Download CHEM102 Chemistry II Spring 10-11 Mid

CHEM102 Chemistry II Spring 10-11 Mid-term Exam/Faculty of Agricultural Sciences and Technologies
Student Registration No:___________________________________
Instructor: Prof.Dr.Hüseyin Oğuz
Student Name-Surname:___________________________________
Dept. of Computer Information Systems
Room#: CL006
Date: 08.04.2011/09:30-11:00
1) The scientific principle which is the basis for balancing chemical equations is
A) the Law of Conservation of Energy.
B) the Law of Conservation of Mass.
C) the Law of Conservation of Mass and Energy.
D) Avogadro's Law.
E) the Law of Definite Proportions.
1) B
2) The balanced equation for the reaction occurring when iron(III) oxide, a solid, is reduced with pure carbon to produce
carbon dioxide and molten iron is
2) C
A) 2 FeO3 + 3 C (s) → 2 Fe (l) + 3 CO2 (g).
B) 2 FeO + C (s) →? 2 Fe (l) + CO2 (g).
C) 2 Fe2O3 + 3 C (s) → 4 Fe (l) + 3 CO2 (g).
D) 4 Fe2O3 + 6 C (s) → 8 Fe (l) + 6 CO2 (g).
E) 2 Fe3O + C (s) → 6 Fe (l) + CO2 (g).
3) All of the statements regarding redox reactions are true except 3) B
A) metal ions are produced when pure metals are oxidized.
B) when a substance is oxidized its charge (or oxidation number) decreases.
C) halogens usually behave as oxidizing agents because they readily gain electrons.
D) a reducing agent causes another substance to be reduced.
E) alkali metals often behave as reducing agents because they readily lose electrons.
4) When a substance loses electrons it is ________; the substance itself is acting as a(an) ________ agent.
4) A
A) oxidized; reducing
B) dissolved; neutralizing
C) oxidized; oxidizing
D) reduced; oxidizing
E) reduced; reducing
5) Which statement based on the mole concept is not correct?
5) D
A) The number of atoms in one mole of platinum is the same as the number of atoms in one mole of uranium.
B) One mole of sodium chloride, NaCl, contains the same number of ions as one mole of calcium sulfate, CaSO4.
C) One mole of bromine, Br2, contains the same number of molecules as one mole of propane, C3H8.
D) One mole of methane, CH4, contains the same number of atoms as one mole of carbon dioxide, CO2.
E) The molar mass of a diatomic element is its atomic weight times two.
6) Which statement concerning the mole concept is not true?
6) C
A) The molar mass of a metal is its atomic weight expressed in grams.
B) One mole of sodium contains the same number of atoms as one mole of carbon.
C) One mole of any compound contains one mole of atoms.
D) The mole concept makes a connection between the mass of a substance and the number of particles or units of that
substance.
E) One mole of water contains the same number of molecules as one mole of ammonia.
7) How many molecules are present in 4.25 mol of CCl4? 7) A
A) 2.56 × 1024
B) 36.91
C) 153.81
D) 653.69
E) 9.26 × 1025
8) The oxidation number of iron in the compound FeBr3 is ________.
A) -2
B) +1
C) +3
D) -1
8) C
E) +2
9) Which reaction is an example of a precipitation reaction?
A) FeCl3 (aq) + KOH (aq) → Fe(OH)3 (s) + 3 KCl (aq)
9) A
B) H2CO3 (aq) → H2O (l) + CO2 (g)
C) 2 Hg (l) + O2 (g) → 2 HgO (s)
D) H2SO4 (aq) + Ca(OH)2 (aq) → CaSO4 (aq) + 2 H2O (l)
E) 6 HCl (aq) + 2 Al (s) → 2 AlCl3 (aq) + 3 H2 (g)
10) In a chemical reaction
10) C
A) the number of atoms depends present in a reaction can vary when the conditions change during the reaction.
B) there are equal numbers of molecules on each side of the reaction arrow.
C) there are equal numbers of atoms on each side of the reaction arrow.
D) there are always the same number of products as there are reactants.
E) none of the above
11) If heat is consumed during a reaction, the reaction is said to be ________.
A) endothermic
B) can't tell.
C) exothermic
D) exothermic
E) endergonic
12) Consider the reaction shown:
P4 (s) + 10 Cl2 (g) →
4 PCl5 (s) + 452 kcal
When 50.00 g of P4 react, ________ kcal will be ________. 12) C
A) 452; produced
B) 452; consumed
C) 182.4; produced
D) 729.7; produced
E) 182.4; consumed
13)
S + O2 → SO2
ΔH = -70.8 kcal
Based on the reaction shown, which statement is true?
13) E
A) 70.8 kcal are consumed when 32.1 g of sulfur reacts.
B) 70.8 kcal are produced when 1 g of sulfur reacts.
C) 70.8 kcal are produced when 1 g of sulfur dioxide is produced.
D) 70.8 kcal are consumed when 1 g of sulfur reacts.
11) A
E) 70.8 kcal are produced when 32.1 g of sulfur reacts.
14) A reaction is said to be ________ if the bonds formed during the reaction are stronger than the bonds broken. 14) C
A) endothermic
B) endergonic
C) exothermic
D) spontaneous
E) exergonic
15) When a reaction system is at equilibrium
15) B
A) there is no more chemistry happening.
B) the rates of the reaction in the forward and reverse directions are exactly equal.
C) the reaction rate in the forward direction is at a maximum.
D) the reaction rate in the reverse direction is at a minimum.
E) the amounts of reactants and products are exactly equal.
16) All of the statements regarding the symbol ΔG are true except
A) it allows us to predict the spontaneity of a reaction.
B) it allows us to identify an exothermic reaction.
C) it allows us to identify an endergonic reaction.
D) it refers to the free energy of the reaction.
E) it describes the effect of both enthalpy and entropy on a reaction.
16) B
17) The scientific principle which explains the observation that the amount of heat transfer accompanying a change in one
direction is numerically equal but opposite in sign to the amount of heat transfer in the opposite direction is
17) E
A) Avogadro's Law.
B) the Law of Conservation of Mass and Energy.
C) the Law of Conservation of Mass.
D) the Law of Definite Proportions.
E) the Law of Conservation of Energy.
18) Consider the reaction:
2 CO (g) +
(g)
2 CO2 (g)
The equilibrium expression for this reaction is
A)
B)
C)
D)
18) A
E)
19) What is the molarity of a solution prepared by dissolving 1.25 mol of AgNO3 in enough water to make 625 mL of
solution?
19) D
A) 0.500 M
B) 0.340 M
C) 0.00200 M
D) 2.00 M
E) 0.0118 M
20) How many grams of water are needed to prepare 250. g of a solution that is 5.00% by mass NaCl?
A) 245 g
B) 1250 g
C) 5.00 g
D) 238 g
E) 12.5 g
20) D
21) All of the water in a 0.200 M solution of NaCl was evaporated and 0.150 mole of NaCl was obtained. What was the
original volume of the sample? 21) A
A) 750. mL
B) 1000 mL (1.00 × 103 mL)
C) 1330 mL
D) 333 mL
E) 30.0 mL
22) How much NaOH is present in a 250. mL sample of a 5.00% (w/v) solution?
A) 5.00 g
B) 250 g C) 25.0 g
D) 10.0 g
E) 12.5 g
22) E
23) Which is not an example of a solution?
23) E
A) the mixture of gases in a SCUBA diving tank
B) a coin made from nickel and copper
C) antifreeze in a car radiator
D) spring water purchased at a supermarket
E) none of the above
24) How many grams of CaCl2 are needed to prepare 125 mL of a 1.50 M solution?
A) 1.69 g
B) 3.00 g
C) 20.8 g
D) 37.0 g
24) C
E) 0.188 g
25) Of the following four substances, which would form a basic solution when dissolved in water:
NH4Cl Cu(NO3)2
K2CO3 NaF
25) D
A) NH4Cl, Cu(NO3)2
B) NaF only
C) K2CO3, NH4Cl
D) NaF, K2CO3
E) none of them
26) Which of the following pH's corresponds to a strongly basic solution? 26) D
A) 4.3 B) 2.7 C) 7.4 D) 11.5 E) 6.9
27) A necessary requirement for a Brønsted base is
27) E
A) the production of hydronium ion upon reaction with water.
B) the presence of water as a reaction medium.
C) the presence of a metal ion in its formula.
D) the presence of hydroxide in its formula.
E) a lone pair of electrons in its Lewis dot structure.
28) Which example is not basic? 28) D
A) window cleaner
B) shampoo
C) Mg(OH)2, used in remedies for upset stomach
D) vinegar
E) limewater
29) Which of the following cannot act as a Brønsted base?
C) NH4+
D) CO32A) NH2B) HCO3-
29) C
E) NH3
30) What is the IUPAC name of the compound shown?
30) A
A) 3,5-dimethyloctane
B) 4-methyl-2-ethylheptane
C) 6-ethyl-4-methylheptane
D) 2-ethyl-4-methylheptane
E) 4,6-dimethyloctane
31) Which substance is not reactive with respect to alkanes?
A) O2
31) C
B) Cl2
C) H2
D) Br2
E) none of the above
32) Which of the following properties is not characteristic of alkanes?
A) They are generally less dense than water.
B) They are nontoxic.
C) They form strong hydrogen bonds.
D) Their melting points increase with molecular weight.
E) They are tasteless and colorless.
33) The condensed structure of 2,4-dimethyl-hexane is 33) A
A)
B) C
C)
D)
C
C
C
C
C
C
C
32) C
E)
34) The combination of ions most likely to produce a precipitate is
A) NH4+ and SO42-.
34) D
B) Mg2+ and C2H3O2-.
C) Pb2+ and NO3-.
D) Fe3+ and OH-.
E) Li+ and PO43-.
35) The molar mass of Fe(OH)3 is ________ g.
35) E
A) 74.88
E) 106.87
B) 72.86 C) 89.87 D) 104.86
36) How many molecules are there in 3.00 moles of NH3?
36) C
A) 3.00
B) 1.00
C) 1.81 × 1024
D) 1.20 × 1024
E) 17.00
37) All of the statements are true for spontaneous reactions except
37) D
A) the value of ΔG is less than zero.
B) they are said to be exergonic.
C) the value of ΔG is unaffected by a catalyst.
D) the reaction rate is determined by the value of ΔG.
E) if the enthalpy change is unfavorable, they occur at a high temperature.
38) For the following reaction, increasing the pressure will cause the equilibrium to ________.
2 SO2 (g) + O2 (g)
38) A
2 SO3 (g) + heat
A) shift to the right, towards products
B) remain unchanged, but the reaction mixture will get cooler
C) shift to the left, towards reactants
D) remain unchanged, but the reaction mixture will get warmer
E) Pressure has no effect on equilibrium.
39) How many mL of 14.5 M NH3 are needed to prepare 2.00 L of a 1.00 M solution?
A) 276 mL
B) 29.0 mL
C) 7.25 mL
D) 138 mL
39) D
E) 69.0 mL
40) What is the % (w/v) concentration of a solution containing 12 grams of solute in 400 mL of solution?
A) 12% B) 1.2% C) 4.0% D) 6.0% E) 3.0%
40) E
41) What is the concentration of a nitric acid solution if a 10.00 mL sample of the acid requires 31.25 mL of 0.135 M KOH
for neutralization?
41) B
A) 0.0432 M
B) 0.422 M
C) 0.844 M
D) 0.135 M
E) 0.211 M
42) Which of these, if dissolved in 1.0 L of pure water, would produce a buffer solution? 42) C
A) 0.1 mol H3O+ + 0.1 mol ClB) 0.1 mol H3O+ + 0.1 OHC) 0.1 mol NaH2PO4 + 0.1 mol Na2HPO4
D) 0.1 mol HCl + 0.1 mol NaOH
E) 0.1 mol NaCl + 0.1 mol KCl
43) The name of the following structure will end with the following parent name:
43) E
A) petane
B) ethane
C) octane
D) hexane
E) butane
44) The balanced equation given below means:
CH4
+
2O2
→
CO2
+
2H2O
44) E
A) One molecule of methane reacts with two molecules of oxygen to produce one molecule of carbon dioxide and two
molecules of water.
B) One gram of methane reacts with two grams of oxygen to produce one gram of carbon dioxide and two grams of
water.
C) One mole of methane reacts with two moles of oxygen to produce one mole of carbon dioxide and 2 moles of water.
D) A, B and C are correct.
E) A and C are correct.
45) A reaction that is spontaneous can be described as 45) E
A) having the same rate in both the forward and reverse directions.
B) releasing heat to the surroundings.
C) increasing in disorder.
D) proceeding in both the forward and reverse directions.
E) proceeding without external influence once it has begun.
46) All of the statements about molarity are correct except
46) C
A) volume = moles/molarity.
B) the abbreviation is M.
C) the interpretation of the symbol is "moles of solute per mole of solvent."
D) moles = molarity × volume .
E) the molarity of a diluted solution is less than the molarity of the original solution.
47) Which of the following solutions is a buffer? 47) C
A) a solution of hydrochloric acid and sodium acetate
B) a solution of acetic acid and sodium sulfate
C) a solution of acetic acid and sodium acetate
D) a solution of hydrochloric acid and sodium sulfate
E) a solution of sulfuric acid and sodium sulfate
48) What is the IUPAC name of the compound shown?
48) C
A) isooctane
B) 2-methyl-2-propylbutane
C) 3,3-dimethylhexane
D) 2-ethyl-2-methylpentane
E) 2,2-ethyl-methylpentane
49) The molar mass of butane, C4H10, is ________ grams.
A) 68.24
B) 22.01 C) 52.08 D) 49.05
49) E
E) 58.12
50) Activation energy can best be described as 50) D
A) the energy level of the reactants.
B) the energy level of the products.
C) the difference in energy between reactants and products.
D) the difference in energy between reactants and the maximum energy.
E) the maximum energy level of the reaction.