RATES OF REACTION & CHEMICAL EQUILIBRIUM
- Consider the following two ways of producing hydrogen (H2) gas in the laboratory:
In test tube B, H2(g) is produced at a faster rate than in test tube A.
1.1Give three reasons why H2(g) is produced at a faster rate in test-tube B.(6)
1.2Mention 2 ways, other than those mentioned in 1.1 above, of increasing the rate of the reaction in test-tube B. (4)
2.The following reversible reaction reaches equilibrium in a closed container:
N2(g) + 3H2(g) 2NH3(g)ΔH < 0
2.1What is the meaning of the term “reaches equilibrium”?(2)
2.2State Le Chatelier’s Principle in words.(4)
2.3How would the equilibrium concentration of the ammonia be affected by
2.3.1an increase in temperature(2)
2.3.2an increase in pressure(2)
2.3.3increasing the concentration of the nitrogen(2)
2.3.4the addition of an iron catalyst(2)
3.A learner prepares a saturated aqueous solution of barium chloride (BaCl2) in a test-tube. The following equilibrium is established:
BaCl2(s) Ba2+(aq) + 2Cl-(aq)ΔH < 0
3.1 The graph illustrates the reaction rate versus time relationship for this equlibrium:
3.1.1Write down the equation for the reaction represented by the solid line.(2)
3.1.2What does the horizontal part of the graph after tx mean?(2)
3.2 How would the equlibrium concentration of Cl-(aq) ions be affected if:
(Only answer INCREASES, DECREASES or REMAINS THE SAME)
3.2.1the test-tube is heated?(2)
3.2.2a few drops of saturated Ba(NO3)2 solution were added to the test-tube?(2)
3.2.3more BaCl2(s) is added to the test-tube?(2)
4.The accompanying energy diagram shows two reactions X and Y on the same axis.
4.1Which one of the two reactions has a positive heat of reaction?(2)
4.2Which one of the two reactions has the greatest activation energy?(2)
4.3If reaction Y is reversible, is the reverse reaction exo- or endothermic?(2)
4.4How will the reaction of X be affected by heating?(1)
4.5How will the reaction of Y be affected by heating?(1)