Chemical Reactions

Question 1

EFFECT ON EQUILIBRIUM BY:
-Changing Temperature
-Changing Pressure
-Changing Concentration
-Using a Catalyst
(Explain Using Collision Theory)

Answer 1

Changing Temperature:

Effect: Increasing temperature favors endothermic reactions, while decreasing temperature favors exothermic reactions.

Collision Theory Explanation: Higher temperature increases the kinetic energy of particles, leading to more frequent and energetic collisions. This increases the rate of reaction in the endothermic direction.

Changing Pressure:

Effect: Only affects equilibrium involving gases.
Increasing pressure shifts equilibrium towards the side with less moles of gas.

Collision Theory Explanation: Increasing pressure decreases the volume, causing the concentration of gases to increase. This leads to more frequent collisions, favoring the side with fewer gas molecules to alleviate the pressure.

Changing Concentration:

Effect: Increasing concentration of reactants shifts equilibrium towards products, and vice versa.

Collision Theory Explanation: Higher concentration increases the frequency of collisions, leading to more successful collisions and higher rate of reaction in the direction that consumes the added reactant.

Using a Catalyst:

Effect: Catalyst speeds up both forward and backward reactions equally, leading to faster attainment of equilibrium.

Collision Theory Explanation: Catalysts provide an alternate reaction pathway with lower activation energy. This increases the frequency of successful collisions in both directions, leading to faster establishment of equilibrium.

Question 2

Haber Process
- Symbol Equation
- Sources of reactants
- Conditions (Temp & Pressure)
- Catalyst Used

Answer 2

Symbol Equation:
N2(g) + 3H2(g) ⇌ 2NH3(g)

Sources of Reactants:
Nitrogen is sourced from the air.
Hydrogen is obtained from natural gas or steam reforming.

Conditions:
400-450°C
High pressure, around 200 atm.

Catalyst Used: Iron catalyst

Question 3

Contact process
- Symbol Equation
- Sources of reactants
- Conditions (Temp & Pressure)
- Catalyst Used

Answer 3

Contact Process:

Symbol Equation:
2SO2(g) + O2(g) ⇌ 2SO3(g)

Sources of Reactants:
Sulfur dioxide is from burning sulfur or roasting metal sulfides.
Oxygen is sourced from the air.

Conditions:
400-450°C
Moderate pressure, 2 atm.

Catalyst Used:
Vanadium(V) oxide (V2O5)

Question 4

Why are the typical conditions chosen for the Haber process and the Contact process and how do these conditions affect reaction speed, equilibrium position, safety, and cost?

Answer 4

The Haber Process uses high pressure and moderate temperature to speed up the reaction, favoring ammonia production for higher yields. Safety precautions are needed for handling high pressure and toxic reactants, while the chosen conditions balance yield and energy costs.

The Contact Process employs high temperature and moderate pressure to enhance the reaction rate and yield of sulfuric acid. Safety measures are crucial due to corrosive reactants and high temperatures, while optimal conditions prioritize efficiency and cost-effectiveness in production.

Question 5

IDENTIFYING REDOX REACTIONS

• How to identify Oxidation
• How to identify Reduction

Answer 5

Using Acidified Aqueous Potassium Manganate(VII)(KMnO₄) acts as an oxidizing agent and changes color during redox reactions.

• It is purple in its oxidized form (MnO₄⁻) and turns colorless upon reduction to manganese(II) ions (Mn²⁺).

Using Aqueous Potassium Iodide (KI) acts as a reducing agent and undergoes redox reactions with oxidizing agents.

• It is colorless in its reduced form (I⁻) and produces a brown color upon oxidation to iodine (I₂).