1101-1st Midterm Exam_11/03/21_(A)
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Which of the following is an illustration of the law of constant composition?
A) Water is 11% hydrogen and 89% oxygen by mass.
B) Water is a compound.
C) Water can be separated into other substances by a chemical process.
D) Water and salt have different boiling points.
E) Water boils at 372 K at 101.325 kPa pressure.
Answer: A
2) Which of the following are chemical processes?
1. rusting of a nail 2. freezing of water
3. decomposition of water into hydrogen and oxygen gases 4. compression of oxygen gas
A) 1, 2 B) 2, 3, 4 C) 1, 3 D) 1, 4 E) 1, 3, 4
Answer: C
3) Accuracy refers to ________.
A) how close a measured number is to other measured numbers B) how close a measured number is to the calculated value C) how close a measured number is to zero
D) how close a measured number is to infinity E) how close a measured number is to the true value Answer: E
4) Which one of the following is an intensive property?
A) temperature B) length C) amount D) volume E) mass
Answer: A
5) What would be the volume of a box that measures 1.12 m × 1.00 m × 0.69 m?
A) 0.7728 B) 0.77 C) 0.773 D) 0.772800 E) 0.77280
Answer: B
6) Consider the following selected postulates of Dalton's atomic theory:
(i) Each element is composed of extremely small particles called atoms.
(ii) Atoms are indivisible.
(iii) Atoms of a given element are identical.
(iv) Atoms of different elements are different and have different properties.
Which of the postulates is(are) no longer considered valid?
A) (iii) and (iv) B) (ii) only C) (iii) only D) (ii) and (iii) E) (i) and (ii) Answer: D
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7) The charge on an electron was determined in the ________.
A) cathode ray tube, by J. J. Thomson B) Millikan oil drop experiment C) Dalton atomic theory
D) Rutherford gold foil experiment E) atomic theory of matter
Answer: B
8) Which isotope has 36 electrons in an atom?
A) 3680Hg B) 7834Se C) 8036Kr D) 8035Br E) 3417Cl
Answer: C
9) The element X has three naturally occurring isotopes. The isotopic masses (amu) and % abundances of the isotopes are given in the table below. The average atomic mass of the element is ________ amu.
Isotope Abundance Mass
159X 30.60 159.37
163X 15.79 162.79
164X 53.61 163.92
A) 161.75 B) 163.15 C) 162.35 D) 162.03 E) 33.33
Answer: C
10) Which formula/name pair is incorrect?
A) Fe2(SO3)3 iron(III) sulfite B) Fe2(SO4)3 iron(III) sulfide C) FeSO4 iron(II) sulfate D) FeS iron(II) sulfide E) FeSO3 iron(II) sulfite Answer: B
11) Which of the following compounds would you expect to be ionic?
A) H2O B) CO2 C) SrCl2 D) H2S E) SO2
Answer: C
12) Which of the following are combustion reactions?
1) CH4 (g) + O2 (g) CO2 (g) + H2O (l) 2) CaO (s) + CO2 (g) CaCO3 (s) 3) PbCO3 (s) PbO (s) + CO2 (g)
4) CH3OH (l) + O2 (g) CO2 (g) + H2O (l)
A) 1, 3, and 4 B) 3 and 4 C) 1 and 4 D) 2, 3, and 4 E) 1, 2, 3, and 4 Answer: C
13) Calculate the percentage by mass of oxygen in Pb(NO3)2.
A) 19.3 B) 9.7 C) 33.4 D) 14.5 E) 29.0
Answer: E
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14) What is the total number of atoms in 0.139 mol of Fe(OH2)63+?
A) 19.0 B) 1.84 × 1024 C) 8.37 × 1022 D) 1.59 × 1024 E) 2.64
Answer: D
15) Balance the following reaction and determine the coefficient of potassium hydroxide.
K (s) + H2O (l) KOH (aq) + H2 (g)
A) 1 B) 2 C) 3 D) 4 E) 5
Answer: B
16) Combustion of a 0.9827-g sample of a compound containing only carbon, hydrogen, and oxygen produced 1.900 g of CO2 and 1.070 g of H2O. What is the empirical formula of the compound?
A) C5H7O3 B) C4H11O2 C) C2H5O D) C2H5O2 E) C4H10O
Answer: B
17) Lithium and nitrogen react in a combination reaction to produce lithium nitride:
6Li (s) + N2 (g) 2Li3N (s)
How many moles of lithium are needed to produce 0.45 mol of Li3N when the reaction is carried out in the presence of excess nitrogen?
A) 0.30 B) 0.23 C) 0.15 D) 1.35 E) 2.7
Answer: D
18) Lead (II) carbonate decomposes to give lead (II) oxide and carbon dioxide:
PbCO3 (s) PbO (s) + CO2 (g)
If the reaction yield is 92.4%, how many grams of lead (II) oxide will be produced by the decomposition of 1.30 g of lead (II) carbonate?
A) 1.41 B) 1.18 C) 1.20 D) 1.00 E) 1.09
Answer: D
19) The net ionic equation for formation of an aqueous solution of Al(NO3)3 via mixing solid Al(OH)3 and aqueous nitric acid is ________.
A) Al(OH)3 (s) + 3HNO3 (aq) 3H2O (l) + Al3+ (aq) + NO3- (aq) B) Al(OH)3 (s) + 3HNO3 (aq) 3H2O (l) + Al(NO3)3 (aq) C) Al(OH)3 (s) + 3NO3- (aq) 3OH- (aq) + Al(NO3)3 (s) D) Al(OH)3 (s) + 3NO3- (aq) 3OH- (aq) + Al(NO3)3 (aq)
E) Al(OH)3 (s) + 3H+ (aq) 3H2O (l) + Al3+ (aq) Answer: E
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20) Which combination will produce a precipitate?
A) Cu(NO3)2 (aq) and KC2H3O2 (aq) B) KOH (aq) and HNO3 (aq)
C) AgC2H3O2 (aq) and HC2H3O2 (aq) D) NaOH (aq) and Sr(NO3)2 (aq)
E) Pb(NO3)2 (aq) and HCl (aq) Answer: E
21) In which reaction does the oxidation number of hydrogen change?
A) HCl (aq) + NaOH (aq) NaCl (aq) + H2O (l) B) SO2 (g) + H2O (l) H2SO3 (aq)
C) 2Na (s) + 2H2O (l) 2NaOH (aq) + H2 (g)
D) 2HClO4 (aq) + CaCO3 (s) Ca(ClO4)2 (aq) + H2O (l) + CO2 (g) E) CaO (s) + H2O (l) Ca(OH)2 (s)
Answer: C
22) Which of the following are weak electrolytes?
HNO3HF NH3 LiBr
A) HNO3, HF, NH3, LiBr B) HNO3, NH3, LiBr C) HF, NH3
D) HNO3, LiBr E) HF, LiBr Answer: C
23) How many moles of K+ are present in 343 mL of a 1.27 M solution of K3PO4?
A) 3.70 B) 0.145 C) 1.31 D) 0.436 E) 11.1
Answer: C
24) The molarity (M) of an aqueous solution containing 85.1 g of sucrose (C12H22O11) in 128 mL of solution is ________.
A) 665 B) 0.665 C) 0.0019 D) 0.249 E) 1.94
Answer: E
25) A 31.5 mL aliquot of HNO3 (aq) of unknown concentration was titrated with 0.0134 M NaOH (aq).
It took 23.9 mL of the base to reach the endpoint of the titration.
The concentration (M) of the acid was ________.
A) 0.0204 B) 0.0102 C) 0.0051 D) 1.02 E) 0.227
Answer: B
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