Answer questions in this section if your instructor has assigned the Classical K
ID: 694509 • Letter: A
Question
Answer questions in this section if your instructor has assigned the Classical Kinetics questions. K4. A reaction is found to have a half-life that is independent initial concentration. What is the overall order of the reaction? (A) 0 Which statement is NOT true for the behavior of a K1. Lasers are often used in kinetics experiments. Which energy level diagram does NOT represent a laser system? (B) 1 (C2(D) 3 KS. catalyst? (A) A catalyst speeds up the rate of a reaction (B) A catalyst reduces the activation energy for a reaction. (C) A catalyst increases the rates of both the forward and reverse reactions. (D) A catalyst increases the equilibrium constant and final product concentrations. K6. Under certain conditions, the metabolism of C,H,OH is zero-order, which plot results in linear behavior? A) IC H,OH] versus B) IC,H,OHI versus (C) [C,H,OH) versus(D) In [C,H,OH] versus K2. The reaction coordinate diagram E for the conversion of 1-butene to cis- and trans-2-butene on a MgSO surface at 350 K is shown. K7. If the temperature increased from 10 to 20 and the 1-butene cis-2-butene rate is found to double, then which property has also doubled? (A) Average energy (B) Average velocity (C) Number of molecular collisions per second (D) Number of molecular collisions that have at least Reaction Coordinate What is the relationship between the concentrations of the cis and trans isomers once equilibrium is reached? (A) [cis] [trans] (B) [cis] [trans (D) The final concentration depends on the total pressure energy, E K8. The decomposition of urea in 1 M HCI occurs according to the reaction NH,CONH, +2H,0 of the gases. From the data provided, the The vibrational frequency for gaseous carbon monoxide is 2170 cm. As CO chemisorbs on a metal surface, the vibrational frequency is expected to K3. activation energy is (A) -R multiplied by the slope of the line. (B) R multiplied by the slope of the line. (C) the negative of the slope of the line. (D) the slope of the line. (A) remain unchanged. (B) increase because the C-O bond gets stronger when it attaches to a metal surface. decrease because of the decreased electron density between the carbon atom and the oxygen atom. (C) increase because of the increased electron density between the carbon atom and the metal surface. (D)Explanation / Answer
K2- B
Reason: From the energy profile, the activation e.eegy for both the products is same (see the peak in the plot). So, the ratio of products formed will be completely governed by thermodynamics. Since E(trans) < E(cis) i.e. trans is more stable than cis, hence trans is formed more than cis.
K3-C
The under harmonic oscillator approximation, the bond can be imagined to be a spring with force constant k. Since frequency is proportional to k^1/2, k decreases as the bond weakens. Bond weakens because some of the electron density is shared with the metal surface, as written in the correct option.
K4- B
For a first order reaction the half life is given by the expression:
t(1/2) = ln(2)/k where k is the rate constant of the reaction.
Thi s expression doesn't contain any concentration term. This is derivable from the integrated rate equation for a first order reaction.
K5- D
Since all other options are perfectly true for a catalyst.
Also, kinetics have little to do with the equilibrium of a reaction.
K6-A
Let [C2H5OH] be denoted by C; and [C2H5OH] at time t=0 be C0.
The differential equation for rate for zero-order reaction is:
dC/dt = k
=> dC = kdt
Integrating both sides and putting limits for 'C' to be C0 to C and for 't' to be from 0 to t, we get:
C - C0 = kt
=> C = kt + C0
Hence a linear equation it is.