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Y12 IB SL Equilibrium and Acids review

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  • Which of the following is a true statement about the role of catalysts in a reaction?
    catalysts effectively lower the temperature
    catalysts more effectively lower the Ea in reverse direction
    catalysts increase rate of forward and reverse reaction
    catalysts more effectively lower the Ea in forward direction
  • Which of the following is a strong base?
    aluminum hydroxide
    sodium carbonate
    ammonia
    barium oxide
  • In the following Maxwell–Boltzmann energy distribution curve, What may have caused the change with the dashed line?
    additon of catalyst
    decreased pressure
    lower temperature
    higher temperature
  • Distinguish between the terms reaction quotient, Q, and equilibrium constant, Kc.
    Q: non-equilibrium concentrations AND Kc: equilibrium concentrations
  • (N2) reacts with (H2) to form (NH3). At 200°C in a closed container, 1.0 atm of nitrogen gas is mixed with 2.0 atm of H2 gas. At equilibrium, the total pressure is 1.9 atm. Calculate the partial pressure of hydrogen gas at equilibrium
    0.35 atm ((1.0−x)+(2.0−3x)+2x=1.9 atm; −1.9=2x⟹1.1=2x⟹x=0.55)
  • a substance that takes part in and undergoes change in a chemical reaction
    reactant
  • What is the concentration of the sulphuric acid solution, if 100 ml of the solution is neutralised by 50 ml of 0.5 M Ba(OH)2 solution?
    0.25 M
  • Which statement about chemical equilibria implies they are dynamic?
    The position of equilibrium constantly changes.
    The reactants and products continue to react.
    The rates of forward and backward reactions change
    The concentrations of the reactants and products continue to
  • For the following reaction, which direction will the equilibrium shift if pressure is decreased?
    right
    stays the same
    more information is needed
    left
  • the name of the liquid in the receiving flask when doing a titration
    indicator
    analyte
    titrant
    acid
  • A substance that forms in a chemical reaction
    product
  • Define endpoint
    the pH at which the indicator changes colour
  • The equilibrium 2H2 (g) + N2 (g) ⇌ N2H4 (g) has an equilibrium constant, K, at 150 °C. What is the equilibrium constant at 150 °C, for the reverse reaction? N2H4 (g) ⇌ 2H2 (g) + N2 (g)
    2K
    K^2
    −K
    K−1
  • What gas is produced when potassium hydrogen carbonate is reacted with hydrobromic acid?
    hydrogen
    carbon dioxide
    oxygen
    potassium
  • What is the molarity of the solution of barium hydroxide, if 35 ml of 0.1 M HCl is used in the titration of 25 ml of the barium hydroxide solution?
    0.07 N
  • units for concentration
    mol/dm^3
    L/g
    kPa/g
    dm^3/mol
  • Which of the following forms.a precipitate
    BaSO4
    (NH4)2SO3
    Sr(NO3)2
    Na3PO4
  • Which step in a multi-step reaction is the rate determining step?
    The step with the lowest activation energy
    The last step
    The first step
    The step with the highest activation energy
  • If the temperature of the reaction is changed to 300 °C, predict, stating a reason in each case, whether the equilibrium concentration of SO2Cl2 and the value of will Kc increase or decrease.
    K increases, SO2Cl2 decreases
    they both increase
    both decrease
    K decreases, SO2Cl2 increases
  • What gas is produced when zinc is reacted with a strong acid?
    carbon monoxide
    carbon dioxide
    hydrogen
    oxygen
  • What happens when a system at equilibrium is subjected to a stress (change)?
    The equilibrium will shift in order to reduce that stress
  • The reaction below represents the Haber process for the industrial production of ammonia. N2(g) + 3H2(g) <====> 2NH3(g) ∆H = -92 kJ. How can more ammonia be produced?
    higher pressure
    removing nitrogen
    lower temperature
    increase volume
  • What is the conetration of OH- in a 1.2 M solution of KOH?
    1.2 M
  • What is the pH of a 0.020 M solution of hydrobromic acid?
    1.70
  • Which of the following is NOT a strong acid?
    HCl
    HNO3
    H2PO4
    HI
  • What makes an effective collision?
    high temperature
    When molecules collide with proper orientation and enough ki
    When molecules collide
    When molecules collide with proper orientation
  • Define equivalence point
    when the moles of acid = moles of base
  • When concentration is increased on a system at equilibrium, what changes?
    The equilibrium concentrations will change, but the equilibrium constant Keq (ratio of products/reactants at equilibrium) will not change
  • What is the conetration of OH- in a 1.2 M solution of Ba(OH)2?
    2.4 M
  • adding heat
    no change
    to the left
    to the right
    more information needed
  • Which variable affects the equilibrium constant, Kc?
    catalyst
    concentration of reactants
    temperature
    pressure
  • when an acid and a base react to form water and a salt
    neutralization
    alkalization
    acidification
    deposition
  • Increasing the volume of the container
    no change
    to the right
    to the left
    more information needed
  • For the following reaction, which direction will the equilibrium shift if fluorine is removed?
    left
    right
    stays the same
    more information is needed
  • In the following list, which is the strongest acid?
    HBrO4
    HBrO
    HBrO2
    HBrO3
  • What is the ratio of the initial rate of the appearance of water to the initial rate of disappearance of oxygen?
    2:2
    1:1
    2:1
    1:2
  • If the pressure on a system at this equilibrium. (2H2(g) + O2(g) <--> 2 H2O(g))is increased, what direction will the equilibrium shift towards?
    toward reactants
    toward products
    no change
    cannot be determined
  • True or false: When a reaction is at equilbrium, the cocentration of products and reacts are equal
    true
    false
  • For the reaction: Ag+ (aq) + Cl-(aq) <--> AgCl(s) ΔH = -127kJ/mol In which direction does the equilibrium shift as a result of adding NaCl?
    to the right
  • Equilibrium is reached in chemical reactions when:
    The rates of the forward and reverse reactions become equal.
    The temperature shows a sharp rise.
    All chemical reactions stop
    The concentrations of reactants and products become equal.
  • Consider the following equilibrated system: 2NO2(g) <--> 2NO(g) + O2(g). If the Kp value is 0.648, find the equilibrium pressure of the O2 gas if the NO2 gas pressure is 0.520 atm and the PNO is 0.300 atm at equilibrium.
    1.95 atm
    1.12 atm
    26.6 atm
    0.216 atm
  • Which of the following would have the highest H+ concentration?
    0.80 M HBr
    2.0 M of HF
    1.0 M H2SO4
    5.0 M NaOH
  • State the effect of an increase in the total pressure on the equilibrium constant, Kc.
    no effect
  • Adding NaCl
    to the left
    more information needed
    no change
    to the right
  • A reversible reaction has a reaction quotient, Q, of 4.5 and equilibrium constant, Kc, of 6.2. 2A (g) ⇌ A2 (g) Which statement describes the reaction at this time?
    At equilibrium, concentration reactant > concentrat product
    Concentration of reactant > concentration of product
    The system has reached equilibrium.
    Rate of forward rxn is greater than rate of reverse rxn
  • For the reaction: 2HI (g) <--> H2 (g) + I2 (g). If the Ksp is 0.020 and the Qsp is 0.34, the reaction will proceed which direction?:
    Proceed to the left
  • What is the H+ concentration of an acid with a pH of 2.78
    1.7E-3M
  • Name two ways to increase ammonia production in Born haber process
    cool to collect ammonia, add nitrogen or hydrogen, add catalyst, increase temperature (even though exothermic reaction)
  • What is the effect of increasing temperature on the equilibrium?
    shifts left; K decreases
    shifts right; K increases
    shifts left; K doesn't change
    shifts right; K doesn't change
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