8. The Rate and Extent of Chemical Change Flashcards
How can the rate of a chemical reaction be found?
By measuring the amount of a reactant used or the amount of product formed over time:
Rate of reaction =
amount of reactant used / time
Rate of reaction =
amount of product formed / time
What must occur for a chemical reaction to happen?
Reacting particles must collide with each other and with sufficient energy (activation energy).
How does temperature affect the rate of reaction?
Increasing temperature increases the speed and energy of reacting particles, leading to more frequent and energetic collisions, thus increasing the rate of reaction.
How does pressure affect the rate of reaction in gases?
Increasing the pressure of reacting gases increases the frequency of collisions and thus increases the rate of reaction.
How does concentration affect the rate of reaction?
Increasing the concentration of reactants in solutions increases the frequency of collisions and thus increases the rate of reaction.
How does surface area affect the rate of reaction?
Increasing the surface area of solid reactants increases the frequency of collisions and thus increases the rate of reaction.
What is the role of catalysts in chemical reactions?
Catalysts change the rate of chemical reactions but are not used up during the reaction. Different reactions need different catalysts.
Why are catalysts important in industrial processes?
Catalysts are important in increasing the rate of chemical reactions used in industrial processes to reduce costs.
What happens when a reversible reaction occurs in a closed system?
Equilibrium is reached when the reactions occur at exactly the same rate in each direction.
How does temperature affect the equilibrium position of a reaction?
If the temperature is raised:
- The yield from the endothermic
reaction increases.
- The yield from the exothermic
reaction decreases.
If the temperature is lowered:
- The yield from the endothermic
reaction decreases.
- The yield from the exothermic
reaction increases.
How does pressure affect the equilibrium position in gaseous reactions?
An increase in pressure favors the reaction that produces the least number of molecules.
A decrease in pressure favors the reaction that produces the greatest number of molecules.
Why are equilibrium factors and reaction rates important in industrial processes?
They are important for determining the optimum conditions in industrial processes, including the Haber process.
What are the raw materials for the Haber process?
Nitrogen (obtained from the air)
Hydrogen (obtained from natural gas or other sources).
Why is ammonia important?
Ammonia is a raw material in the production of fertilizers.
What conditions are used in the Haber process?
Catalyst of iron.
High temperature (about 450°C).
High pressure (about 200 atmospheres).
