Download CHEM193A FALL 2022-Exam1 GP Answer sheet

Exam #1
CHEM193A
General Chemistry I --- Fall 2022
9/26/2022
Instructor: Prof. G. Pantouris
Questions
32 multiple choice
(100 pts)
Find the correct answer (3.125 pts/question).
1. Which of the following represents a pair of isotopes?
a. 15N, 15O
b. 1H, 2He
c. 12C, 13Co
d. 31P, 31P3–
e. None of the above
2. Which among the following represent a set of isotopes if you know that the atomic nuclei
contain
I. 20 protons and 20 neutrons.
II. 21 protons and 19 neutrons.
III. 22 neutrons and 18 protons.
IV. 20 protons and 22 neutrons.
V. 21 protons and 20 neutrons.
a. I, V
b. III, IV
c. I, II, III
d. I, IV and II, V
e. No isotopes are indicated.
3. The ion 127I– has
a. 53 protons, 74 neutrons, 52 electrons
b. 53 protons, 74 neutrons, 54 electrons
c. 53 protons, 53 neutrons, 53 electrons
d. 53 protons, 74 neutrons, 53 electrons
e. 53 protons, 127 neutrons, 54 electrons
4. Which element does not belong to the family or classification indicated?
a. Br, halogen
b. Na, alkali metal
c. K, alkaline earth metal
d. He, noble gas
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5. What is the oxidation number of Al in Al(OH)4-?
a. +1
b. +2
c. +3
d. +4
6. Which is the correct formula of Zing oxide?
a. ZnO
a. ZnO2
b. Zn2O2
c. Zn2O
d. Zn2O3
7. ______ form ions with a + charge when they react with nonmetals.
a. Halogens
b. Noble gases
c. Alkaline earth metals
d. Alkali metals
e. None of these choices
8. Which of the following formulas is not correct?
a. Ba(OH)2
b. LiSO4
c. NaF
d. CsCl
e. MgI2
9. Which of the following is not the correct chemical formula for the name given?
a. FeI
b. BaBr2
c. Li2O
d. HF (g)
e. MgF2
iron(II) iodide
barium bromide
lithium oxide
hydrogen fluoride
magnesium fluoride
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10. Which of the following is not the correct name for the formula given?
a. HClO
b. Cr2S3
c. PCl5
d. CoO
e. CaSO3
hypochlorous acid
chromium(III) sulfide
phosphorus pentachloride
cobalt(II) oxide
calcium sulfate
11. For a new element, 60.54% is an isotope with mass 282.1 amu, 3.28% is an isotope with
mass 283.2 amu, and 36.18% is an isotope with mass 284.6 amu. Calculate the average
atomic mass of this new element.
a. 283.3 amu
b. 849.9 amu
c. 282.1 amu
d. 283.0 amu
e. 314.5 amu
12. The average mass of a X atom is 10.81. If you were able to isolate a single X atom, what is
the chance that you would randomly get an atom with mass 10.81?
a. greater than 50%
b. 0%
c. 0.81%
d. 10.81%
e. about 11%
13. A sample of iron weighing 15.0 g contains how many moles of iron atoms?
a. 3.72 mol
b. 0.269 mol
c. 0.118 mol
d. 0.577 mol
e. 0.0780 mol
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14. Find the identity of the element with a total mass of protons equal to 1.32 x 10-22 g
Note: Proton mass = 1.67 x 10-27 kg.
a. Pt
b. Li
c. Au
d. Pb
e. Ir
15. What is the molar mass of Glucose (C6H12O6)?
a. 178.16
b. 179.16
c. 180.16
d. 181.16
e. 182.16
16. For which of the following compounds does 1.0 g represent 2.27 × 10–2 mol?
a. H2O
b. C2H6
c. NH3
d. CO2
e. CO
17. Roundup, an herbicide manufactured by Monsanto, has the formula C3H8NO5P. How many
moles of molecules are there in a 500g sample of Roundup?
a. 84.5
b. 2.96
c. 0.338
d. 1.75
e. none of these
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18. Ammonia is formed by reacting nitrogen and hydrogen. If you know that 1.87 g of nitrogen
reacted with 0.4 g of hydrogen, find the correct statement:
a. Nitrogen is the limiting reactant
b. Hydrogen is the limiting reactant
c. In order to determine the limiting reactant you need to know the number of moles
d. Both nitrogen and hydrogen are in stoichiometric quantities
e. None of the above is correct
19. In the following reaction, which species is the reducing agent?
Cu + 2AgNO3 → Cu(NO3)2 + 2Ag
a. Ag+
b. Ag
c. Cu+
d. Cu
e. NO320. Calculate the molar mass of a sample if a single molecule weighs 5.34 × 10–23 g.
a. 12.0 g/mol
b. 5.34 × 10–23 g/mol
c. 1.13 × 1046 g/mol
d. 32.2 g/mol
e. none of these
21. A 17.2-g sample of HF is dissolved in water to give 3.1 × 102 mL of solution. The
concentration of the solution is
a. 5.5 M
b. 0.27 M
c. 5.3 M
d. 0.86 M
e. 2.8 M
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22. Which of the following statement(s) is/are correct for oxidation/reduction reactions?
a. In a small number of chemical reactions, oxidation occurs independently of the
reduction.
b. The element that gains electrons is called reducing agent because it gets reduced.
c. The balanced oxidation/reduction reaction should show the excess of electrons that
have not been captured by the oxidizing agent.
d. Only a and c are correct.
e. None of them is correct.
23. What volume of 2.0 M HCl can be prepared from 2.00 L of 9.00 M HCl?
a. 9.00 mL
b. 4.50 mL
c. 4.50 L
d. 9.00 L
e. none of these
24. Consider the following reaction in acidic environment
H2O2 + MnO4− → Mn2+ + O2 (g)
What is the oxidatation state of O found on the reactacts’ side?
a. -2
b. +2
c. 0
d. -1
e. +1
25. Which of the following solutions contains the greatest total ion concentration?
a. One mole of sodium phosphate dissolved in 1.0 L of solution.
b. One mole of potassium hydroxide dissolved in 1.0 L of solution.
c. One mole of iron(II) nitrate dissolved in 1.0 L of solution.
d. One mole of potassium chloride dissolved in 1.0 L of solution.
e. At least two of these solutions have an equal number of ions, and these contain the
greatest total ion concentration.
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26. How many grams of Na2SO4 are required to make 150.0 mL of a 0.180 M sodium sulfate
solution?
a. 3.40 g
b. 3.83 g
c. 3.21 g
d. 2.78 g
e. none of these
27. Which pair of ions would not be expected to form a precipitate when dilute solutions of each
are mixed?
a. Ni2+, SO42–
b. Ni2+, S2–
c. Cu2+, OH–
d. Co2+, PO43–
e. Ag+, Cl–
28. Lead(II) nitrate reacts with sodium chloride in aqueous solution to form a precipitate. What
is the net ionic equation for this reaction?
a. Na+(aq) + Cl2–(aq) → Na2Cl(s)
b. Na+(aq) + NO3–(aq) → NaNO3(s)
c. Pb2+(aq) + 2NO3–(aq) → Pb(NO3)2(s)
d. Na+(aq) + Cl–(aq) → NaCl(s)
e. Pb2+(aq) + 2Cl–(aq) → PbCl2(s)
29. When the equation C6H14 + O2 → CO2 + H2O is balanced with the smallest set of integers,
the sum of the coefficients is?
a. 28
b. 33
c. 47
d. 4
e. 40
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30. Consider the following unbalanced equation:
C4H10 + O2 → CO2 + H2O
For every 40 mol of C4H10, ___ mol of O2 is required.
a. 40
b. 180
c. 260
d. 380
e. none of these
31. Which acid will not dissociate fully in water?
a. HCl
b. NH3
c. HNO3
d. CH3COOH
e. none of these
32. True or False? Nonelectrolytes are insoluble in water.
a. True
b. False
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