Chemical kinetics Questions and Answers

Given the reaction: HF (aq) =Ht H* (aq) + F (aq) increasing the pressure will: a) cause the system to shift to the right Ob) raise the temperature of the system Oc) have no effect on the equilibrium Od) cause the system to shift to the left

If the initial cyclopropane concetration is 0.0560 M, what is the cyclopropane concentration after 237 minutes?

The activation energy, Ea, for a particular reaction is 37.8 kJ/mol. If the rate constant at 280 K is 0.178 M/s, then what is the value of the rate constant at 381 K? (R = 8.314 J/mol K)

What is the rate at which Br(aq) disappears in the reaction below if the rate of disappearance of BrO, (aq) is 0.022 M/s? BrO3- + 5 Br- + 6 H+ → 3 Br₂ + 3H₂O

The reaction: 2NO(g) + 2H₂ (g) N₂ (g) + 2H₂O (g) Was studied at 904 °C, and the data in the table were collected. a) Write the general rate equation for this reaction. b) Solve for the exponents. c) Solve for the rate constant. d) What is the initial rate when [NO]=0.350 M and [H₂] = 0.205 M?

Write the equilibrium-constant expressions and obtain numerical values for each constant in a. the basic dissociation of aniline, C6H5NH₂ (Ka = 2.51 x 10-5). b. the acidic dissociation of hydrocyanic acid, HCN (Ka = 6.2 x 10-¹0).

Which one of the following changes could double the rate of the reaction 2 A(g) + B(g) + 3 C(g) → 3 D(g) + E(g) with the rate law Rate = K[A][B]²? A) double [A] B) double [B] C) double [C] D) cut [A] in half

The temperature dependence of the reaction rate constant is given by the equation: Ink = In A-Ea/RT Where: k = rate constant T = temperature A = frequency factor Ea Energy of activation Use the References to access important values if needed for this question. Use the rules for logarithms and exponents to solve for k. NOTE: Write Ea as Ea for the answers below. Use^ (caret) to enter superscripts.

The activation energy, Ea, for a particular reaction is 13.6 kJ/mol. If the rate constant at 475 K is 0.0450 1/min, then what is the value of the rate constant at 701 K? (R = 8.314 J/mol • K)

The rate of the reaction represented above increases significantly in the presence of Pd(s). Which of the following best explains this observation? A Pd absorbs the heat produced in the reaction. B dissociates into additional reactant molecules, thereby increasing the reaction rate C One of the reactants binds on the surface of Pd, which introduces an alternative reaction pathway with a lower activation energy. D One of the products binds on the surface of Pd, which increases the reaction rate by decreasing the concentration of products in the mixture.

The gas NO reacts with H₂, forming N₂ and H₂O: 2NO(g) + 2H₂ (g) → 2H₂O (g) + N₂ (g) If A[NO]/At = -19.0 M/s under a given set of conditions, what are the rates of change of [N 2] and [H₂O]? Rate of change of [N₂]: Rate of change of [H₂O]: PRACTICE: Consider the following reaction: 2HBr (g) → H₂ (g) + Br2 (g) In the first 23.0 s of this reaction the of HBr dropped from 0.550 M to 0.457 M. Calculated the average rate (M.s-¹) of the reaction in this time interval. Express your answer using two significant figures. If the volume of the reaction in part (a) was 1.50 L. what amount of Br₂ (in moles) was formed during the 15.0 s of the reaction? Express your answer using two significant figures.

A certain reaction is second order in N₂ and second order in H₂. Use this information to complete the table below. Be sure each of your answer entries has the correct number of significant digits.

At a certain temperature this reaction follows first-order kinetics with a rate constant of 0.0041 s¹: 2NH3(g) → N₂(g) + 3H₂(g) Suppose a vessel contains NH3 at a concentration of 0.910 M. Calculate how long it takes for the concentration of NH3 to decrease to 6.0% of its initial value. You may assume no other reaction is important. Round your answer to 2 significant digits.

The Ksp for AgCl₂ is 1.26 10¹ M. If a solution is make by mixing 0.570 mL of 0.350 M Ag(NO3)2 and 0.220 mL of 0.330 M KCl, would precipitation occur? yes no more information is needed to determine this

For the following reaction A + 2B + 2C → A+ B₂C₂ the observed rate law is Rate = k[A][B]2[C]1 What is the reaction order with respect to A? to C ? What is overall order? with respect to B?

What is the concentration of A after 50.7 minutes for the second order reaction A→ Products when the initial concentration of A is 0.250 M? (k = 0.117 M-¹min-¹)

0.01 moles of sulphuryl chloride SO₂Cl₂(g) is taken in a sealed tube & heated to 400 K. It decomposes following 1st order kinetics according to reaction: SO₂Cl₂(g) → SO₂(g) + Cl₂(g) The tube is broken after 4 hours & gas passed through a 25 ml of an acidified 1 N iodine solution where all SO₂ is oxidised to SO2-. The resulting solution required 10 ml of 1 M Hypo solution. What is half life in hours.

How would each of the following affect the rate of the reaction? Increasing concentration: Decreasing the surface area: Adding a catalyst: Decreasing the size of particle:

Consider the reaction: 5A+3B 2C The rate of the reaction is found to be 0.0493 M/s. What is the rate of change of B? Be sure to consider whether the substance is disappearing or appearing in your answer.

A zero-order reaction has a constant rate of 1.40x10-4 M/s. If after 55.0 seconds the concentration has dropped to 8.50x10-2 M, what was the initial concentration?

The closeness of particles of gas and their low speeds allow intermolecular forces to become important at certain pressures and temperatures. Which best describes this statement? This is a limitation of the kinetic-molecular theory. This is a postulate of the kinetic-molecular theory. This describes ideal gas behavior using the kinetic-molecular theory. This describes ideal gas behavior without the kinetic-molecular theory.

Classify the molecules based on whether the molecule has a standard enthalpy of formation, ΔHf equal to 0. Assume all conditions are at standard pressure and temperature (STP).

A first-order reaction A B has the rate constant k = 2.8x10-3-1 If the initial concentration of A is 1.8x10-2 M, what is the rate of the reaction at t= 660 s? Express your answer to two significant figures and include the appropriate units.

For the following three questions, consider the following reaction mechanism: Step 1 2F + A -> Z + 2J fast Step 2 Z+JZ+M+ P slow Step 3 P + J-2Z + A fast The intermediates in this reaction are J and P P and Z F and M A and Z J and M

The rate of popcorn popping at different temperatures was found to be described by the Arrhenius equation. How many times faster does the popcorn pop at 210.°C compared to 180.°C when the activation energy is 167 kJ/mol? 15.7 8.38 x 106 8.80 x 106 1.20 42.6

The reaction A(g) + 2B(g) → C(g) is an elementary reaction. In an experiment involving this reaction the initial partial pressures of A and B are PA = 0.40 atm and PB = 1.0 atm respectively. When PC = 0.3 atm, the rate of the reaction relative to the initial rate is x. Find value of 100x.

Which of the following factors does NOT affects the rate of a chemical reaction? All of these affect the reaction rate Temperature Reactant color Addition of Catalyst Concentration of reactants

Select all of the true statements from the following. Step 1: Cl₂ + Z→ 2 Cl (slow) Step 2: Cl + CHCl3 → HC1+CCl3 (fast) Step 3: CI+CCl3 → CCl4 + Z (fast) The overall reaction for the mechanism shown above is Cl₂ + CHCl3 → HCI+ CI+ CCl4. If a reaction is second order with respect to (X) and first order with respect to (Y), then its rate expression would be rate = k (X)(Y)². Cl is an intermediate in the mechanism shown above. Z is a catalyst in the mechanism in the mechanism shown above.

The half life for the radioactive decay of carbon-14 to nitrogen-14 is 5.73 × 10³ years. Suppose nuclear chemical analysis shows that there is 0.470 mmol of nitrogen-14 for every 1.000 mmol of carbon-14 in a certain sample of rock. Calculate the age of the rock. Round your answer to 2 significant digits.

The mechanism of a reaction is shown below. HOOH+I- → HOI+OH- (slow) HOI+I- → I₂ + OH- (fast) 2OH- + 2H₂O+ → 4 H₂O (fast) A. What is the overall reaction? B. Which compounds are intermediates? C. Predict the rate law based on this mechanism. D. What is the overall order of the reaction?

For the reaction A + B → C, the rate constant at 80 °C is 3.0 x 10-2 and the rate constant at 120° C is 1.2 x 10-1. A. What is the activation energy in kJ/mol? B. What is the rate constant at 100° C.

A blood sample is assayed for creatine kinase activity. It is found that after 5 minutes of reaction, 16.8 µmol of creatine phosphate (the product of the reaction) is produced. How many international units of creatine kinase are present in the sample?

Chemical reactions occur when molecules or atoms collide in a way that the bonds between atoms break and new bonds form. Breaking the bonds of the reactants requires energy, whereas bond formation releases energy. Select the true statements regarding energy changes during a reaction. The activation energy, Ea, of the forward reaction is the difference between the energy of the products and the energy of the transition state. If the heat of reaction, AH, is positive, the energy of the products is lower than the energy of the reactants and the reaction is exothermic. Increasing the concentration of reactants increases the number of collisions, and the reaction goes faster. Decreasing the temperature decreases the kinetic energy of the reactants, and the reaction goes more slowly. Reactants must collide with proper orientation and with energy greater than or equal to the activation energy for a reaction to occur. When the activation energy is high, the reaction rate is fast. The energy of a collision between atoms or molecules must be greater than or equal to the activation energy, Ea, for bonds to be broken.

For the reaction 2 SO3 +2 SO₂ + O₂ calculate the average rate, A[SOV/At, between 10.0 min and 40.0 min for the loss of SO3. A 1.2x10-4 M/min B. 1.8x10-3 M/min C. 5.1x10-3 M/min D. 1.4x10-3 M/min E. 3.1x10-3 M/min

Which is an incorrect statement when discussing molecular collisions leading to the chemical reaction, AB+ CD-AD+ CB? The slower the motion of the molecules, the more likely that this reaction will become an equilibrium reaction favoring the left side of the equation. The relationship between molecular collisions and reaction rate is direct. The faster the motion of the molecules, the greater the probability that a chemical reaction will occur. The faster the motion of the molecules, the more likely they are to collide.

In the provided reaction profile, the black line represents the pathway of the reaction of A and B going to AB. The red line represents the pathway when catalyst K is added. What is catalyst K doing in the reaction? A) Lowering the enthalpy of the reaction B) Lowering the activation energy of the reaction C) Changing the mechanism of the reaction D) Both A and B E) Both B and C