Equilibrium (paper 1 style questions)

Beschreibung

International baccalaureate Chemistry (Equilibrium) Quiz am Equilibrium (paper 1 style questions), erstellt von Emine Afiyet Fra am 15/09/2013.
Emine Afiyet Fra
Quiz von Emine Afiyet Fra, aktualisiert more than 1 year ago
Emine Afiyet Fra
Erstellt von Emine Afiyet Fra vor etwa 11 Jahre
294
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Zusammenfassung der Ressource

Frage 1

Frage
Which statement is true about chemical reactions at equilibrium?
Antworten
  • The forward and backward reactions proceed at equal rates
  • The forward and backward reactions have stopped
  • The concentrations of the reactants and products are equal
  • The forward reaction is exothermic

Frage 2

Frage
Chemical equilibrium is referred to as dynamic because, at equilibrium, the...
Antworten
  • equilibrium constant changes
  • reactants and products keep reacting
  • rates of the forward and backward reactions change
  • concentrations of the reactants and products continue to change

Frage 3

Frage
What is the equilibrium expression for the reaction: N2 + 3H2 --> 2NH3 (all in the gaseous state)?
Antworten
  • [NH3]^2/[N2][H2]^3
  • 2[NH3]/3[N2][H2]
  • [NH3]/[N2][H2]
  • 2[NH3]/[N2][H2]

Frage 4

Frage
For a reaction which goes to completion, the equilibrium constant, Kc, is:
Antworten
  • more than 1 (Kc >>1)
  • less than 1 (Kc
  • = 1
  • = 0

Frage 5

Frage
The equilibrium constant for the reaction below is 1.0 x 10^-14 at 25oC and 2.1 x 10^-14 at 35oC. What can be concluded from this information? 2H2O (l) H3O+ (aq) + OH- (aq)
Antworten
  • The ionization of water is endothermic
  • [H3O+] decreases as the temperature is raised
  • Water is a stronger electrolyte at 25oC
  • [H3O+] is greater than [OH+] at 35oC

Frage 6

Frage
Ethanol is manufactured from ethene using the reaction: C2H4 + H2O C2H5OH (Delta-H = -46 KJ) Which conditions favour the highest yield of ethanol?
Antworten
  • High pressure and low temperature
  • High pressure and high temperature
  • Low pressure and low temperature
  • Low pressure and high temperature

Frage 7

Frage
N2O4 and NO2 produce an equilibrium mixture according to the equation: N2O4 2NO2 (Delta-H = 57.2 KJ/mol) An increase in the equilibrium concentration of NO2 can be produced by increasing which of the factors below? 1) Pressure 2) Temperature
Antworten
  • 1 only
  • 2 only
  • both 1 and 2
  • neither 1 or 2

Frage 8

Frage
Which changes will increase the amount of SO3 (g) at equilibrium? 2SO2 + O2 2SO3 (Delta-H = -197KJ) 1) increasing temperature 2) decreasing volume 3) adding a catalyst
Antworten
  • 1 only
  • 2 only
  • 1 and 3 only
  • 1, 2 and 3

Frage 9

Frage
For the reaction N2 + 3H2 2NH3 (Delta-H = -92 KJ) What conditions will produce the highest percentage of NH3 at equilibrium?
Antworten
  • High pressure and high temperature
  • High pressure and low temperature
  • Low pressure and high temperature
  • Low pressure and low temperature

Frage 10

Frage
Hydrogen and iodine react in a closed vessel to form hydrogen iodide. H2 + I2 2HI at 350oC, Kc = 60 at 445oC, Kc = 47
Antworten
  • Increased temperature as the forward reaction is exothermic, and increased pressure as there are two gaseous reactants and only one gaseous product
  • Increased temperature as the forward reaction is endothermic, and pressure has no effect as there are equal amounts, in mol, of gaseous reactants and products
  • Decreased temperature as the forward reaction is exothermic, and decreased pressure as there are 2 moles of gaseous product but only 1 mole of each gaseous reactant
  • Decreased temperature as the forward reaction is exothermic, and pressure has no effect as there are equal amounts, in mol, of gaseous reactants and products

Frage 11

Frage
An increase in temperature increases the amount of chlorine present in the following equilibrium. PCL5 (s) PCL3 (l) + CL2 (g) What is the best explanation for this?
Antworten
  • The higher temperature increases the rate of the forward reaction only.
  • The higher temperature increases the rate of the reverse reaction only
  • The higher temperature increases the rate of both reactions but the reverse reaction is affected more than the forward
  • The higher temperature increases the rate of both reactions but the forward reaction is affected more than the reverse

Frage 12

Frage
The reaction between sulfur dioxide and oxygen (the contact process) occurs according to the equation below: 2SO2 + O2 2SO3 (Delta-H = -197) A higher equilibrium concentration of SO3 will be produced by all of the following changes in a reaction conditions except...
Antworten
  • increasing pressure
  • adding more O2
  • adding a catalyst
  • decreasing the temperature

Frage 13

Frage
The reaction between methane and hydrogen sulfide is represented by the equation below: CH4 + 2H2S CS2 + 4H2 What is the equilibrium expression for this reaction?
Antworten
  • [CS2][H2]/[CH4][H2S]
  • 4[CS2][H2]/2[CH4][H2S]
  • [CS2] 4[H2]/[CH4] + 2[H2S]
  • [CS2][H2]^4/[CH4][H2S]^2

Frage 14

Frage
At 35oC, Kc = 1.6 x 10^-5 mol/dm^3 for the reaction: 2NOCL 2NO + Cl2 Which relationship must be correct at equilibrium?
Antworten
  • [NO] = [NOCl]
  • 2[NO] = [Cl2]
  • [NOCl]
  • [NO]
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