

c. It changes with changes in temperature

d. It increases if the concentration of one of the reactants is increased

e. It may be changed by the addition of a catalyst

9. The pressure of a gas is 750.0 torr when its volume is 400.0 mL. Calculate the pressure if the gas is allowed to expand to 600.0 L at constant temperature.

a. 0.660 atm

b. 1.48 atm

c. 500.0 atm

d. 1125 atm

10. A gas exerts a pressure of one atm at standard temperature. What must the temperature be adjusted to for the gas to exert a pressure of 4.00 atm?

a. -205

b. 68.3

c. 819

d. 1092

11. Equal number of moles of CO2(g), N2(g), and NH3(g) are placed in a sealed vessel at room temperature. If the vessel has a pinhole-size leak, which of the following will be true after some of the gas mixture has effused?

a. I only

b. III only

c. I and II

d. II and III

e. I, II, and III

12. Real gases vary from the ideal gases at conditions of

a. High temperature and low pressure

b. Both high temperature and high pressure

c. Both low temperature and low pressure

d. Low temperature and high pressure

e. Both high density and low density

13. The temperature of a sample of an ideal gas confined in a 2.0 L container was raised from 27 to 77. If the initial pressure of the gas was 1,200 mmHg, what was the final pressure of the gas?

a. 600 mmHg

b. 1,400 mmHg

c. 2,400 mmHg

d. 2,100 mmHg

e. 3,600 mmHg

14. A gaseous mixture of oxygen and nitrogen is maintained at a constant temperature. Which of the following MUST be true regarding the two gases?

a. Their average kinetic energies will be the same

b. Their average molecular speeds will be the same

c. Their partial pressures will be the same

d. Their total masses will be the same

e. Their densities will be the same

15. The kinetic molecular theory makes several assumptions about ____ and ____ of molecules.

a. Rotational energy and density

b. Motion and presence of intermolecular forces

c. Density and motion

d. Motion and energy

e. None of the above

16. Which of these would result in more frequent collisions?

a. Bigger molecules

b. Higher pressure

c. Lower temperature

d. All of the above

e. B and C only

17. Which of the following statements related to the kinetic molecular theory is FALSE:

a. One of the assumptions of the kinetic molecular theory is that the size of molecules is negligible

b. The average kinetic energy of particles decreases when the temperature is increased

c. Gas particles are in constant motion and move independently of each other

d. One limitation of the kinetic-molecular theory is that it does not put into account the intermolecular forces of attraction between gas molecules

e. Mean free path is the average distance that a molecule travels between collisions

18. In which of the following pairs of physical changes are both changes exothermic?

a. Sublimation, evaporation

b. Freezing, melting

c. Freezing, condensation

d. Melting, sublimation

19. Identify the conjugate acid-base pairs in each equilibrium.

a. Acid, base, conjugate base, conjugate acid

b. Base, acid, conjugate base, conjugate acid

c. Acid, base, conjugate acid, conjugate base

d. Base, acid, conjugate acid, conjugate base

20. Based on the following reaction, predict whether the equilibrium lies primarily to the left or the right.

a. The equilibrium lies primarily to the right

b. The equilibrium lies primarily to the left

c. No preference

d. Insufficient information to answer question

21. Which complex ion would you expect to be more acidic: or ?

a. because Pb is less electronegative than Sn

b. because Sn is more electronegative than Pb

c. They would be equally acidic because they both have a charge of 2+

d. Insufficient information

22. Arrange the hydrides in order of increasing base strength in aqueous solution: LiH, RbH, CsH, and NaH.

a. LiH < RbH < NaH < CsH

b. CsH < RbH < NaH < LiH

c. RbH < CsH < NaH < CsH

d. LiH < NaH < RbH < CsH

23. Arrange the following in order of increasing strength and determine which would have the highest percent ionization given the same initial concentration of each acid.

I. Acid A: pKa = 1.52

II. Acid B: pKa = 6.93

III. Acid C: pKa = 3.86

a. I < II < III; highest percent ionization is acid C

b. II < III < I; highest percent ionization is acid A

c. I < III < II; highest percent ionization is acid A

d. II < III < I; highest percent ionization is acid B

e. I < III < II; highest percent ionization is acid B

24. Determine Ka and pKa of boric acid [B(OH)3]. The pKb of its conjugate base is 4.80.

a. Ka = 1.58 x 10-10; pKa = - 9.20

b. Ka = 3.16 x 10-17; pKa = 9.20

c. Ka = 2.51 x 10-13; pKa = 9.20

d. Ka = 6.31 x 10-10; pKa = 9.20

e. Ka = - 5.012 x 10-10; pKa = 9.20

25. An aqueous solution of a substance is found to have [H3O]+ = 2.48 x 10-8 M. Is the solution acidic, neutral, or basic?

a. Acidic

b. Basic

c. Neutral

d. Insufficient information

26. Calculate the pH and the pOH of a solution of 25.0 mL of 2.3 x 10-2 M HCl, diluted to 100 mL

a. 2.0; 10.78

b. 2.6; 11.13

c. 1.22; 12.78

d. 1.01; 11.13

e. 3.8; 10.78

27. In the following reaction, which is the Lewis acid, and which is the Lewis base?

a. NH3 is the Lewis acid; NH4+ is the Lewis base

b. NH4+ is the Lewis acid; NH3 is the Lewis base

c. H+ is the Lewis acid; NH3 is the Lewis base

d. NH3 is the Lewis acid; H+ is the Lewis base

28. What is the wavelength of electromagnetic radiation which has a frequency of 4.464 x 1014 s-1?

a. 1.338 x 1023 m

b. 1.489 x 10-6 m

c. 6.716 x 10-7 m

d. 671.6 nm

e. 7.472 x 10-15 nm

29. Which one of the following types of radiation has the lowest frequency?

a. FM radio waves

b. Infrared radiation

c. X-rays

d. Ultraviolet rays

30. What is the energy, in joules, of one photon of microwave radiation with a wavelength of 0.158 m?

a. 1.26 x 10-24 J

b. 3.14 x 10-26 J

c. 3.19 x 1025 J

d. 3.49 x 10-43 J

31. Which statement below is true with regard to Bohr’s model of the atom?

a. The model accounted for the absorption spectra of atoms but not for the emission spectra

b. The model could account for the emission spectra of hydrogen and for the Rydberg equation

c. The model was based on the wave properties of the electron

d. The model accounted for the emission spectra of atoms, but not for the absorption spectra

32. Given the following sets of quantum numbers for n, l, ml, and ms, which one of these sets is NOT a possible set for electron in an atom?

n l ml ms

a. 3 2 2 -1/2

b. 3 1 -1 1/2

c. 4 3 2 -1/2

d. 4 3 -2 -1/2

e. 5 2 3 ½

33. Based on the Aufbau principle and other applicable guiding principles, what ground state electronic configuration would one reasonably expect to find for technetium (Z=43)

a. [Kr] 4s2 3d5

b. [Kr] 4s2 4d5

c. [Kr] 4d7

d. [Kr] 5s2 4d5

e. [Kr] 5s2 5d5

34. Which of the following would have the largest radius?

a. Ca

b. Ba

c. K

d. Mg

e. C

35. Which one of the atoms listed below has the largest value for the first ionization energy?

a. Al

b. Sr

c. Ga

d. Cr

e. Fr

36. Which of the following species has 120-degree bond angles?

a. NCl3

b. PH3

c. ClF3

d. BCl3

37. Which of the following species has a trigonal planar shape?

a. NO3-

b. CO2

c. N3

d. NO2-

38. What type of geometry does four sp3 hybrid orbitals adopt?

a. Linear

b. Trigonal planar

c. Octahedral

d. Tetrahedral

39. Arrange the following in increasing order of solubility in water: Xe (g), KBR (s), SO2 (g), He (g), CH3CH2CH2CH2OH

a. KBR (s) < He (g) < Xe (g) < SO2 (g) < CH3CH2CH2CH2OH

b. KBR (s) < CH3CH2CH2CH2OH < SO2 (g) < Xe (g) < He (g)

c. He (g) < Xe (g) < SO2 (g) < CH3CH2CH2CH2OH < KBR (s)

d. KBR (s) < SO2 (g) < Xe (g) < CH3CH2CH2CH2OH < He (g)

40. What is the hybridization of both carbon atoms in ethyne?

a. sp2

b. sp3

c. sp

d. None of the above

41. The boiling point of CH4 is much lower than that of HF. This is because:

a. Of hydrogen bonding in HF

b. Of ion-dipole interaction in CH4

c. CH4 is polar

d. HF is more polarizable

e. Of dipole-dipole interaction in CH4

42. At room temperature, F2 and Cl2 are gases while Br2 is a liquid and I2 is a solid. This is because:

a. Dipole-induced dipole interactions increase with molecular size

b. Dispersion interactions increase with molecular size and polarity increases with molecular size

c. Dispersion interactions increase with molecular size

d. Dipole-dipole interactions increase with molecular size

e. Polarity increases with molecular size

43. One of the reasons that solid CuSO4 dissolves in water is:

a. The electrostatic force of attraction between Cu2+ and the SO42- ions

b. Instantaneous dipole-induced dipole forces (dispersion or London forces) between the Cu2+ and the SO42- ions

c. The ion-dipole forces between the ions and the water molecules

d. Instantaneous dipole-induced dipole forces (dispersion or London forces) between the water molecules

e. The hydrogen bonding between water molecules

44. Which species contains a sp2-hybridized atom?

a. BeH2

b. BH3

c. NH3

d. H3O+

Short Answer Questions:

1. A hydrogen lamp gives only certain colours of light. What does this tell us about the hydrogen atom?

2. Oxygen gas is obtained in cylinders with internal dimensions 2.00 m in height and 20.0 cm in diameter. The pressure is 100 bar and T = 18.0. Calculate the mass of oxygen gas in the cylinder given that the volume of a cylinder is .

3. Calculate the average (root mean square) speed of oxygen molecules (in m/s) at 15.0.

4. Fill the following table according to the following diagram:

1

4

3

2

Atom

Steric number

Hybridization

Name of shape of atoms around this atom

1

2

3

4

5. Draw the three resonance forms for CO32-

6. Explain why HOI is a weaker acid than HOCl

7. 0.0800 bar of hydrogen gas and 0.0200 bar of carbon dioxide are placed into a container at a temperature of 800, find the partial pressures of each gas when equilibrium is reached if the equilibrium constant of this reaction is 0.920. Put your final answers in bar. The reaction is given below.

8. Calculate the pH of a 3.0 M solution of sodium nitrite, NaNO2(aq) with a and the Kb of NaOH is very large.