CHEM 6A Study Guide - Midterm Guide: Principal Quantum Number, Matter Wave, Atomic Nucleus
Chemistry 6A, Dr. Lam Last Name ______________________
Midterm Exam, Fall 2016, Practice PID____________________________
Part 1: MULTIPLE CHOICE SECTION
All answers to the multiple choice questions must be recorded on your scantron.
1. Which of the following correctly expresses 0.00000890 m in scientific notation?
A) 8.90 × 10−8 m
B) 8.90 × 10−6 m
C) 8.90 × 106 m
D) 8.9 × 10−6 m
E) 8.9 × 10−8 m
2. Select the answer that expresses the result of this calculation with the correct number of significant
figures and with correct units.
2.53 m × 0.01896 m × 119 m
22.68 m + 1.759 m
A) 0.2336 m
B) 0.2336 m2
C) 0.234 m3
D) 0.234 m2
E) 0.234 m
3. Accuracy is a measure of
A) How close a measurement is to the “true” value.
B) An object’s kinetic energy.
C) How well repeated measurements agree with each other.
D) The error inherent in every measurement.
E) The quality of the instrument used in the measurement.
4. Which would be considered a binary molecular compound?
A) NaCl
B) CaCl2
C) FeCl3
D) BaCl2
E) BrCl
5. Which of the following are postulates of Dalton’s atomic theory? (Choose all that apply)
A) In a chemical reaction, no atoms are created or destroyed, and the atoms themselves are not
changed.
B) The nucleus of an atom consists of protons and neutrons.
C) Atoms are composed of protons, neutrons, and electrons.
D) In a chemical reaction, the atoms involved are rearranged, separated, or recombined to form new
substances.
E) The atoms of different elements differ in mass and in chemical behavior.
Chemistry 6A, Dr. Lam Last Name ______________________
Midterm Exam, Fall 2016, Practice PID____________________________
6. Household sugar, sucrose, has the molecular formula C12H22O11. What is the percentage of carbon in
sucrose, by mass?
A) 26.7%
B) 33.3%
C) 41.4%
D) 42.1%
E) 52.8%
7. When the following chemical equation is balanced:
a NH3(g) + b O2 (g) → c NO(g) + d H2O(ℓ)
the sum of all the balancing coefficients (a + b + c + d) is:
A) 8
B) 10
C) 19
D) 24
E) 29
8. Which of the following trend shows elements listed in decreasing metallic character?
A) Ga > Mn > Ca > K
B) Mn > Ca > Ga > K
C) K > Ca > Mn > Ga
D) Ca > K > Ga > Mn
9. One molecule of a compound weighs 2.03 × 10−22 g. The compound is:
A) SO
B) SiO4
C) Al2O3
D) PdO
E) None of these
10. The first ionization energy of carbon is 1.81 aJ. Assuming an ionization efficiency of 22.35%, how
many photons of the lowest possible frequency are required to ionize a sample of carbon that contains
5.32 × 1018 atoms?
A) 2.38 × 1019 photons
B) 4.20 × 10−20 photons
C) 2.73 × 1015 photons
D) 9.11 × 106 photons
11. Which of the following shows the correct order of the first three ionization energies for any given
element?
A) I1 = I2 = I3
B) I1 > I2 > I3
C) I1 < I2 < I3
D) I1 > I2 < I3
E) I1 < I2 = I3
12. Which of the following statements about atoms and subatomic particles is correct?
A) Rutherford discovered the atomic nucleus by bombarding gold foil with electrons.
B) The proton and the electron have identical masses.
C) A neutral atom contains equal numbers of protons and electrons.
D) An atomic nucleus always contains equal numbers of protons and neutrons.
E) The neutron has a positive charge.
13. A runner runs 100.0 m in 48.5 s. What is his de Broglie wavelength at this speed if his mass is 84.5
kg?
A) 7.29 × 10−37 m
B) 3.26 × 10−37 m
C) 3.80 × 10−36 m
D) 1.34 × 10−36 m
Chemistry 6A, Dr. Lam Last Name ______________________
Midterm Exam, Fall 2016, Practice PID____________________________
14. Which of the following statements is false?
A) An orbital can accommodate as most two electrons.
B) Ψ2!at a point tells us the probability density of finding electrons at that point.
C) The spin quantum number of an electron must be either + ½ or − ½.
D) An orbital with a larger principle quantum number (n) has electrons closer to the nucleus.
E) A nodal surface represents a surface with no probability of finding electrons.
I II
Answer questions 15 – 17 by referring to the above orbitals.
15. Identify the type of orbitals for I and II.
A) I: p orbital; II: d orbital
B) I: s orbital; II: p orbital
C) I: d orbital; II: p orbital
D) I: s orbital; II: d orbital
E) I: p orbital; II: s orbital
16. There is no probability of finding electrons at the nucleus for electrons in orbital II.
A) True B) False
17. The subshell containing orbital II contains two other orbitals other than the one shown.
A) True B) False
18. Which set of quantum numbers, n, ℓ , mℓ, ms are allowed (that is, possible) for an electron in an atom?
(Choose all that apply)
A) 2, 1, 0, + ½
B) 3, 0, +1, − ½
C) 3, 2, −2, + ½
D) 1, 1, 0, − ½
E) 2, 1, 0, 0
19. Most of the group 1 metal compounds dissolve readily in water. Which of the following compounds
is expected to have good solubility in water? (Choose all that apply)
A) KF (s)
B) SF4 (g)
C) Al(OH)3 (s)
D) Mg(OH)2 (s)
E) NaOH (s)
19
CHEM 6A Full Course Notes
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2. 53 m 0. 01896 m 119 m. Midterm exam, fall 2016, practice: household sugar, sucrose, has the molecular formula c12h22o11. Assuming an ionization efficiency of 22. 35%, how many photons of the lowest possible frequency are required to ionize a sample of carbon that contains. Answer questions 15 17 by referring to the above orbitals: identify the type of orbitals for i and ii. Which of the following compounds is expected to have good solubility in water? (choose all that apply: kf (s, sf4 (g, al(oh)3 (s, mg(oh)2 (s, naoh (s) Mark a as the answer to this question and in the test form box on your scantron (below id number) Lithium has an atomic mass of 6. 9409 amu. What is the percent abundance of lithium-6: one active ingredient in a herbicide has a density of 1. 70 g/cm3. In one sample of the herbicide formulation, 2. 0 g of the active ingredient are present in every 100. ml of the herbicide.
