1. (Lv.1) Which of the following is the correct K_c expression for the reversible reaction 2HBr(g) --> H₂(g) + Br₂(g)?

2. (Lv.1) For the K_c expression derived from question 1, what are the correct K_c units?

3. (Lv.2) When aqueous ammonia, NH₃(aq) is added to Zinc Hydroxide, Zn(OH₂) in large excess, a miraculous phenomenon occurs where the precipitate dissolves! The reversible equilibrium is given by: Zn(OH)₂(s) + 4NH₃(aq) --> Zn(NH₃)₄²⁺(aq) + 2OH^-(aq). What is the correct K_c expression for the above dissolution reaction?

4. (Lv. 1) For the K_c expression derived from question 3, what are the correct K_c units?

5. (Lv. 2) A metal displacement reaction occurs when a more reactive metal is exposed to a "salt solution" of the less reactive metal. For a solution of Iron(III) Nitrate, Zinc metal was added, prompting such a reaction to take place. By means of writing the ionic equation for this displacement reaction, derive the K_c expression for this particular metal displacement reaction.

6. (Lv. 1) For the K_c expression derived from question 5, what are the correct K_c units?

7. (Lv. 1) In an experiment to study the formation of Hydrogen Iodide, I₂(g) + H₂(g) --> 2HI(g), the equilibrium concentrations of I₂(g), H₂(g) and HI(g) were 1.06x10^-3moldm^-3, 6.50x10^-5moldm^-3 and 1.80x10^-3moldm^-3 respectively. Calculate the K_c of this equilibrium reaction, assuming no temperature changes.

8. (Lv. 2) At a certain temperature, the value of K_c for the equilibrium system HCN(aq) + H₂O(l) --> CN^-(aq) + H₃O⁺(aq) is 6.20x10^-10moldm^-3. What is the new K_c value for the following reaction: 2HCN(aq) + 2H₂O(l) --> 2CN^-(aq) + 2H₃O⁺(aq)?

9. (Lv. 2) 2 equilibria are as shown below:

Equilibria I: 2X₂(g) + Y₂(g) --> 2X₂Y

Equilibria II: X₂Y --> X₂(g) + 1/2Y₂(g)

If the value of K_c for the 1st equilibria is 2M, under the same conditions of temperature, what is the value of K_c for equilibria II?

10. (Lv. 2) At a certain temperature, the dissolution of 1 mole of AgCl(s) in an aqueous medium has a K_c value of 1.60x10^-10mol²dm^-6. What is the value of K_c for the precipitation of 4 moles of AgCl(s) from its constituent (aq) ions?

11. (Lv. 2) A chemist employed by the National Environment Agency (NEA) is tasked to study catalytic converters in relation to urban smog. The chemist is tasked to find K_c for the following equilibrium reaction: 2NO₂(g) --> 2O₂(g) + N₂(g)

Given the following data:

2NO₂(g) --> 2NO(g) + O₂(g) K_c=1.10x10^-5moldm^-3

0.5O₂(g) + 0.5N₂(g) --> NO(g) K_c=4.80x10^-10

Calculate unknown K_c for the reaction that the chemist is tasked to study.

12. (Lv. 2) The depletion of ozone in the upper atmosphere is a very pressing environmental issue. The overall equation is O₃(g) --> O(g) + O₂(g).

Given the following data:

NO₂(g) --> NO(g) + O(g) K_c=7.80x10^-45moldm^-3

NO₂(g) + O₂(g) --> NO(g) + O₃(g) K_c=1.70x10³³

Calculate the unknown K_c for the depletion of ozone.

13. (Lv. 3) At temperature TK, 3 equilibrium constants for their respective equilibrium systems are as shown below:

CO₂(g) + H₂(g) --> CO(g) + H₂O(g) K₁=0.2

C(s) + CO2(g) --> 2CO(g) K₂= 6.2moldm^-3

C(s) + 1/2O₂(g) --> CO(g) K₃=3.30x10⁴(moldm^-3)^0.5

Using the above, what is the value of K_c for the following equilibrium: 3CO₂(g) + H₂(g) --> 3CO(g) + H₂O(g) + O₂(g) at temperature TK?

14. (Lv. 1) Calcium Carbonate, CaCO₃ readily decomposes upon heating to give solid calcium oxide and gaseous carbon dioxide. Which of the following is the correct expression for K_p?

15. (Lv. 1) For the K_p expression derived from question 13, what are the correct K_p units?

16. (Lv. 1) For the following reversible reaction: 4NH₃(g) + 7O₂(g) --> 4NO₂(g) + 6H₂O(l), what is the correct K_p expression?

17. (Lv. 1) For the K_p expression derived from question 14, what are the correct K_p units?

18. (Lv. 2) Calculate K_p for the reaction 2IF₃(s) + 3Ne(g) --> 3NeF₂(s) + I₂(s), given that the equilibrium amounts of Ne, NeF₂ and I₂ are all the same, while Ne exerts a pressure of 2.90kPa at equilibrium.

19. (Lv. 2) At 1000^oC, the following reaction C(s) + 2H₂(g) --> CH₄(g) has K_p of 0.262atm^-1. At equilibrium, the partial pressure of Methane is 12.2kPa. What is the equilibrium partial pressure of Hydrogen?

20. (Lv. 2) At a certain temperature, the value of K_p for the reversible equilibrium reaction 3O₂(g) --> 2O₃(g) is 8.00atm^-1. What is the value of K_p for the following reaction: 2O₃(g) --> 3O₂(g)?

21. (Lv. 2) A gaseous equilibrium mixture in a flask at temperature T was found to consist of 0.50mol of SO₂(g), 0.12mol of O₂(g) and 5.0mol of SO₃(g). The total pressure inside the flask was 800kPa.

22. (Lv. 1) The water-gas shift reaction plays a central role in the chemical methods for obtaining cleaner fuels from coal. The reaction is given by: CO(g) + H₂O(g) --> H₂(g) + CO₂(g). At a temperature of TK, the K_p is 2.7. Calculate the value of K_c for the same reaction.

23. (Lv. 1) 2.00moles each of SO₂(g), SO₃(g) and O₂(g) are mixed and allowed to react in a 2l container. If the K_c of the reaction: 2SO₂(g) + O₂(g) --> 2SO₃(g) is 0.8moldm^-3, what will happen to the chemical system in this current state?

24. (Lv. 1) At 425^oC, for the following reaction 2HBr(g) --> H₂(g) + Br₂(g), K_p=4.18x10^-9. In 1 experiment, 1.00atm of HBr(g), 0.010atm of H₂(g) and 0.010atm of Br₂(g) were introduced into a reaction vessel. What will happen to this chemical system?

25. (Lv. 1) At room temperature, the equilibrium constant, K_c for the following reaction 2NO(g) --> O₂(g) + N₂(g) is 1.4x10³⁰. 560g of N₂(g) was mixed with 320g of O₂(g) and 90g of NO(g). What will happen to this chemical system?