Chem Test 3
A decrease in the H⁺ concentration by a factor of 100 implies which of the following? A) The pH increases by 2. B) The pH decreases by 2. C) The pH increases by a factor of 100. D) The pH decreases by a factor of 100.
A
Consider the following chemical reaction at equilibrium: 2NO₂(g) ⇌ N₂O₄(g) If the container's volume is increased by a factor of 2, in which direction will the equilibrium shift? A) reactants B) product C) neither the reactants nor the product
A
Consider the following chemical reaction at equilibrium: 2NO₂(g) ⇌ N₂O₄(g) ∆H°rxn < 0 If the temperature is increased by 20 K while the volume is kept constant, in which direction will the equilibrium shift? A) reactants B) product C) neither the reactants nor the product
A
Consider the following reaction at equilibrium CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g) If CO(g) is removed, in which direction will the equilibrium shift? A) reactants B) products C) no change
A
If the pressure for a system is increased via decreased volume, the reaction shifts to the side with:
fewer gas moles
If Kc is 14 for the reverse reaction, what is Kc for the forward reaction at the same temperature?
1/14
Consider the following reaction at equilibrium: N₂O₄(g) ⇌ 2NO₂(g) The ∆H° for this reaction is > 0. If the temperature is increased by 20.0 K while the volume is kept constant, how will K(eq) change? A) increase B) decrease C) stay the same
A
For the reaction below, Q = 600. What must happen for the reaction to reach equilibrium? 2 A (g) + B (s) ⇌ 2 C (s) + D (g) Kp = 8210 A) The reaction needs to shift in the forward direction. B) The reaction needs to shift in the reverse direction. C) The reaction is already at equilibrium and no shift needs to take place. D) There is not enough information to determine how the reaction will reach equilibrium.
A
HBr is an Arrhenius acid because A) it produces hydronium ions in solution. B) it produces hydroxide ions in solution. C) it is a polar molecule. D) it can dissolve in water.
A
If the reaction quotient (Q) for a given reaction is less than the equilibrium constant (K) then A) the reaction will proceed in the forward direction. B) The reaction will proceed in the reverse direction. C) the reaction is at equilibrium.
A
Rank the following solutions in order from most acidic to least acidic. A) HNO₃ > HNO₂ > NaNO₃ > NaNO₂ B) NaNO₂ > NaNO₃ > HNO₂ > HNO₃ C) HNO₃ > NaNO₃ > NaNO₂ > HNO₂ D) HNO₃ > HNO₂ > NaNO₂ > NaNO₃
A
The conjugate base of HS⁻ is A) S²⁻ B) HS²⁻ C) H₂S
A
Which of the following acids would be expected to be strongest? A) V⁴⁺ (aq) B) V³⁺ (aq) C) V²⁺ (aq) D) V⁺ (aq)
A
What happens in a conjugate acid- base pair?
A proton is accepted and an H is added. (Goes from + to 2+). OR THE OPPOSITE.
What is the acryonm for Bronsted Lowry Pairs
Acids add (Hydrogens and electrons) Bases (Basically take the air away, hydrogen and electrons are negative one more)
What is Arrhenius limited to?
Aqueous environments
What are the main differences between arrhenius and bronsted-lowry?
Arrhenius increase H+ or OH- to make H3O, while BL donates acids or accepts bases protons from or to somewhere else.
Consider the following acidic equilibrium: H₂CO₃(aq) + H₂O(l) ⇌ HCO₃⁻(aq) + H₃O⁺(aq). If you add NaHCO₃ to this solution, which of the following will occur? A) The reaction quotient will decrease. B) The reaction will shift in the reverse direction. C) The equilibrium constant will increase. D) No changes to the equilibrium positions will take place.
B
Consider the reaction below. Which species are the Brønsted-Lowry bases? HPO₄²⁻(aq) + F⁻(aq) ⇌ PO₄³⁻(aq) + HF(aq) A) PO₄³⁻, HF B) PO₄³⁻, F⁻ C) F⁻, HF D) HPO₄²⁻, F⁻
B
If the reaction quotient (Q) is larger than the equilibrium constant (K) for a reaction then which way will the reaction proceed? A) The reaction will proceed toward products B) The reaction will proceed towards reactants. C) The reaction is at equilibrium and the reaction will stop completely. D) The reaction is at equilibrium and the reaction will proceed at equal rates in the reverse and forward direction. E) The reaction equation is required to answer this question.
B
The conjugate base of HSO₃⁻ is A) HSO₃²⁻ B) SO₃²⁻ C) HSO₄⁻ D) H₂SO₃
B
Which of the following is a conjugate acid-base pair? A) CH₃NH₂, OH⁻ B) CH₃NH₂, CH₃NH₃⁺ C) H₂O, CH₃NH₃⁺ D) OH⁻, CH₃NH₃⁺
B
Why is HIO4 more acidic than HIO
Because HIO4 it contains more electronegative oxygen ions than HIO
What is conjugative acid- base associated with?
Bronsted- Lowry (borrow/ accept and donate)
Consider the following chemical reaction at equilibrium: CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g) If H₂ is removed, how will Keq for the reaction change? A) increase B) decrease C) stay the same
C
Consider the following chemical reaction at equilibrium: NH₃(aq) + H₂O(l) ⇌ NH₄⁺(aq) + HO⁻(aq) If one drop of aqueous sodium hydroxide (NaOH) is added, how will Keq for the reaction change? A) increases B) decreases C) stays the same
C
The conjugate base of HCO₃⁻ is A) HCO₃²⁻ B) H₂CO₃ C) CO₃²⁻
C
When a system is at dynamic equilibrium, A) no reactions are occurring. B) a reaction is occurring in only one direction. C) the rates of the forward and reverse reactions are equal. D) all of the reactants have been converted to products
C
Which acid-base definition classifies an acid as an electron-pair acceptor? A) Arrhenius B) Bronsted-Lowry C) Lewis
C
Which of the following is a Lewis base? A) CO₂ B) BF₃ C) NH₃ D) NO₂
C
Which of the following is a conjugate acid-base pair? A) HCN, H₃O⁺ B) H₂O, HCN C) HCN, CN⁻ D) H₃O⁺, CN⁻
C
Which of the following is a conjugate acid-base pair? A) H₂O, NH₄⁺ B) NH₃, OH⁻ C) NH₃, NH₄⁺ D) H₃O⁺, OH⁻
C
Which of the following statements best describes what occurs at equilibrium? A) The reaction has stopped so the concentrations of reactants and products do not change. B) The amount of products are equal to the amount of reactants. C) The rate of the reaction in the forward direction is equal to the rate of the reaction in the reverse direction. D) The rate constant for the forward reaction equals the rate constant for the reverse reaction.
C
Which of the following will be the strongest acid? A) PH₃ B) SiH₄ C) H₂S D) BH₃
C
Write the formula of the conjugate acid of: CH3CH2O-
C2H6O
If a reactant or product is added from a system at equilibrium, the reaction shifts towards
Consuming the extra components
In the reaction below, which reactant is the Lewis acid? Cr³⁺ + 6 H₂O → Cr(H₂O)₆³⁺
Cr3+
If the reaction quotient (Q) is equal to the equilibrium constant (K) for a reaction then A) the reaction will proceed toward products. B) the reaction will proceed towards reactants. C) the reaction is at equilibrium and the reaction will stop completely. D) the reaction is at equilibrium and the reaction will proceed at equal rates in the reverse and forward direction. E) The reaction equation is required to answer this question.
D
KOH is a Brønsted-Lowry base because A) it is a polar molecule. B) it can dissolve in water. C) it is a hydroxide donor. D) it is a proton acceptor.
D
The conjugate acid of HSO₃⁻ is A) SO₃²⁻ B) HSO₄⁻ C) HSO₃²⁻ D) H₂SO₃
D
What can be said about the concentrations of reactants relative to the concentrations of products at equilibrium? A) [Reactants] = [Products] B) [Reactants] > [Products] C) [Reactants] < [Products] D) [Products]/[Reactants] = Constant
D
What is the strongest acid among the following? A. H2S B. H2O C. H2Se D.H2Te
D
Which of the following will be the strongest acid? A) HIO B) HIO₂ C) HIO₃ D) HIO₄
D
To figure out whether an acid is strong or not (in a list) what do we resort to?
Electronegativity
If Kp decreases when temperature increase, the reaction is...
Exothermic
What is the formula of the conjugate acid of the Bronsted- Lowry Base: CO32-
HO3-
If the temperature is increased, what does the Keq do?
Increase
What is the pair of electron donor and acceptor... key word pair
Lewis
In bronsted- lowry equations, the conjugate base pair does what?
Loses an electron and loses an H
What is the one Lewis base that we need to know?
NH3
When looking at electonegativity, does the H count for anything?
No
When something starts as an acid and turns into a conjugative base, what happens in the conjugative base
One less H and one more negative charge
In brosted- lowry equations, the conjugate acid pair does what?
Receives an H plus ion and gains an ion
If Kp is greater than 0, which way is the reaction going to shift?
Right
A weaker bond means a
Stronger acid
What does Keq depend on?
Temperature
When a reaction is endothermic (+ΔH), increasing T will shift the reaction towards
The products (To the right)
When a reaction is exothermic, increasing T shifts the reaction toward:
The reactants (To the left)
If a reactant or product is removed from a system at equilibrium, the reaction shifts towards
The side with the lost components
