Quiz
Equilibrium (paper 1 style questions)
Questions in this quiz (14)
1Which statement is true about chemical reactions at equilibrium?
- AThe forward and backward reactions proceed at equal rates
- BThe forward and backward reactions have stopped
- CThe concentrations of the reactants and products are equal
- DThe forward reaction is exothermic
2Chemical equilibrium is referred to as dynamic because, at equilibrium, the...
- Aequilibrium constant changes
- Breactants and products keep reacting
- Crates of the forward and backward reactions change
- Dconcentrations of the reactants and products continue to change
3What is the equilibrium expression for the reaction: N2 + 3H2 --> 2NH3 (all in the gaseous state)?
- A[NH3]^2/[N2][H2]^3
- B2[NH3]/3[N2][H2]
- C[NH3]/[N2][H2]
- D2[NH3]/[N2][H2]
4For a reaction which goes to completion, the equilibrium constant, Kc, is:
- Amore than 1 (Kc >>1)
- Bless than 1 (Kc
- C= 1
- D= 0
5The 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)- AThe ionization of water is endothermic
- B[H3O+] decreases as the temperature is raised
- CWater is a stronger electrolyte at 25oC
- D[H3O+] is greater than [OH+] at 35oC
6Ethanol is manufactured from ethene using the reaction:
C2H4 + H2O C2H5OH (Delta-H = -46 KJ)
Which conditions favour the highest yield of ethanol?- AHigh pressure and low temperature
- BHigh pressure and high temperature
- CLow pressure and low temperature
- DLow pressure and high temperature
7N2O4 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- A1 only
- B2 only
- Cboth 1 and 2
- Dneither 1 or 2
8Which 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- A1 only
- B2 only
- C1 and 3 only
- D1, 2 and 3
9For the reaction N2 + 3H2 2NH3 (Delta-H = -92 KJ)
What conditions will produce the highest percentage of NH3 at equilibrium?- AHigh pressure and high temperature
- BHigh pressure and low temperature
- CLow pressure and high temperature
- DLow pressure and low temperature
10Hydrogen and iodine react in a closed vessel to form hydrogen iodide.
H2 + I2 2HI
at 350oC, Kc = 60
at 445oC, Kc = 47- AIncreased temperature as the forward reaction is exothermic, and increased pressure as there are two gaseous reactants and only one gaseous product
- BIncreased temperature as the forward reaction is endothermic, and pressure has no effect as there are equal amounts, in mol, of gaseous reactants and products
- CDecreased 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
- DDecreased temperature as the forward reaction is exothermic, and pressure has no effect as there are equal amounts, in mol, of gaseous reactants and products
11An 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?- AThe higher temperature increases the rate of the forward reaction only.
- BThe higher temperature increases the rate of the reverse reaction only
- CThe higher temperature increases the rate of both reactions but the reverse reaction is affected more than the forward
- DThe higher temperature increases the rate of both reactions but the forward reaction is affected more than the reverse
12The 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...- Aincreasing pressure
- Badding more O2
- Cadding a catalyst
- Ddecreasing the temperature
13The reaction between methane and hydrogen sulfide is represented by the equation below:
CH4 + 2H2S CS2 + 4H2
What is the equilibrium expression for this reaction?- A[CS2][H2]/[CH4][H2S]
- B4[CS2][H2]/2[CH4][H2S]
- C[CS2] 4[H2]/[CH4] + 2[H2S]
- D[CS2][H2]^4/[CH4][H2S]^2
14At 35oC, Kc = 1.6 x 10^-5 mol/dm^3 for the reaction:
2NOCL 2NO + Cl2
Which relationship must be correct at equilibrium?- A[NO] = [NOCl]
- B2[NO] = [Cl2]
- C[NOCl]
- D[NO]
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- International baccalaureate Chemistry (Equilibrium) Quiz on Equilibrium (paper 1 style questions), created by Emine Afiyet Fra on 15/09/2013.
- Author
- Emine Afiyet Fra
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- English
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