CHM 2046 exam 2
acidic basic neutral
1-6 > 7 7
Sodium hydroxide is classified a strong base in water. This means that it
100% of the maximum number of possible hydroxide ions
In regard to the Arrhenius equation which of the following is NOT correct?
A is the frequency factor, how often a collision occurs with the correct orientation Ea/ e^-Ea/RT is the activation energy, barrier height and the fraction of the molecules with enough e to cross the barrier T is temperature in kelvins R is the gas law constant known as 8.314 J K-1mol-1.
The same number of moles of acetic acid and hydrogen chloride are placed in beakers containing water. After this addition, the beaker with the HCl has more hydronium ions than the beaker with added acetic acid. HCl is classified as_________
A stronger acid than acetic acid.
Write a balanced reaction for which the following rate relationships are true? Rate = -1/2 Δ[N2O5 ]/ Δt = 1/4 Δ[NO 2]/ Δt = Δ[O 2]/ Δt A) 2 N2O5 → 4 NO2 + O2 B) 4 NO2 + O2 → 2 N2O5 C) 2 N2O5 → NO2 + 4 O2 D) 1/4 NO2 + O2 → 1/2 N2O5 E) 1/2 N2O5 → 1/4 NO2 + O2
A) 2N2O5 --> 4NO2 + O2
Weak base
Ammonia Methyl amine pyridine water
The combustion of ethylene proceeds by the reaction C2H4 (g) + 3O2 (g) → 2CO2 (g) + 2H2O (g) When the rate of disappearance of O2 is 0.47 M s-1, the rate of appearance of CO2 is __________ M s-1. a.) 0.16 b.) 0.31 c.) 1.4 d.) 0.94 e.) 0.71
B. 0.31, 0.47*2/3
Which of the following statements is true? A. If Q<K, it means the reverse action will proceed to form more reactants. B. If Q=K, it means the reaction is at equilibrium C. If Q>K, it means the forward reaction will proceed to form more products D. All of the above C. None of the above are true
B. If Q=K, it means the reaction is at equilibrium
Which of the following statements is FALSE? A--The average rate of a reaction decreases during a reaction. B--The half life of a first order reaction is dependent on the initial concentration of reactant. C--The rate of zero order reactions are not dependent on concentration. D--It is not possible to determine the rate of a reaction from its balanced equation. E--None of the statements are FALSE.
B. The half-life of a first order reaction is dependent on the initial concentration of reactant.
Give the characteristics of a first-order reaction having only one reactant. a. the rate of the reaction is proportional to the square root of the concentration of the reactant b. the rate of the reaction is directly proportional to the concentration of the reactant c. the rate of the reaction is not proportional to the concentration of the reactant d. the rate of the reaction is proportional to the natural logarithm of the concentration of the reactant e. the rate of the reaction is proportional to the square of the concentration of the reactant
B. The rate of the reaction is directly proportional to the concentration of the reactant
Which of the following statements is true? A. Dynamic equilibrium indicates that the amount of reactants and products are equal. B. A reaction quotient (Q) larger than the equilibrium constant (K) means the reaction will favor the production of more products. C. The equilibrium constant for the forward reaction is equal to the equilibrium constant for the reverse reaction. C. Dynamic equilibrium occurs when the rate of the forward reaction equals the rate of the reverse reaction. D. All of the above
D. All the above
Polyprotic oxyacid
H2CO3, H3PO4, H2PO4-,H2SO4, H2S
Which of the following species is amphoteric?
H2O HCO3-, H2PO4-, HPO42-, other anions derived from diprotic or triprotic acids
a sample of rainwater has a pH of 3.5. what ion is sure to be present in relatively large concentration in this rain sample?
H3O+
All of the following are strong acids
HCl HBr HI HClO4 HNO3 H2SO4 HClO3
A catalyst ____ the rate of the reaction by ____.
Increases, lowering the energy of the activation
Which of the following statements is false regarding the relative values of K?
Kc > 1 Reaction is strongly product favored. •very little reactant remains•often written as a forward reaction only. •assume reaction goes to completion. Kc < 1 Reaction is strongly reactant favored.• very little product forms •usually written as "no reaction"or NR Kc ≈ 1 Reactants & products present at equilibrium. •use equilibrium methods discussed here.
Exothermic reactions
Kc decreases as T increases. •Are less product favored at higher T.
Endothermic reactions
Kc increases as T increases. •Are more product favored at higher T.
strong base
LiOH Lithium hydroxide NaOHSodium hydroxide KOHPotassium hydroxide
Which of the following statements is TRUE? A. The rate constant does not depend on the activation energy for a reaction where the products are lower in energy than the reactants. B. Rate constants are temperature dependent. C. A catalyst raises the activation energy of a reaction. D. The addition of a homogeneous catalyst does not change the activation energy of a given reaction.
Rate constant is temperature dependent
K >Q K< Q
Reaction goes to the right. Reaction goes to the left.
Given the following rate law how does the rate of reaction change if the concentration of Y is doubled rate=k[x]^2[Y]^3
The rate of reaction will increase by a factor of 8
Chemical equilibrium is the result of ____.
When the forward and reverse rates of an eq. reaction is equal.
A lewis base A lewis acid
a compound capable of donating a pair of electrons a compound capable of accepting a pair of electrons
Give the characteristics of a strong acid
completely dissociates into ions electrical conductivity - high concentration of ions present a higher rate of reaction lower pH than weak acid
What is the change in n for the following equation in regards to Kc and Kp.
moles of product - moles of reactant
Neutral solution Acidic solution Basic solution
pH of 7 pH of lower than 7 pH of higher than 7
More products than reactants = More reactants than products =
product favored, reactant favored
Kc=
product/ reactant
The rate-determining step is the ___ step in a reaction mechanism.
slowest