6.3 Reversible Reactions and Equilibrium
Click on any question below to reveal the interactive flashcard answer key:
20. What symbol is used to show that a chemical reaction is reversible?
The symbol ⇌.
21. Describe the effect of heat on hydrated copper(II) sulfate.
Heating hydrated copper(II) sulfate drives off the water to form anhydrous copper(II) sulfate; the color changes from blue to white.
22. Describe the effect of adding water to anhydrous copper(II) sulfate.
Adding water to white anhydrous copper(II) sulfate turns it back into blue hydrated copper(II) sulfate.
23. Describe the effect of heat on hydrated cobalt(II) chloride.
Heating hydrated cobalt(II) chloride turns it from pink to blue anhydrous cobalt(II) chloride.
24. Describe the effect of adding water to anhydrous cobalt(II) chloride.
Adding water to blue anhydrous cobalt(II) chloride turns it back into pink hydrated cobalt(II) chloride.
25. When is a reversible reaction in a closed system at equilibrium regarding reaction rates?
When the rate of the forward reaction is equal to the rate of the reverse reaction.
26. When is a reversible reaction in a closed system at equilibrium regarding concentration?
When the concentrations of reactants and products are no longer changing.
27. Predict how increasing temperature affects the position of equilibrium.
Increasing temperature shifts the equilibrium in the direction of the endothermic reaction.
28. Predict how decreasing temperature affects the position of equilibrium.
Decreasing temperature shifts the equilibrium in the direction of the exothermic reaction.
29. Predict how increasing pressure affects the position of equilibrium in a gaseous reaction.
Increasing pressure shifts the equilibrium toward the side with the fewer number of gas molecules.
30. Predict how decreasing pressure affects the position of equilibrium in a gaseous reaction.
Decreasing pressure shifts the equilibrium toward the side with the greater number of gas molecules.
31. Predict how changing concentration affects the position of equilibrium.
Increasing the concentration of a reactant shifts the equilibrium toward the products; increasing product concentration shifts it toward the reactants.
32. What is the effect of using a catalyst on the position of equilibrium?
A catalyst has no effect on the position of equilibrium; it only increases the rate at which equilibrium is reached.
33. State the symbol equation for the Haber process.
N2(g) + 3H2(g) ⇌ 2NH3(g)
34. What are the sources of hydrogen and nitrogen for the Haber process?
Hydrogen is sourced from methane, and nitrogen is sourced from the air.
35. State the typical conditions used in the Haber process.
450 °C, 20,000 kPa (200 atm), and an iron catalyst.
36. State the symbol equation for the conversion of sulfur dioxide to sulfur trioxide in the Contact process.
2SO2(g) + O2(g) ⇌ 2SO3(g)
37. What are the sources of sulfur dioxide and oxygen for the Contact process?
Sulfur dioxide is sourced from burning sulfur or roasting sulfide ores, and oxygen is sourced from the air.
38. State the typical conditions for the sulfur trioxide stage of the Contact process.
450 °C, 200 kPa (2 atm), and a vanadium(V) oxide catalyst.
39. Why are the specific typical conditions chosen for the Haber and Contact processes?
They are chosen to balance the rate of reaction, the yield (position of equilibrium), safety considerations, and economic costs.