Chem II Test 4
What is the rate for the first order reaction A → Products when [A] = 0.201 M? (k = 0.360 1/min)
0.0724 M/min
The OH⁻ concentration in an aqueous solution at 25 °C is 7.9 × 10⁻³. What is [H⁺]?
1.26x10-12
The pOH of an acidic solution is 10.29. What is [H⁺]?
1.9x10^-4
What is the overall reaction order for the following rate law: Rate = k[A][B][C]²
4
Consider the radioisotope ²³⁵U (half life = 7.04 × 10⁸ years). What is the first order rate constant for ²³⁵U?
9.84 × 10⁻¹⁰ 1/years
Which of the following molecules is a tertiary alcohol?
A
The second law of thermodynamics states that _____
All are true
Which of the following molecules is a primary alcohol?
C
What intermolecular forces are present in both molecules of CH₃CH₂OH and CH₃CH₂NH₂?
Dispersion forces, dipole-dipole forces, and hydrogen bonding.
What is the oxidizing agent in the reaction Zn + 2 H⁺ → Zn²⁺ + H₂?
H+
What are the units for the rate constant of a first-order reaction?
S-1
Ammonia and hydrogen fluoride both have unusually high boiling points due to _____
hydrogen bonding
The reaction rate of a reaction at 60 °C will be greater than at 30°C because _____
there is a greater proportion of reactants with the necessary kinetic energy to react.
For the reaction 2 A + 3 B → 4 D + 5 E, how is the rate of reaction expressed in terms of rate of disappearance of B?
-1/3∆[B]/∆t
Calculate ∆S° for C₃H₄(g) + 2 H₂(g) → C₃H₈(g).
-258.2 J/mol ･ K
Calculate ∆S° for NH₃(g) + HCl(g) → NH₄Cl(s).
-284.6 J/mol ･ K
The oxidation number of the phosphorus atom in P³⁻ is
-3
Calculate ∆S° for C(g) + 2 H₂(g) → CH₄(g).
-80.7 J/mol ･ K
The common feature of all carboxylic acids is the presence of a _____
-C(=O)OH group
The common feature of all carboxylic acids is the presence of a _____
-C(=O)OH group.
The common feature of all esters is the presence of a _____
-C(=O)OR group
Considering the Arrhenius equation, what is the slope of a plot of ln k versus 1/T equal to?
-Ea/R
What ending in the name of a compound indicates it is a ketone?
-one
The oxidation number of chlorine in Cl₂ is
0
What is the half-life for a particular reaction if the rate law is rate = (1301 M⁻¹*min⁻¹)[A]² and the initial concentration of A is 0.250 M?
0.00307 min
The zero order reaction A → Products takes 63.5 minutes for the concentration of A to decrease from 0.970 M to 0.205 M. What is the value of k for this reaction?
0.0120
What is the rate for the first order reaction A → Products when [A] = 0.201 M? (k = 0.360 1/min)
0.0724 M/s
The second order reaction A → Products takes 13.5 s for the concentration of A to decrease from 0.740 M to 0.205 M. What is the value of k for this reaction?
0.261 M⁻¹s⁻¹
What is the concentration of A after 10.5 minutes for the zero order reaction A → Products when the initial concentration of A is 0.400 M? (k = 0.00762 M/min)
0.319 M
Consider the following redox reaction: Ag⁺(aq) + Fe²⁺(aq) ⇌ Ag(s) + Fe³⁺(aq). How many moles of electrons are exchanged?
1
The half-life for the second order reaction A → Products is 4.57 min. What is the value of the rate constant for the reaction if the initial concentration of A is 0.205?
1.07 M⁻¹min⁻¹
The concentration of the hydronium ion in an aqueous solution at 25 °C is 0.0092 M. What is the concentration of the hydroxide ion?
1.096x10-12
The radioisotope ¹⁴C (half life = 5730 years) is used for carbon dating. What is the first order rate constant for ¹⁴C?
1.2x10-4
Consider the equilibrium system described by the chemical reaction below. At equilibrium, a 1.5 L reaction vessel contained a mixture of 5.0 × 10⁻² M SO₃, 3.5 × 10⁻³ M O₂, and 3.0 × 10⁻³ M SO₂ at 800 K. What are the values of Kc and Kp for the reaction at this temperature?
1.2x10^3
What is the absolute magnitude of the rate of change for [NH₃] if the rate of change for [H₂] is 2.00 M/s in the reaction 2 NH₃(g) → N₂(g) + 3 H₂(g)?
1.34
What is the absolute magnitude of the rate of change for [NH₃] if the rate of change for [H₂] is 2.00 M/s in the reaction 2 NH₃(g) → N₂(g) + 3 H₂(g)?
1.34 M/s
The activation energy, Ea, for a particular reaction is 19.4 kJ/mol. If the rate constant at 80 °C is 0.820 M⁻¹s⁻¹, then what is the value of the rate constant at 121 °C? (R = 8.314 J/mol • K)
1.63 M⁻¹s⁻¹
Complete and balance the following redox reaction in acidic solution.
10 ClO₃⁻(aq) + I₂(s) + 8 H⁺(aq) → 10 ClO₂(g) + 2 IO₃⁻(aq) + 4 H₂O(l)
What amount of time is required for the concentration of A to decrease from 0.800 M to 0.200 M in the zero-order reaction A → B? (k = 0.0567 M*s⁻¹)
10.6 sec
For cyclohexane, the ∆H° of vaporization is 33.10 kJ/mol and the ∆S° of vaporization is 111.80 J/mol･K. At 1.00 atm and 201 K, what is the ∆G° of vaporization for cyclohexane, in kJ/mol?
10.628 J/molxK
What is the pH of a solution of 0.400 M CH₃NH₂ containing 0.250 M CH₃NH₃I? (Kb of CH₃NH₂ is 4.4 × 10⁻⁴)
10.85
What is the pH of a 0.00100 M solution of NaOH?
11
The pOH of a basic solution is 2.75. What is pH?
11.25
Complete and balance the following redox reaction in acidic solution
16 H⁺(aq) + 2 MnO₄⁻(aq) + 10 S₂O₃²⁻(aq) → 5 S₄O₆²⁻(aq) + 2 Mn²⁺(aq) + 8 H₂O(l)
How many covalent bonds does oxygen typically form in an organic compound?
2
hat is the IUPAC name for the alcohol shown here?
2,4-dimethyl-1-pentanol
Name the following using correct IUPAC nomenclature:
2- mehtylbutane
What is the correct IUPAC name for the compound shown here?
2-methyl-1-propanol
What is the correct IUPAC name for the compound shown here?
2-methyl-3-pentanol
How long will it take for the concentration of A to decrease from 1.25 M to 0.205 for the second order reaction A → Products? (k = 1.52 M⁻¹min⁻¹)
2.68 min
How many carbon-carbon double bonds are present in the structure of ibuprofen shown?
3
The oxidation number of C in C₂O₄²⁻ is
3
For propane, the ∆H° of vaporization is 22.9 kJ/mol and the ∆S° of vaporization is 99.0 J/mol･K. At 1.00 atm and 201.0 K, what is the ∆G° of vaporization for propane, in kJ/mol?
3.00 kJ/mol
The pOH of a solution is 3.45. What is the OH⁻ concentration in the solution?
3.5 × 10⁻⁴ M
What is the rate for the zero order reaction A → Products when [A] = 0.200 M? (k = 3.57 M/min)
3.57 M/min
The half-life for the zero order reaction A → Products is 276 s. What is the value of the rate constant for the reaction if the initial concentration of A is 0.205?
3.71 × 10⁻⁴ M/s
The number of covalent bonds carbon forms in organic compounds is ____.
4
The oxidation number of Mn in MnO₂ is
4
What is the oxidation number of S in the compound Na₂S₂O₅?
4
What is the oxidation number of the carbon atom in CO₂?
4
For the reaction 2 A + 4 B → 2 C + 4 D, what is the absolute magnitude of the rate of change for [B] when [C] is increasing at 2.0 M/s?
4.0 M/s
In an aqueous solution at 25°C, if [H₃O⁺] = 2.4 × 10⁻⁴ M, then [OH⁻] is
4.2x10-11
A reaction was shown to follow second-order kinetics. How much time is required for [A] to change from 0.500 M to 0.250 M? (k = 0.456 M⁻¹ s⁻¹)
4.38 sec
The activation energy, Ea, for a particular reaction is 13.6 kJ/mol. If the rate constant at 754 °C is 24.5/min, at what temperature (in °C) will the rate constant be 10.7/min? (R = 8.314 J/mol • K)
403
The following reaction 2CO(g) + Br₂(g) → 2COBr(g) has the rate law, rate = k[CO] [Br₂]³. The overall order of this reaction is
4th
What is the smallest whole-number coefficient for H₂S when the equation H₂S + MnO₄⁻ → Mn²⁺ + SO₄²⁻ is balanced in acidic solution?
5
he oxidation number on the nitrogen in NO₃⁻ is
5
What is the half-life for a particular reaction if the rate law is rate = (1301 min⁻¹)[A]?
5.33 × 10⁻⁴ min
The pH of an acidic solution is 4.77. What is [OH⁻]?
5.9x10-10
How many carbon atoms are present in 3-methylpentane?
6
How many electrons are exchanged in the following reaction? 2 Fe³⁺(aq) + 3 Cu(s) ⇌ 2 Fe(s) + 3 Cu²⁺(aq)
6
What is the oxidation number on the sulfur atom in SO₄²⁻?
6
A first order reaction initially contains 1.00 × 10²⁰ molecules. If the reaction has a half-life of 20.0 minutes, how many molecules remain unreacted after 80.0 minutes?
6.25 × 10¹⁸ molecules
The oxidation number of Cl in HClO₄ is
7
The oxidation number of the manganese atom in MnO₄⁻ is
7
The pH of an acidic solution is 2.11. What is [H⁺]?
7.8 × 10⁻³ M
The pH of a basic solution is 8.11. What is [H⁺]?
7.8x10-9
Complete and balance the following redox reaction in acidic solution
8 H⁺(aq) + 3 H₂O₂(aq) + Cr₂O₇²⁻(aq) → 3 O₂(g) + 2 Cr³⁺(aq) + 7 H₂O(l)
The activation energy for a particular reaction is 102 kJ/mol. If the rate constant is 1.35 × 10⁻⁴ s⁻¹ at 308 K, what is the rate constant at 273 K?
8.18 × 10⁻⁷ 1/s
Which of the following is the correct expression for the concentration based equilibrium constant for the reaction: Mg(OH)₂ (s) ⇌ Mg²⁺ (aq) + 2 OH⁻ (aq)
A
Which of the following statements best described Le Chatelier's Principle?
A reaction which is at equilibrium, when disturbed, will react appropriately to reestablish equilibrium.
In the following chemical reaction, which element is the reducing agent? 2 IO₃⁻(aq) + 12 H⁺(aq) + 10 Ag(s) + 10 Cl⁻(aq) → 10 AgCl(s) + I₂(s) + 6H₂O(l)
Ag
The second law of thermodynamics states that _____
All of these are true
Which of the following molecules is unsaturated?
B
In the following reaction, which element in what species is oxidized? C₂H₄ (g) + 3 O₂ (g) → 2 CO₂ (g) + 2 H₂O (g)
C in C2H4
What is the formula of an alkane with 18 carbon atoms?
C18H38
The common feature of aldehydes and ketones is the presence of a
C=O group
The common feature of aldehydes and ketones is the presence of a _____
C=O group
Consider the following reaction in the forward direction. Identify the base: CH₃CH₂OH + HCl ⇌ CH₃CH₂OH₂⁺ + Cl⁻
CH₃CH₂OH
Which one of the following correctly ranks the compounds in order of lowest vapor pressure to highest vapor pressure based only in intermolecular forces?
CH₃CH₂OH < CH₃OCH₃ < CH₃CH₂CH₃
Predict the conjugate base of CH₃CH₂OH.
CH₃CH₂O⁻
Which of the following reactions would have the most positive ∆S° value?
CO₂(s) ⟶ CO₂(g)
Construct the expression for Kc for the following reaction. CH4 + 2H2S= CS2 + 4H
CS2 x H^4 / CH4 x H2S^2
Which compound contains chlorine (Cl) with an oxidation number of +3
Cl2O3
Complete and balance the following redox reaction in acidic solution.
Cr₂O₇²⁻(aq) + 3 Pb²⁺(aq) + 2 H⁺(aq) → 2 Cr³⁺(aq) + 3 PbO₂(s) + H₂O(l)
Which of the following molecules is an ester?
D
A compound such as CH₃CH₂CH₂OCH₂CH₃ is classified as what type of organic compound?
Ether
In the redox reaction 6 Fe²⁺ + Cr₂O₇²⁻ + 14 H⁺ → 2 Cr³⁺ + 6 Fe³⁺ + 7 H₂O, what is the reducing agent?
Fe2+
What is the order of the reaction if A decomposes to B and C with a rate constant of 8.43 × 10⁻⁴ s⁻¹ at a certain temperature?
First
In the following reaction, which element in what species is reduced? Zn (s) + 2 HCl (aq) → ZnCl₂ (aq) + H₂ (g)
H in HCl
Which of the following has the largest standard molar entropy, S° (298.15 K)?
H2 (g)
Choose the compound with the largest standard molar entropy, S° (298.15 K).
H20 (g)
Write the formula of the conjugate acid of the Brønsted-Lowry base, ClO⁻
HClO
Which choice incorrectly identifies the oxidation number (O.N.) for the given species?
H₂, O.N. = +1
Write the formula of the conjugate acid of the Brønsted-Lowry base, HCO₃⁻
H₂CO₃
Which of the following phase changes is not spontaneous at room temperature? Assume only the first phase is initially present.
H₂O(g) → H₂O(s)
Which of the following processes has a negative ∆S?
H₂O(g) → H₂O(s)
Which of the following are spontaneous processes? 1. Ice melting at 273 K (assume only ice is initially present). 2. Heat flowing from a hot object to a cold object. 3. An iron bar rusting.
I II and III
Which of the following substances would have the greatest dispersion forces?
I2
Which of the following would have zero entropy? I. O₂(g) at 273 K II. amorphous SiCN(s) at 1 K III. KBr(s, perfect crystal) at 10 K IV. Li(s, perfect crystal) at 0 K
IV only
Which of the following is true about the total entropy of the universe?
It is always increasing
Which of the following is true about all spontaneous processes?
It will continue on its own once begun
Which of the following substances would not exhibit any hydrogen bonding interactions in a pure substance?
N(CH₃)₃
Construct the expression for Kc for the following reaction. 3NO=N20+NO2
N2OxNO2/NO3
Write the formula of the conjugate base of the Brønsted-Lowry acid, NH₄⁺
NH3
Which of the following reactions would have the most negative ∆S° value ?
NH₃(g) + HBr(g) ⟶ NH₄Br(s)
What will the sign on ∆S be for the following reaction and why? 2 Mg (s) + O₂ (g) → 2 MgO (s)
Negative, because there are more moles of gas on the reactant side than the product side
What will the sign on ∆S be for the following reaction and why? 2 Mg (s) + O₂ (g) → 2 MgO (s)
Negative, because there are more moles of gas on the reactant side than the product side.
Which species has the greatest rate of disappearance in the reaction below? CH₄ + 2 O₂ → 2 CO₂ + H₂O
O2
Which species has the greatest rate of appearance in the reaction below? 2 H₂S + O₂ → 2 S + 2 H₂O
S and H₂O have identical rates
In which of the following species does sulfur have the lowest oxidation number?
S2-
Which of the following is true for a perfect crystal at absolute zero?
S=0
Which of the following best describes the third law of thermodynamics?
S° = 0 for perfect Li(s) at 0 K
Copper roofs on houses form patina (copper carbonates) over the course of years due to the reaction with oxygen, carbon dioxide and water in the air. Which of the following statements is incorrect for this process?
The reaction has a low activation energy.
Which law states that the entropy of a perfect crystalline substance is zero at the absolute zero of temperature?
Third law of thermodynamics
Which of the following equations describes the calculation for the half-life of a zero-order reaction?
[A]₀/2k
Which of the following affects the collision rate of molecules in the gas phase?
all of these
Which of the following molecules is a carboxylic acid?
compound c
For an exothermic reaction, an increase in temperature will
decrease the value of the equilibrium constant.
What is the effect on k as the activation energy for a reaction increases?
decreases
What intermolecular forces are mostly responsible for the melting point and boiling point of an alkene?
dispersion
Which of the following represents the intermolecular forces present in CO₂?
dispersion only
Identify the type or types of intermolecular forces present between molecules of the compound pictured below:
dispersion, dipole-dipole, and hydrogen bonding
What order of reaction has a half life equation of t½ = 0.693/k?
first
The high boiling points and water solubility for smaller amides is due to what intermolecular force?
hydrogen bonding
As a pure substance, which of the following could experience dipole-dipole interactions? I. CO₂ II. HCl III. CCl₄
ii only
Which best explains why the trend in noble gas boiling points increases down the group?
increasing dispersion interactions
NaOH is a Brønsted-Lowry base because
its a proton acceptor
-C(=O)OR group
ketone
An alkyne contains a triple bond between two carbon atoms. In a triple bond there is one sigma bond and two pi bonds. The pi bond is formed by the overlap of which orbitals?
p
Consider the following reaction at equilibrium CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g) If CO(g) is removed, in which direction will the equilibrium shift?
reactants
A solution has a pOH of 7.84. This tells us
slightly acidic
Determine the hybridization of the indicated carbon in the alkene shown here.
sp2
Consider the following chemical reaction at equilibrium: CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g) If H₂ is removed, how will Keq for the reaction change?
stay the same
If the reaction quotient (Q) is equal to the equilibrium constant (K) for a reaction then
the reaction is at equilibrium and the reaction will proceed at equal rates in the reverse and forward direction.
Isomers have ______________
the same molecular formula but different structure
Which law states that the entropy of a perfect crystalline substance is zero at the absolute zero of temperature?
third law of thermodynamics
Which of the following best describes the reaction? 2 H₂S(g) + 3 O₂(g) → 2 H₂O(g) + 2 SO₂(g)
∆S° has a small negative value.