⦁ When you increase the _________ of a reaction, the particles gain _________ energy. They move faster and collide with each other more often and with more _________. (p.2)

Question

⦁ _________ ________ states that an effective collision is one that transfers enough energy to break bonds and start a reaction.
⦁ _________ is a substance that has many uses. It is used in _________, cleaning products and as a refrigerant. It is manufactured by combining hydrogen and nitrogen using the ________ _________. Today, this means the reaction is performed __________________ at a temperature of 400 - 650 °C.

Answer 1

⦁ When you increase the temperature of a reaction, the particles gain kinetic energy. They move faster and collide with each other more often and with more force.
⦁ Collision theory states that an effective collision is one that transfers enough energy to break bonds and start a reaction.
⦁ Ammonia is a substance that has many uses. It is used in fertilizers, cleaning products and as a refrigerant. It is manufactured by combining hydrogen and nitrogen using the Haber process. Today, this means the reaction is performed continuously at a temperature of 400 - 650 °C.

Answer 2

⦁ Using collision theory, why do you think heating a reaction generally increases its rate? (p. 2)

⦁ Using the graph below (also found on page 3 of the lesson), what conclusions can be drawn about the depicted Haber process at different temperatures?

Answer 3

1. Why Heating a Reaction Generally Increases Its Rate (Using Collision Theory)

According to collision theory, the rate of a chemical reaction depends on the frequency of effective collisions between reactant particles. When the temperature of a reaction is increased, the following occurs:

• Increased Kinetic Energy: The particles gain kinetic energy and move faster. This increased movement leads to a higher frequency of collisions between the reacting molecules.
• More Effective Collisions: With increased temperature, not only do collisions become more frequent, but a greater proportion of these collisions also have enough energy to overcome the activation energy barrier. This means that more collisions are effective in breaking bonds and forming new products.
• Higher Energy Collisions: The energy of the collisions increases, which can result in a higher likelihood of bond breaking, facilitating the conversion of reactants into products.

In summary, heating a reaction increases the kinetic energy of the particles, resulting in more frequent and more energetic collisions, thereby increasing the reaction rate.

2. Conclusions About the Depicted Haber Process at Different Temperatures (Assuming General Trends)

While I do not have access to the specific graph you mentioned on page 3, I can provide general conclusions typically associated with the Haber process at different temperatures:

• Temperature Effects on Yield: Generally, the Haber process for synthesizing ammonia (NH₃) from nitrogen (N₂) and hydrogen (H₂) is exothermic. According to Le Chatelier's Principle, increasing the temperature shifts the equilibrium position to favor the endothermic direction (the formation of reactants in this case), resulting in a lower yield of ammonia.
• Rate of Reaction: Higher temperatures increase the rate of the reaction, allowing it to reach equilibrium faster. Therefore, although the yield at high temperatures may be lower, the time needed to achieve equilibrium decreases.
• Optimal Temperature Range: A balance is often sought in industrial applications, where a moderate increase in temperature may enhance the reaction rate without significantly compromising the yield. For the Haber process, temperatures between 400°C and 650°C are typically used to optimize both yield and reaction time.

In conclusion, while higher temperatures can help to speed up the reaction, they may also reduce the yield of ammonia due to the equilibrium shift, necessitating a careful selection of operational conditions in the Haber process.