C6 - The Rate Of Chemical Changes Flashcards
(21 cards)
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What is the rate of a chemical reaction?
How fast reactants are turned into products.
How can the rate of reaction be measured?
By measuring the amount of reactant used or product formed over time.
What is the formula for rate of reaction?
Rate = Amount of reactant used or product formed / Time
What units are used for rate of reaction?
g/s or cm³/s or mol/s
What does a steep line on a rate graph show?
A fast reaction.
What happens to the line on a rate graph when the reaction stops?
It levels off (becomes horizontal).
Name four factors that affect the rate of a reaction.
Temperature, concentration (or pressure), surface area, and presence of a catalyst.
How does increasing temperature affect the rate?
It increases the rate because particles move faster and collide more often and with more energy.
How does increasing concentration or pressure affect the rate?
It increases the rate because particles are more crowded and collide more often.
How does increasing surface area affect the rate?
It increases the rate because more particles are exposed for collisions.
What is a catalyst?
A substance that speeds up a reaction without being used up.
How do catalysts work?
They lower the activation energy needed for the reaction.
What is a reversible reaction?
A reaction where the products can react to form the original reactants.
What is dynamic equilibrium?
When the forward and reverse reactions occur at the same rate in a closed system.
What is meant by a closed system?
No substances can enter or leave.
What is Le Chatelier’s Principle?
If conditions change, the system will counteract the change to restore equilibrium.
If temperature is increased, which direction does equilibrium shift?
To the endothermic direction.
If pressure is increased, which direction does equilibrium shift?
To the side with fewer gas molecules.
If concentration of a reactant is increased, what happens?
The system shifts to make more products.
What is the effect of a catalyst on equilibrium position?
It doesn’t affect the position, but helps equilibrium reach faster.
