Chem 1 Flashcards

A student ran the following reaction in the laboratory at 450 K:

PCl₅(g) PCl₃(g) + Cl₂(g)

When she introduced 1.07 moles of PCl₅(g) into a 1.00 liter container, she found the equilibrium concentration of Cl₂(g) to be 3.65E-2 M.

Calculate the equilibrium constant, K_c, she obtained for this reaction

The following initial rate data are for the reaction of nitrogen dioxide with fluorine:

2 NO₂ + F₂ 2 NO₂F

Complete the rate law for this reaction in the box below.
Use the form k[A]^m[B]ⁿ , where '1' is understood for m or n and concentrations taken to the zero power do not appear. Don't enter 1 for m or n

A reaction profile (not to scale!) for the reaction

C₂H₄ + HCl

C₂H₅Cl is shown below:

Which of the following are true?
Choose all that apply.
a. If the energy of the activated complex were increased, E_a would increase.

b. The value of E_a at higher temperatures would be lower than 205 kJ.

c.The energy of the products is lower than the energy of the reactants.

d.The reaction is exothermic.

Consider the following system at equilibrium where H^o = -16.1 kJ, and K_c = 154, at 298 K:

2 NO(g) + Br₂(g) 2 NOBr(g)

If the VOLUME of the equilibrium system is suddenly increased at constant temperature:

The value of K_c C

A. Increases.B. Decreases.C. Remains the same.
The value of Q

A. Is greater than K.B. Is equal to K.C. Is less than K.

The reaction must

A. Run in the forward direction to restablish equilibrium.B. Run in the reverse direction to restablish equilibrium.C. Remain the same. Already at equilibrium.
The number of moles of Br₂ will

A. Increase.B. Decrease.C. Remain the same.

The gas phase reaction between hydrogen and iodine is proposed to occur as follows:

.....step 1..... fast:...... I₂ 2 I

.....step 2..... slow:.... H₂ + 2 I 2 HI

(1) What is the equation for the overall reaction? Use the smallest integer coefficients possible. If a box is not needed, leave it blank.

(2) Enter the formula of any species that acts as a reaction intermediate? If none leave box blank:

(3) Complete the rate law for the overall reaction that is consistent with this mechanism.
Use the form k[A]^m[B]ⁿ... , where '1' is understood (so don't write it if it's a '1') for m, n etc.

Hydrogen peroxide decomposes into water and oxygen in a first-order process.
H₂O₂(aq) → H₂O() + 1/2 O₂(g)
At 20.0 °C, the half-life for the reaction is 3.92E+4 seconds. If the initial concentration of hydrogen peroxide is 0.822 M, what is the concentration after 3.27 days?

The equilibrium constant, K_c, for the following reaction is 77.5 at 600 K.
CO(g) + Cl₂(g) COCl₂(g)
Assuming that you start with equal concentrations of CO and Cl₂ and no COCl₂ is initially present, describe the relative abundance of each species present at equilibrium.

[CO]
[COCl₂]
[Cl₂]
1) Higher 2) Lower 3) Can't tell

Consider the reaction:
C(s) + 1/2 O₂(g) CO(g)

Write the equilibrium constant for this reaction in terms of the equilibrium constants, K_a and K_b, for reactions a and b below:

a.) C(s) + O₂(g) CO₂(g).............K_a

b.) CO(g) + 1/2 O₂(g) CO₂(g).............K_b

For the reaction coordinate diagram shown below, what is the order of the reaction?

onsider the following system at equilibrium where K_c = 1.29E-2 and H^o = 108 kJ/mol at 600 K:
COCl₂(g) CO(g) + Cl₂(g)
The production of CO(g) is favored by
Indicate True (T) or False (F) for each of the following choices.
1. Increasing the temperature.
2 . Decreasing the pressure (by changing the volume).
3. Decreasing the volume.
4. Removing COCl₂.
5. Adding Cl₂.

For the reaction A → B, the rate law is
.
What are the units of the rate constant where time is measured in seconds?

The activation energy for the gas phase decomposition of t-butyl acetate is 170 kJ.

CH₃COOC(CH₃)₃ (CH₃)₂C=CH₂ + CH₃COOH
The rate constant at 539 K is 7.12E-4 /s. The rate constant will be 8.33E-3 /s at

The equilibrium constant, K_c, for the following reaction is 1.29E-2 at 600 K.
Calculate K_p for this reaction at this temperature.

COCl₂(g) CO(g) + Cl₂(g)

Which of the following statements is/are CORRECT?
1.A reaction will proceed in the forward direct when Q>K

2.A reaction favors the formation of products if K >> 1.

3.In an Endothermic reaction, increasing the temperature will increase [Reactants

For the decomposition of ammonia on a tungsten surface at 1100 ^oC

2 NH₃ -> N₂ + 3 H₂

the average rate of disappearance of NH₃ over the time period from t = 0 s to t = 1.63E+3 s is found to be 3.40E-6 M s ^-1.

What is the average rate of appearance of N₂ over the same time period?

Which of the following is true regarding the rate constant (k)?

1. It is temperature independent
2. It is concentration independent
3. It is a proportionality constant

Write the equilibrium constant expression, K, for the following reaction:
Please enter the compounds in the order given in the reaction.If either the numerator or denominator is 1, please enter 1.

BaSO₄(s) Ba²⁺(aq) + SO₄ ^2-(aq)

The equilibrium constant, K_c, for the following reaction is 55.6 at 698 K:

H₂(g) + I₂(g) 2 HI(g)

Calculate the equilibrium concentrations of reactants and product when 0.305 moles of H₂ and 0.305 moles of I₂ are introduced into a 1.00 L vessel at 698 K.

Consider the following reaction where K_p = 9.52E-2 at 350 K:

CH₄(g) + CCl₄(g) 2 CH₂Cl₂(g)

If the three gases are mixed in a rigid container at 350 K so that the partial pressure of each gas is initially one atm, what will happen?

Indicate True (T) or False (F) for each of the following:

1 . A reaction will occur in which CH₂Cl₂(g) is produced.
2. K_p will decrease.
3. A reaction will occur in which CH₄ is produced.
4. Q is greater than K.
5. The reaction is at equilibrium. No further reaction will occur.

or the gas phase decomposition of t-butyl acetate,

CH₃COOC(CH₃)₃ (CH₃)₂C=CH₂ + CH₃COOH
the rate constant has been determined at several temperatures. When ln k in s^-1 is plotted against the reciprocal of the Kelvin temperature, the resulting linear plot has a slope of -2.04E+4 K and a y-intercept of 30.7.

The activation energy for the gas phase decomposition of t-butyl acetate is

NaHCO₃ (aq) + HNO₃ (aq) NaNO₃(aq) + H₂O(l) + CO₂(g)

Which of the following could be a way to increase the rate of the reaction above?
Indicate "yes" or "no" for each choice.

Increasing the temperature.
Doubling the pressure.
Increasing the concentration of NaHCO₃
Increasing the concentration of HNO₃

The reaction of hypochlorite ion with iodide ion in 1 M aqueous hydroxide solution

OCl^- + I^- -> OI^- + Cl^-

is first order in OCl^- and first order in I^-.
Complete the rate law for this reaction in the box below.
Use the form k[A]^m[B]ⁿ... , where '1' is understood for m, n ...(don't enter 1) and concentrations taken to the zero power do not appear

Hydrogen peroxide decomposes into water and oxygen in a first-order process.
H₂O₂(aq) → H₂O() + 1/2 O₂(g)
At 20.0 °C, the half-life for the reaction is 3.92E+4 seconds. If the initial concentration of hydrogen peroxide is 0.696 M, what is the concentration after 7.15 days?

CO (g) + Br₂ (g) COBr₂(g)

Which of the following could be a way to increase the rate of the reaction indicated above?
Indicate "yes" or "no" for each choice.

Increasing the temperature.
Doubling the pressure.
Increasing the concentration of CO.
Increasing the concentration of Br₂.

In a study of the decomposition of nitrosyl bromide at 10 ^oC

NOBr NO + ½ Br₂

the concentration of NOBr was followed as a function of time.

It was found that a graph of 1/[NOBr] versus time in seconds gave a straight line with a slope of 1.22 M^-1s^-1 and a y-intercept of 2.60 M^-1.

Based on this plot, the reaction is ____ order in NOBr and the rate constant for the reaction is ____

For the second-order reaction below, the rate constant of the reaction is 8.88E-3 M^–1s^–1. How long (in seconds) is required to decrease the concentration of A from 1.34 M to 0.119 M?

2A → B rate = k [A]²

The equilibrium constant, K_p, for the following reaction is 0.497 at 500 K.
Calculate K_c for this reaction at this temperature.

PCl₅(g) PCl₃(g) + Cl₂(g)

The activation energy for the gas phase isomerization of dimethyl maleate is 111 kJ/mol.

cis-CH₃OOCCH=CHCOOCH₃ trans-CH₃OOCCH=CHCOOCH₃
The rate constant is 7.08E-4 s^-1 at 701 K. At what temperature is the rate constant 3.77E-3 s^-1?

For the gas phase decomposition of vinyl ethyl ether,

CH₂=CH-OC₂H₅ C₂H₄ + CH₃CHO
the rate constant has been determined at several temperatures. When ln k in s^-1 is plotted against the reciprocal of the Kelvin temperature, the resulting linear plot has a slope of -2.20E+4 K and a y-intercept of 26.3.

The activation energy for the gas phase decomposition of vinyl ethyl ether is

Consider the following reaction:

NH₄Cl (s) -> NH₃ (g) + HCl (g)

If a flask maintained at 554 K contains 0.125 moles of NH₄Cl(s) in equilibrium with 1.59E-2 M NH₃(g) and 2.73E-2 M HCl(g), what is the value of the equilbrium constant at 554 K?

What does decreasing volume do?

if Q > K

if Q < K