Chapter 5B - Chemical Reactions Flashcards
What is a chemical change?
A change in matter where new substances are produced.
What is a physical change?
A change in matter where no new substances are produced.
What scientific law requires that we balance chemical equations?
The Law of Conservation of Matter
What is stated in the Law of Conservation of Matter?
Matter cannot be created nor destroyed.
What is an endothermic reaction?
Reaction where energy Is absorbed or added.
What is an exothermic reaction?
Reaction where energy is released or removed.
What is activation energy (Ea)?
Minimum amount of energy for a reaction to occur on its own.
What is Delta H?
The total energy change during a reaction.
The Delta H arrow on a heating/cooling curve always goes from…
The start to end line.
The Activation Energy arrow on a heating/cooling curve always goes from…
The start line to the top line (above end line).
How does temperature affect the rate of a chemical reaction?
The particles’ speeds increase as the temperature increases. This leads to a faster reaction. Also, the particles’ speeds decrease as the temperature decreases. This leads to a slower reaction.
How does concentration affect the rate of a chemical reaction?
A higher concentration means more collisions and more collisions means a faster reaction. A lower concentration means less collisions and less collisions means a slower reaction.
How does particle size affect the rate of a chemical reaction?
The larger the particles are, will result in a slower reaction. The smaller the particles are, will result in a faster reaction.
What is the purpose of a catalyst?
To speed up a chemical reaction
How is a catalyst different from a reactant?
A catalyst isn’t part of a reaction. However, a reactant disappears in a reaction. Therefore, a catalyst is reusable, whereas a reactant can only be used once.
