1) What is the sum of the coefficients when the following is balanced with the smallest integer coefficients?
PCl3(l) + Cl2(g) + P4O10(s) → POCl3(l)
A) 3
B) 18
C) 45
D) 10
E) 23
2) In the following reaction:
2 KClO3(s) → 2 KCl(s) + 3 O2(g)
14.0 g KClO3 yielded 1.40 g KCl. What is the percent yield?
3) The Haber Process for the production of ammonia is represented by:
3 H2(g) + N2(g) → 2 NH3(g)
If a mixture of 30 g of hydrogen with 10 g of nitrogen produced 8.4 g of ammonia, what was the percent yield?
4) The reaction of aluminum with hydrochloric acid produces hydrogen gas. The balanced chemical equation for the reaction is given below:
2Al (s) + 6HCl (aq) → 2AlCl3 (aq) + 3H2 (g)
If 35.5 mL of H2(g) is collected over water at 26 ◦C and a barometric pressure of 755 mmHg, how many moles of HCl must have been consumed? (The vapor pressure of water at 26 ◦C is 25.2 mmHg.) Show your calculations; include units in every step. (5 marks)
R= 0.08206 atm.L. mol-1. K-1 , T (K) = t (◦C) + 273.15
5) If 4.0 ×1024 molecules of N2, 4.0 g of H2, 6.0 moles of O2 are placed in an 8.2 L container at 127°C, what would be (i) the mole fraction of each gas, (ii) the total pressure in the flask, and (iii) the partial pressure of each gas? (6 marks)
5) Determine the relative rates of diffusion of hydrogen gas and oxygen gas at 25◦C? (3 marks)
7) . What is the molarity of potassium sulphate, K2SO4, in the solution made when we dilute 14.5 mL of aqueous 2.00 M K2SO4 solution with water to a final volume of 300.0 mL?
8) Which of the following would be considered a solution? (2 marks)
A) Water B) Mercury C) Air D) None of these
9) Sketch all of the orbitals with a principal quantum number equal to 2. (3 marks)
10) The existence of discrete (quantized) energy levels in an atom may be inferred from:
A) diffraction of electrons by crystals
B) X-ray diffraction by crystals
C) atomic line spectra
D) experiments on the photoelectric effect
11) When an electron in an atom goes from a high energy state to a low one, what occurs?
A) Another electron goes from a low energy state to a high one.
B) The atom moves faster.
C) Light is given off.
D) This process is not possible.
E) Light is absorbed
12) Calculate the wavelength in meters of light absorbed by an electron in an atom of hydrogen as it moves from n = 3 to n = 6.
A) 1.09 × 10-6 m
B) 8.22 × 10-7 m
C) 3.28 × 10-6 m
D) 1.83 × 10-7 m
E) 1.65 × 10-11 m
13) An orbital:
I) describes a region of high electron density.
II) describes a region in an atom where an electron is likely to be found.
III) is a wave function resulting from specific values assigned to quantum numbers in wave equations.
IV) describes a spherical region around a nucleus where an electron can be found.
A) II only
B) I and II
C) II and III
D) I, II, and III
E) I, II, III, and IV
14) Which of the following statements concerning quantum numbers is NOT correct?
A) "n" relates the most probable distance from the nucleus.
B) "l" denotes geometric shape.
C) "m" denotes orientation of an orbital with respect to the others.
D) The fourth quantum number refers to electron spin.
E) The four quantum numbers are derived from wave mechanics.
15) In a hydrogen atom, orbitals with the same energy:
I) extend the same distance from the nucleus.
II) have the same principle quantum number, n.
III) are referred to as iso-electronic.
IV) are referred to as degenerate.
V) are represented by 1s and 2s orbitals.
A) I, III, IV
B) I, II, IV
C) I, IV, V
D) I, II, III
E) I, II, III, and IV
16) The ground state electron configuration of Sc is ______.
A) 1s22s22p62d103s1
B) 1s21p62s22p63d5
C) 1s22s22p63s23p63d3
D) 1s22s22p63s23p64s23d1
E) 1s22s22p63s23p64s24p1
17) Show the orbital diagram for the ground state electron configuration of the following:
Cu , Mn, and Fe3+? (6 marks)
18) The electron in a hydrogen atom drops from a higher energy level to the third principle shell, emitting a photon with a of wavelength of 1282 nm in the process. What was the value of n for the higher energy level?
19) The correct electron configuration for Br- is ______.
A) [Br] 3d104s24p6
B) [Ar] 3d104s24p6
C) [Br] 4s23d104p5
D) [Ar] 3d104s24p5
E) [Ne] 3d104s24p6
20) The following are electron configurations for a nitrogen atom, indicate whether the configurations represent the ground state or a state that is inconsistant with Hund's Rule. Justify your answers.
1s 2s 2px 2py 2pz
a) ↑↓ ↑↓ ↑↓ ↑
b) ↑↓ ↑↓ ↑ ↑ ↑
c) ↑↓ ↑↓ ↑ ↑ ↓
d) ↑↓ ↑↓ ↓ ↓ ↓
21) What are the electronic configurations for the following?
a) A phosphorus atom
b) for the stable ion produced by aluminum
22) Give the electronic configurations for: P3-, Pt, Ni, Na, Br