reversible reaction

The diagram shows the change from an anhydrous salt to its hydrated form.

Which statement is correct?

• forward reaction requires heat and water

• forward reaction requires water only

• reverse reaction requires heat and water

• reverse reaction requires water only

Steam reacts with carbon in an endothermic reaction.

C_(s) + H₂O_(g) <--> CO_(g) + H_2(g)

Which conditions of temperature and pressure would give the largest yield of hydrogen?

• temperature is high.

  pressure is high

• temperature is high

  pressure is low

• temperature is low

  pressure is high

• temperature is low

  pressure is low

The equation for the reaction is shown.

CO(g) + 2H₂(g) <--> CH₃OH(g)

The reaction is a reversible reaction.

The forward reaction is exothermic.

Which change in conditions increases the yield of methanol?

• decreasing the concentration of the carbon monoxide

• increasing the pressure

• increasing the rate of the reaction

• increasing the temperature

N₂O_{4 (g}) ⇌ 2 NO_2(g)

The reaction is reversible and endothermic.

Which conditions will give the largest yield of nitrogen dioxide, NO2 ?

• Temperature is high,

  Pressure is high

• Temperature is high,

  Pressure is low

• Temperature is low,

  Pressure is high

• Temperature is low,

  Pressure is low

When pink cobalt(II) chloride crystals are heated they form steam and a blue solid.

When water is added to the blue solid, it turns pink and becomes hot.

Which terms describe the pink cobalt(II) chloride crystals and the reactions?

• Pink cobalt(II) chloride is aqueous,

  reaction is reversible

• Pink cobalt(II) chloride is hydrated,

  reaction is reversible

• Pink cobalt(II) chloride is anhydrous,

  reaction is reversible

• Pink cobalt(II) chloride is anhydrous,

  reaction is irreversible

2SO_2(g) + O_2(g) <----> 2SO_3(g)

The forward reaction is exothermic.

Which changes would increase the equilibrium yield of SO3?

• 1,2 and 3

• 1 and 2

• 1 only

• 2 and 3

2 SO_2(g) + O_2(g) <---> 2 SO_3(g)

The forward reaction is exothermic. 

Which row shows the effect of increasing the pressure on the equilibrium mixture?

• reaction rate increases,

  amount of SO₂ decreases,

  amount SO₃ increases,

• reaction rate increases,

  amount of SO₂ inreases,

  amount SO₃ decreases,

• reaction rate is unchanged,

  amount of SO₂ decreases,

  amount SO₃ increases,

• reaction rate is unchanged,

  amount of SO₂ increases,

  amount SO₃ decreases,

Nitrogen, hydrogen and ammonia gases are placed inside a container. The container is then sealed. After some time, an equilibrium forms.

N_2(g) + 3H_2(g) <----> 2NH_3(g)

Which statement describes the equilibrium in this container?

• The amount of ammonia remains constant from the moment the container is sealed.

• The amounts of ammonia, nitrogen and hydrogen in the container are always equal.

• The rate of formation of ammonia is equal to the rate of decomposition of ammonia.

• The rate of formation of ammonia is faster than the rate of decomposition of ammonia.

CH_4(g)+H₂O_(g) <----> CO_(g)+3H_2(g)

The forward reaction is endothermic. 

Which conditions produce the highest yield of hydrogen?

• Pressure is high,

  temperature is high

• Pressure is high,

  temperature is low

• Pressure is low,

  temperature is high

• Pressure is low,

  temperature is low

The colours and the reaction of the reactants and products are shown.

The forward reaction is exothermic.

Which statement is correct?

• An increase in pressure has no effect on the equilibrium position.

• The purple colour fades when the reaction mixture is heated.

• When equilibrium is reached, both forward and reverse reactions stop.

• When more hydrogen gas is added, the purple colour increases.