C II E II
most common types of heterogeneous catalysts
solids
express the rate of reaction in terms of the change in concentration
-delta a/ delta t = 1/2
factors that affect the ease with which a proton is released from nonmetal hydride
-the strength of the E -H bond-the electronegativity of the central atom
Cyclopropane is converted to propene in a first-order process. The rate constant is 5.4 × 10-2 hr-1. If the initial concentration of cyclopropane is 0.150 M, what will its concentration be after 22.0 hours?
0.0450
Given the following equilibrium data at a particular temperature: 2 NO2Cl (g) <==> 2 NO2 (g) + Cl2 (g)[NO2Cl] = 0.019M, [NO2] = 0.041M, and [Cl2] = 0.037M calculate the value of Kc for the reaction at this temperature.
0.17Kc = [(0.041)^2 (0.037)]/ [(0.019)^2] = 0.17
Place the steps necessary to determine reaction order from an integrated rate law in the correct order, starting with the first step at the top of the list.
1 Rearrange each rate law into an equation for a straight line (y=mx+b) 2 Plot y vs. x for each integrated rate law. 3 The linear plot indicates the order of reaction.
N2(g) + O2(g) 2NO(g) Kc = 4.8 × 10-312NOBr(g) 2NO(g) + Br2(g) Kc = 0.50 Given the above equilibrium constant data at 25°C, what is the value of Kc at this temperature for the reaction 2NOBr(g) N2(g) + O2(g) + Br2(g)?
1.0 x 10 ^30
Hydrogen sulfide will react with water as shown in the following reactions.H2S(g) + H2O(l) H3O+(aq) + HS-(aq) K1 = 1.0 × 10-7HS-(aq) + H2O(l) H3O+(aq) + S2-(aq) K2 = ?H2S(g) + 2H2O(l) 2H3O+(aq) + S2-(aq) K3 = 1.3 × 10-20What is the value of K2?
1.3 x 10^13
Butyric acid is responsible for the odor in rancid butter. A solution of 0.25 M butyric acid has a pH of 2.71. What is the Ka for the acid?
1.5 × 10-5
The rate law for the reaction 3A → 2B is rate = k[A] with a rate constant of 0.0447 hr-1. What is the half-life of the reaction?
15.5 hours
Ammonia will react with oxygen in the presence of a copper catalyst to form nitrogen and water. From 164.5°C to 179.0°C, the rate constant increases by a factor of 4.27. What is the activation energy of this oxidation reaction?
165 kJ/mol
Consider the reactions of cadmium with the thiosulfate anion. Cd2+(aq) + S2O32-(aq) Cd(S2O3)(aq) K1 = 8.3 × 103 Cd(S2O3)(aq) + S2O32-(aq) Cd(S2O3)22-(aq) K2 = 2.5 × 102What is the value for the equilibrium constant for the following reaction? Cd2+(aq) + 2S2O32-(aq) Cd(S2O3)22-(aq)
2.1 x 10^6
Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution. H+ + H2O2 H2O+-OH (rapid equilibrium)H2O+-OH + Br- → HOBr + H2O (slow) HOBr + H+ + Br- → Br2 + H2O (fast) What is the overall reaction equation for this process?
2H+ + 2Br- + H2O2 → Br2 + 2H2O
Consider the equilibrium reaction shown below.B2(g) 2B(g)If the rate constants are: kfwd = 7.00 × 10-5s-1 and krev = 2.00 × 10-5 L mol-1 s-1, what is the value of Kc under these conditions?
3.5
Formic acid, which is a component of insect venom, has a Ka = 1.8 × 10-4. What is the [H3O+] in a solution that is initially 0.10 M formic acid, HCOOH?
4.2 × 10-3 M
What is the [H3O+] for a solution at 25°C that has pOH = 5.640?
4.37 × 10-9 M
Sulfur trioxide can undergo decomposition according to the equation 2SO3 → 2SO2 + O2 For this reaction, rate = -0.5Δ[SO3 ]/Δt = k[SO3]2. If the reaction rate is 1.75 × 10-7 mol L-1 min-1 when the concentration of sulfur trioxide is 5.4 × 10-3 mol L-1, what is the value of the rate constant k?
6.0 × 10-3 L mol-1 min-1
Consider the reversible reaction: 2NO2(g) N2O4(g)If the concentrations of both NO2 and N2O4 are 0.016 mol L-1, what is the value of c?
63
Nitric oxide is formed in automobile exhaust when nitrogen and oxygen in air react at high temperatures. N2(g) + O2(g) 2NO(g) The equilibrium constant Kp for the reaction is 0.0025 at 2127°C. If a container is charged with 8.00 atm of nitrogen and 5.00 atm of oxygen and the mixture is allowed to reach equilibrium, what will be the equilibrium partial pressure of nitrogen?
7.8 atm
A gas-phase decomposition is first-order with respect to the reactant, R. If the initial concentration of R is 1.0 × 10-4 mol L-1 and the rate constant k = 1.08 × 10-6 s-1, what concentration of R remains after 25 days?
9.7 × 10-6 mol L-1
Which of the following statements correctly describe a reaction mechanism? Select all that apply.
A reaction mechanism describes a series of single reaction steps that sum to the overall chemical equation. A reaction mechanism is a hypothesis
Calcium oxide, CaO, also known as quick lime, will react with carbon dioxide to form calcium carbonate, CaCO3. Which species, if any, acts as a Lewis acid in the reaction?
CO2
Which of the following correctly reflect ways in which a chemical equilibrium can be disturbed? Select all that apply.
Changing the concentrations of reactants or products Changing the temperature of the system Changing the volume of the reaction container for a reaction involving gases
What is an elementary step?
Each step that makes up a reaction mechanism
A reaction intermediate is a species corresponding to a local energy maximum on a reaction energy diagram
False
In a reversible reaction, a catalyst will speed up the forward reaction but not affect the reverse reaction.
False
1.9 moles of hi are added to an evacuated
H2 = +x; I2 = x Kc= 1.26 x 10^-3 = (0.19 2-x)^2/ x^2 HI= 0.19 M
Select the net ionic equation for the reaction between sodium chloride and mercury(I) nitrate. 2NaCl(aq) + Hg2(NO3)2(aq) → 2NaNO3(aq) + Hg2Cl2(s
Hg2^2+ (aq) + 2Cl- (aq) yields Hg2Cl2 (s)
which of the following best describes the effect of reactant concentration on reaction rate
Higher concentrations result in more effective collisions therefore increasing rate of a reaction.
Which, if any, of the following is an example of the leveling effect?
In water, no acid stronger than H3O+ can exist
How does the equilibrium constant change when all the coefficients of a balanced equation are multiplied by the same factor?
K'= K^n, where n is the factor by which the coefficient are multiplied
The two general types of weak base include molecules that contain one or more __ atoms, and the anions of weak ______.
N, acids
limits how fast an overall reaction proceeds; the rate law of the rate determining step becomes the rate law for the overall reaction.
Rate-determining step
Which of the following statements accurately describe Bronsted-Lowry acid-base reactions?
Some species can act as either an acid or a base depending on the other species present. The reactants and products contain an acid and a base.
For the following reaction, what will be observed if the volume is increased at constant temperature? Select all that apply.2NO2 <-> 2NO + O2
The concentration of all species will decrease at the instant the volume is changed. The equilibrium position will shift toward the products.
The substance NH3 is considered
a weak base.
Which of the following changes will increase the reaction rate?
an increase in the concentration of reactions increasing the surface area of the reactants
A reaction intermediate is a species corresponding to a local energy maximum on a reaction energy diagram.
false
Sulfuryl chloride, SO2Cl2(g), decomposes at high temperature to form SO2(g) and Cl2(g). The rate constant at a certain temperature is 4.68 × 10-5s-1. What is the order of the reaction?
first
If a system at equilibrium is disturbed by changing the concentration of a reactant or product, the equilibrium _____ will shift but the ratio of product to reactant will be ______ once the system reestablishes equilibrium. The value of K will be _______.
position, the same, unchanged
what would be predicted for the overall rate law from the proposed mechanism shown?
rate = k[(CH3)3C-Br] slowest
In an exothermic reaction,
the forward reaction will have a lower activation energy than the reverse reaction.
If the temperature is increased for a system at equilibrium, an exothermic reaction (H<0) will shift toward the ____ and the value of K will ___. On the other hand an endothermic reaction will shift toward the ____ and the value of K will _____
reactants, decrease; products, increase
Characteristics of Polyprotic acids
- A polyprotic acid has more than one ionizable proton- Polyprotic acids are generally weak acids - In caculations involving polyprotic acids we usually only take into account the H3O+ formed from the first dissociation
The strength of a weak base is indicated by its ______ - ionization constant Kb. The greater the value kb the _____ the base
base; stronger
An equilibrium calculation can be simplified by taking square roots on both sides of the equation when _
both numerator and denominator in the expression for K are perfect squares
a ______ is a substance that increases the rate of a reaction without being consumed. This type of substance is often used up and regenerated during the reaction.
catalyst
Which of the following has an effect on the magnitude of the equilibrium constant?
change in temperature
in order to determine reaction orders experimentally, a series of experiments are run in which one reactant concentration ____ while the other is kept ____
changes; constant
which of the following statements correctly describe chemical kinetics?
chemical kinnetics describe the chemical using collision theory Chemical kinetics is the study of reaction rates chemical kinnetics measures how fast reactants are converted into products
For a given reaction, Kc is the equilibrium constant based on the molar _____ of reactants and products while Kp is the equilibrium constant based on the partial _____ of reactants and products.
concentration pressures
The subscript "c" used in the symbols Qc and Kc indicate that these quantities are based on the ______________ of products and reactants.
concentrations
During the course of a reaction, reactant concentrations _____ and product concentrations _____.
decrease, increase.
the rate of reaction ___ over time bc as the reactant is used up there are ___ reactant particles to collide
decrease; fewer
reaction intermediates?
do not appear in the overall equation for the reaction formed and used up all over the reaction
The reaction X → Y is first-order overall and first-order with respect to the reactant X. The result of doubling the initial concentration of X will be to
double the initial rate
f the temperature of a system at equilibrium is increase the system will shift to use up the excess heat, favoring the _____ reaction. A decrease in temperature causes more heat to be produced, favoring the _____ reaction.
endothermic, exothermic
Small K intermediate K large K
equilibrium favors the reactants: there will be more reactants than products at equilibrium both reactants and products will be present in significant amounts at equilibrium equilibrium favors the products: more products than reactants
In a closed system a reversible chemical reaction will reach a state of dynamic chemical ______ when the rate of the forward reaction is ______ to the rate of the reverse reaction
equilibrium, equal
If an equilibrium system contains gaseous reactants and/or products, a change in volume will cause a change in concentration and pressure. A decrease in volume will cause the system to shift in the direction that produces ____ moles of gas in total, whereas an increase in volume causes a shift in the direction that produces ____ moles of gas in total
fewer; more
When the reaction A → B + C is studied, a plot of ln[A]t vs. time gives a straight line with a negative slope. What is the order of the reaction?
first
Raising the temperature of a reaction increases the rate of the reaction by increasing the___ and ___ of the collisions
frequency; energy
actors that affect the relative strength of oxoacids
- the electronegativity of the central nonmetal atom -the number of O atoms attached to the central nonmetal atom
Consider the general reaction 5Br-(aq) + BrO3-(aq) + 6H+(aq) → 3Br2(aq) + 3H2O(aq)For this reaction, the rate when expressed as Δ[Br2]/Δt is the same as
-0.6Δ[Br-]/Δt
Consider the following reaction8A(g) + 5B(g) → 8C(g) + 6D(g)If [C] is increasing at the rate of 4.0 mol L-1s-1, at what rate is [B] changing?
-2.5 mol L-1s-1
Consider the reaction 2NH3(g) → N2(g) + 3H2(g)If the rate Δ[H2]/Δt is 0.030 mol L-1s-1, then Δ[NH3 ]/Δt is
.−0.020 mol L¯1 s¯1
A 0.15 M solution of chloroacetic acid has a pH of 1.86. What is the value of Ka for this acid?
0.0014
Butadiene, C4H6 (used to make synthetic rubber and latex paints) reacts to C8H12 with a rate law of rate = 0.014 L/(mol·s) [C4H6]2. What will be the concentration of C4H6 after 3.0 hours if the initial concentration is 0.025 M?
0.0052 M
What is the pH of a 0.20 M HCl solution?
0.70
2NOBr(g) → 2NO(g) + Br2(g) Rate Constant?
0.800 L mol-1s-1
A reactant R is being consumed in a first-order reaction. What fraction of the initial R is consumed in 4.0 half-lives?
0.94
place the steps necessary to study the kinetics of a reaction order in the correct order
1. gather experimental data consisting of a series of plots of concentration vs time 2. determine the initial rates from the data 3. determine the reaction orders by comparing rates when concentrations change 4. deduce the actual rate law 5. calculate k, the rate constant
If the value of K for the forward reaction is less than 1, the value of K for the reverse reaction is ______ than 1.
greater
Which of the following reactants and/or products would not appear in the expression for Q or K for the following reaction?4HCl + MnO2 <-> MnCl2 + 2H2O +Cl2
h20 MnO2
The _____-_____ of a reaction is the time required for the reactant concentration to reach half its initial value.
half- life
A _____ catalyst exists in solution with the reaction mixture. must be a gas, liquid or soluble solid
homogeneous
All strong acids and bases appear strong in H₂O. This is because in water the stron₂gest acid possible is
hydronium, while the strongest base possible is hydroxide. In both cases the equilibrium favors the dissociation products, and water is said to exert a leveling effect on any strong acid or base.
The auto ionization of water is a process where water ionizes very slightly to form _____ ions and ______ ions
hydronium; hydroxide
Which of the following options are correctly interpret the rate law=k[H2][NO]^2? Select all that apply.
if [NO] is doubled while [H2] remains the same, the reaction will occur 4 times faster. The reaction is second order with respect to [NO]
As a reaction proceeds, the value of Q
increasing
which of the following changes would cause an increase in reaction rate
increasing the surface area of reactants increasing the concentration of reactants
The law of mass action reflects the observation that an equilibrium state is reached by a chemical system regardless of the ______ concentrations of reacting substances. In other words a chemical system can reach equilibrium either from the reactant or from the _____
initial, products
A reaction ______ is a species that is formed and then used up during the course of a reaction
intermediate
consider the equilibrium system c2h4 (g) + h2o (g)... -47.8 kJ What will be observed if the temp of the system increased
kc will decrease equilibrium will shift toward the reactants
a sample of a solid c is placed in a sealed reaction vessel containing 2.0 atm H2
kp= 0.39/(2.0x0.78)^2 = 0.26
since pK= -logK, a low pK value corresponds to a ___
large; large; low
A reaction is first-order with respect to the reactant R. Which of the following plots will produce a straight line?
ln[R] vs. time
If a reaction has a relatively ____ value of K and fairly ____ initial concentrations, equilibrium calculations can be simplified by assuming that the change in concentration (x) is _____ compared to (reactant)init. The assumption is justified as long as x is less than ___% of the initial concentration
low, high, small, 5
the higher the pH value, the ___ the hydronium and the ___ acidic the solution will be
lower; less
Catalyst
lowers the activation energy provides a different mechanism for the reaction
reactant concentration decreases ____quickly in a reaction with a higher rate than a reaction with lower rate
more
collision frequency provides and upper limit on how fast a reaction can take place
product; sum
catalyst increases the rate of a reaction by
providing an alternative reaction mechanism that has a lower activation energy
do not appear in a reaction quotient expression for a heterogenous reaction
pure solids pure liquids
Which of the following aqueous systems has the highest pH?
pure water
Chemical studies the ___ of chemical reactions. ie how fast reactants are converted into products
rate
or any mechanisms, only _______ involved up to and including the ____ step appear in the overall rate law.
reactants; slow
Le Chatelier's Principle states that when a chemical system at equilibrium is disturbed, the system will undergo a net reaction that ____ the effect of the disturbance and will attain a new ___ position.
reduces; equilibrium
A salt consisting of the anion of a ___ acid and the cation of a ___ base yields a
strong; weak
what is the molecualrity of the elementary step
termolecular
What are valid assumptions used in solving weak-acid equilibria problems?
the [H₃O⁺] from water is negligible [HA] at equilibrium is aproximately equal to [HA]intial
The reaction quotient for a gas phase reaction has a value of 2000. If the number of moles of reactants in the reaction equation is equal to that of the products, which of the following statements is definitely true?
the concentration of the products are generally larger than the concentration o the reaction
pure solids and liquids are not included in the reaction quotient or the equilibrium constant expression for a given heterogenous reaction
the concentrations of pure solids and liquids do not change as the reaction approaches equilibrium
When a chemical system is at equilibrium,
the concentrations of the reactants and products have reached constant values.
Transition Theory focuses on?
the high energy species that exists at the moment of an effective collision
0.45 mol PCl5 (g) is placed in a sealed 2.0-L
the initial PCl5 = 0.23 M at equilibrium pcl3 = 0.10 M Kc= (0.10)(0.10)/(0.13)
average rate and initial rate?
the initial rate is instantaneous rate at t=0 the average rate is an average of the instantaneous rates for a given period of time
which of the following factors are affected by an increase in reactant concentration?
the number of reactant collisions the number of reactant particles in a given volume the rate of reaction
the frequency factor, A
the product of the collision frequency Z and an orientation probability factor, p, which is specific for each reaction and related to the structural complexity of the colliding particles.
A solution is prepared by adding 0.10 mol of sodium fluoride, NaF, to 1.00 L of water. Which statement about the solution is correct?
the solution is neutral
What is the value f the structural orientation factor (p) based on?
the structural complexity of the reacting species.
Given: H2O(aq) + H2O(l) H3O+(aq) + OH-(aq) ΔH°rxn > 0 When the temperature of a sample of pure water is raised above 25°C,
the value of Kw will increase.
Reaction intermediates differ from activated complexes in that
they are molecules with normal bonds rather than partial bonds and can occasionally be isolated.
HCN has a Ka value of 6.3 x 10^-10 while acetic acid has a Ka
weaker; higher
N2O4 (g) If [N2O4] at the start of the reaction = 2.0 M
x =2.8% kc = 6.1 x10^-3 if the change in NO2 = +2x N2O4= (2.0-x)
reaction orders may be
zero, positive or negative integers, or fractions
A rate constant obeys the Arrhenius equation, the factor A being 2.2 ×1013 s-1 and the activation energy being 150. kJ mol-1. What is the value of the rate constant at 227°C, in s-1?
4.7 × 10-3 s-1
The decomposition of hydrogen peroxide is a first-order process with a rate constant of 1.06 × 10-3 min-1. How long will it take for the concentration of H2O2 to drop from 0.0200 M to 0.0120 M?
481 min
An equilibrium is established in which both the forward (fwd) and the reverse (rev) reactions are elementary. If the equilibrium constant Kc = 1.6 × 10-2 and the rate constant kfwd = 8.0 × 10-7 s-1 what is the value of krev?
5.0 x 10^-5 s-1
Determine the rate constant for the reaction 4A(g)+3B(g) yield 2C(g)
5.00x 10^3 L^2/mol^2xmin
The rate law for the rearrangement of CH3NC to CH3CN at 800 K is Rate = (1300 s-1)[CH3NC]. What is the half-life for this reaction?
5.3 × 10^-4 s
A Bronsted-Lowry base is a proton _____. A Bronsted-Lowry base must contain an available ____ pair of ________ in its formula in order to form a(n) _______ bond to the H+.
Acceptor, lone, electrons, covalent
The hydrated Al3+ ion, Al(H2O)63+, is a weak acid in water. What are the products of its reaction with H2O? Al(H2O)6^3+(aq) + H2O(l) → ?
Al(H2O)5OH2+(aq) + H3O+(aq
The hydrated Al3+ ion, Al(H2O)63+, is a weak acid in water. What are the products of its reaction with H2O? Al(H2O)63+(aq) + H2O(l) → ?
Al(H2O)5OH^2+(aq) + H3O+(aq)
All other factors being equal, which of the following mixtures will have the fastest reaction rate?
An aqueous reactant mixed with another aqueous reactant with a stirring device. [The surface area of the reactants is maximized for this situation. The reactants are mixed and in the same phase]
Which of the following conditions must be satisfied for a collision between reactants to be effective?
Appropriate molecular orientation. Enough energy to overcome Ea.
Which of the following is considered a Lewis acid?
BCl3
Which of the following statements correctly describes a system at equilibrium for which K=1.2
Both products and reactants are present in significant amounts at equilibrium
If a system is disturbed by a change in concentration, the system will shift to ___ a substance that is added and to ___ a substance that has been removed
Consume; produce
There is/are three main factor(s) that can affect the rate of a chemical reaction. One factor is the concentration of molecules. The reaction rate is directly proportional to the number of molecular collisions that can occur, which depends on the concentration of the reactants. The physical state of the reactants will also have an effect on the rate of the reaction. The reactants must mix for the reaction to occur. Finally the temperature has an effect on the rate of reaction. This is due to the fact that at a higher temperature the molecules have a higher kinetic energy and higher rate of collisions. Thus more molecules will react per unit time.
Factors of rate of reaction
Which of the following is NOT a conjugate acid-base pair?
H2PO4-/PO4
Which of the following 0.1 M salt solutions will be basic?
NaCN CN- is the conjugate base of a weak acid; Na+ will not react
The equilibrium constant, Kp, for the reaction CO(g) + H2O(g) CO2(g) + H2(g) at 986°C is 0.63. A rigid cylinder at that temperature contains 1.2 atm of carbon monoxide, 0.20 atm of water vapor, 0.30 atm of carbon dioxide, and 0.27 atm of hydrogen. Is the system at equilibrium?
No, the forward reaction must proceed to establish equilibrium.
The equilibrium constant, Kp, for the reaction H2(g) + I2(g) 2HI(g) is 55.2 at 425°C. A rigid cylinder at that temperature contains 0.127 atm of hydrogen, 0.134 atm of iodine, and 1.055 atm of hydrogen iodide. Is the system at equilibrium?
No, the reverse reaction must proceed to establish equilibrium
The equilibrium constant, Kp, for the reaction H2(g) + I2(g) 2HI(g) is 55.2 at 425°C. A rigid cylinder at that temperature contains 0.127 atm of hydrogen, 0.134 atm of iodine, and 1.055 atm of hydrogen iodide. Is the system at equilibrium?
No, the reverse reaction must proceed to establish equilibrium.
Which of the following options correctly describe a solution with a pH = 8.00? Select all that apply
(1) - [OH-] > [H3O+] (2) - The solution is basic.
About half of the sodium carbonate produced is used in making glass products because it lowers the melting point of sand, the major component of glass. When sodium carbonate is added to water it hydrolyses according to the following reactions. CO32-(aq) + H2O(l) HCO3-(aq) + OH-(aq) K1 HCO3(aq) + H2O(l) H2CO3(aq) + OH-(aq) K2These can be combined to yield CO32-(aq) + 2H2O(l) H2CO3(aq) + 2OH-(aq) K3What is the value of K3?
(k1)(k2)
A student adds 0.1 mol of oxalic acid and 0.1 mol of sodium dihydrogen phosphate to enough water to make 1.0 L of solution. The following equilibrium is established with the concentrations of the products greater than the concentrations of the reactants. Which of the statements about the equilibrium system is correct? H2C2O4(aq) + H2PO4(aq) HC2O4(aq) + H3PO4(aq)
Phosphoric acid is a weaker acid than oxalic acid.
Ammonium cyanate (NH4CNO) reacts to form urea (NH2CONH2). At 65°C the rate constant, k, is 3.60 L mol-1s-1. What is the rate law for this reaction?
Rate = 3.60 L mol-1s-1[NH4CNO]2
For the reaction 3A(g) + 2B(g) → 2C(g) + 2D(g)the following data were collected at constant temperature. Determine the correct rate law for this reaction.
Rate = k[A]^2[B]
Consider the following mechanism for the oxidation of bromide ions by hydrogen peroxide in aqueous acid solution. H+ + H2O2 H2O+-OH (rapid equilibrium)H2O+-OH + Br- → HOBr + H2O (slow)HOBr + H+ + Br- → Br2 + H2O (fast)Which of the following rate laws is consistent with the mechanism?
Rate = k[H2O2][H+][Br-]
Which of the following changes will cause the equilibrium shown to shift toward the products? Select all that apply.Fe3O4 +4H2 <-> 3Fe +4H2O
Remove H2O from the reaction vessel. Add H2 without changing the volume.
Acid ionization is represented by the general equation HA ⁺ H₂O (l) ⇌ H₃O⁺ (aq) ⁺ A⁻ (aq)For a strong acid the equilibrium lies far to the _____ and [H₃O⁺] is much _____ than [HA]. For a weak acid, the equilibrium lies far to the ______ and [H₃O⁺] is much _____ than [HA].
Right, higher ; Left, lower
Which of the following statements correctly describe the kinetics of an elementary step? Select all that apply.
The elementary step 2HI (g) --> H2 (g) + I2 (g) follows second order kinetics. the rate law for an elementary step can be deduced from its balance equation. For an elementary step, reaction order equals molecularity.
The rate law cannot be predicted from the stoichiometry of a reaction.
True
Which questions can be answered from an integrated rate law that can not be answered by other forms of the rate law?
- how long it will it take to use up X moles per liter of A?-What is [A] after y minutes of the reaction
n water, the following equilibrium exists: H+(aq) + OH-(aq) H2O(l) In pure water at 25°C, the concentration of H+ ions is 1.00 × 10-7 mol/L. Calculate the value of the equilibrium constant for the reaction as written above.
1.00 × 10^-14
The following reaction, in CCl4 solvent, has been studied at 25°C. 2BrCl Br2 + Cl2 The equilibrium constant Kc is known to be 0.141. If the initial concentration of chlorine is 0.0300 M and of bromine monochloride is 0.0200 M, what is the equilibrium concentration of bromine?
1.35 x 10^-3
The equilibrium constant, Kp, has a value of 6.5 × 10-4 at 308 K for the reaction of nitrogen monoxide with chlorine. 2NO(g) + Cl2(g) 2NOCl(g)What is the value of Kc?
1.6 x 10^-2
Phosphoric acid, H3PO4, is a triprotic acid, for which Ka1 = 7.2 × 10-3, Ka2 = 6.3 × 10-8 and Ka3 = 4.2 × 10-13. What is the value of Kb for the hydrogen phosphate anion, HPO4?
1.6 × 10-7
Nitrogen dioxide decomposes according to the reaction 2NO2(g) 2NO(g) + O2(g)where Kp = 4.48 × 10-13 at 25°C. What is the value for Kc?
1.83 x 10^-14
What is the [OH-] for a solution at 25°C that has pH = 4.29?
1.9 × 10^-10 M
A reaction is second-order with respect to the reactant R. Which of the following plots will produce a straight line?
1/[R] vs. time
What is the pH of a 0.0035 M KOH solution?
11.54
What is the pH of a 0.0125 M NaOH solution?
12.097
What is the pH of 0.0165 M NaOH? Is the solution neutral, acidic, or basic? The pH is:
12.2 basic
What is the pH of a 0.050 M LiOH solution?
12.70
Nitric oxide and bromine were allowed to react in a sealed container. When equilibrium was reachedPNO = 0.526 atm, = 1.59 atm, and PNOBr = 7.68 atm. Calculate Kp for the reaction. 2NO(g) + Br2(g) 2NOBr(g)
134
nitrous acid hno2 has a ka of 7.1
2.1x10^-2
What is the pH of a 6.26 × 10−3 M HI solution?
2.2 acidic
Calculate the Ka value for the anilium ion (C6H5NH3+) if Kb for aniline (C5H5NH2) is 4.0 x 10^-10
2.5 x 10^-5Ka = (1 x 10^-14)/Kb = (1 x 10^-14)/(4 x 10^-10) = 2.5 x 10^-5
What is the pH of a 0.00200 M HClO4 solution?
2.69
The equilibrium constant, Kc, for the decomposition of COBr2 COBr2(g) CO(g) + Br2(g)is 0.190. What is Kc for the following reaction? 2CO(g) + 2Br2(g) 2COBr2(g)
27.7
At 25C, hydrogen iodide breaks down very slowly to hydrogenand iodine: rate=k[HI]2 The rate constant at this temperature is 2.4 x10-21 L/mol*s. If 0.0100 mol of HI(g) is placed in a 1.0-L containier, howlong will it take for 10.0% of the HI to react?
4.26962963*10^21 seconds
What is the [H3O+] for a solution at 25°C that has pOH = 5.640?
4.37 × 10^-9 M
Consider the following two equilibria and their respective equilibrium constants: (1) NO(g) + ½O2(g) NO2(g)(2) 2NO2(g) 2NO(g) + O2(g)Which one of the following is the correct relationship between the equilibrium constants K1 and K2?
K2 = (1/K1)^2
Consider the equilibrium reaction: N2O4(g) 2NO2(g) Which of the following correctly describes the relationship between Kc and Kp for the reaction?
Kp = RT × Kc
Which of the following statements correctly explains why it is reasonable to assume that for a weak acid [HA] at equilibrium is approximately equal to [HA]init under most circumstances?
Most molecules of the weak acid remain undissociated at equilibrium
What do the dashed lines represent in the illustration of the transition state of a reaction between BrCh3 and OH-?
The partial bonds forming and breaking in the reactants
The acid dissociation constant Ka equals 1.26 × 10-2 for HSO4- and is 5.6 × 10-10 for NH4. Which statement about the following equilibrium is correct? HSO4-(aq) + NH3(aq) SO42-(aq) + NH4+(aq)
The products will be favored because the hydrogen sulfate ion is a stronger acid than the ammonium ion.
The kinetics of the decomposition of dinitrogen pentaoxide is studied at 50°C and at 75°C. Which of the following statements concerning the studies is correct?
The rate at 75°C will be greater than the rate at 50°C because the number of molecules with enough energy to react increases with increasing temperature.
If the activation energy of a reaction decreases by 10.0 kJ/mol, from 100.0 to 90.0 kJ/mol, what effect will this have on the rate of reaction at 298K?
The rate will increase, by a factor of more than 50.
Which of the following options correctly describe the effect on increasing temperature?
The reaction rate increases. Particles collide more frequently Particles collide more energetically
Carbon monoxide and chlorine combine in an equilibrium reaction to produce the highly toxic product, phosgene (COCl2) CO(g) + Cl2(g) COCl2(g) If the equilibrium constant for this reaction is Kc = 248, predict, if possible, what will happen when the reactants and product are combined with the concentrations shown. [CO] = [Cl2] = 0.010 M; [COCl2] = 0.070 M
The reaction will proceed to the left.
A solution is prepared by adding 0.10 mol of potassium chloride, KCl, to 1.00 L of water. Which statement about the solution is correct?
The solution is neutral.
The substance HCl is considered
a strong Arrhenius acid.
The _____ energy of a reaction is the energy threshold that colliding molecules must exceed in order to react.
activation
will change the pressure in a reaction involving only gases at equilibrium?
adding an inert gas changing the volume of the container adding or removing a reactant or product
the product of a Lewis acid-base reaction is called an
adduct, which is a single species containing a new covalent bond
