Chemical Reactions
What are chemical reactions?
Chemicals that react to change.
The "chemicals" in a chemical reaction are elements or compounds. They "react" when combined or broken down.
What type of chemical reaction is this?
H2 + O2 --> H2O
Synthesis Reaction
What is an exothermic reaction?
What happens to energy and temperature?
Exothermic reactions are reactions in which energy is given out to the surroundings, increasing the energy of the surroundings so they have more energy than they started with. There is a temperature increase.
What is activation energy?
a stimulus that is needed for the reaction to occur (initial energy)
Think of a roller Coaster!
This helps get everything started.
How does surface area affect reaction rate?
more space, more contact, more collisions
increased surface area, increased reaction rate
Is this a chemical formula or a chemical equation?
2H2O
chemical formula
What type of chemical reaction is this?
H2O2 --> H2O + O2
Decomposition Reaction
What is an endothermic reaction?
What happens to energy and temperature?
Endothermic reactions are reactions in which energy is taken in during the reaction, meaning that the surroundings have less energy than they started with. There is a decrease in temperature.
Describe equilibrium due to forces
Cancels each other out.
Ex. Seesaw-equal weight on each side.
(BALANCED)
How does stirring affect reaction rate?
moving the reactants around means more contact
increased stirring, increased reaction rate
What is the difference between reactants and products in a chemical equation?
reactants are what you start with, on the left side of the arrow.
products are what you end with, on the right side of the arrow.
What type of chemical reaction is this?
Zn + CuSO4 --> ZnSO4 +Cu
Single-Replacement Reaction
Would this be an exothermic reaction or an endothermic reaction?
Combustion Reaction
Exothermic Reaction
Describe physical equilibrium and give an example of a physical change
No chemical change has taken place.
Ex. Cutting paper
How does temperature affect reaction rate?
increase in temperature will make particles move faster. (more reactions)
increased temperature, increased reaction rate
What is the Law of Conservation Mass?
Atoms are neither created nor destroyed.
In a chemical reaction, the total mass of the substances before and after the reaction remains the same.
What type of chemical reaction is this?
NaCl + AgNO3 --> AgCl + NaNO3
Double-Replacement Reaction
Would this be an exothermic reaction or an endothermic reaction?
Electrolysis Reaction (Lab)
Endothermic Reaction
Describe chemical equilibrium
Rate of change happens at the same rate - changing and reversing.
The Ultimate state of stopping.
It will appear as though nothing has happened, but it did. Just very fast!
How does concentration affect reaction rate?
more particles=more reactions
increased concentration, increased reaction rate
The quantity of elements and their ______ remain the ________ before and after a chemical reaction.
atoms, same
What type of chemical reaction is this?
Br2 + 2NaI --> 2NaBr + I2
In a chemical reaction, the total amount of _________ in the universe at the ___________ of a reaction, is the __________ as it was at the ___________ reaction. Energy is ______________. When a chemical reaction occurs, energy is transferred either to or from the _______________.
energy, end, same, start, conserved, surroundings
What are the 3 requirements for The Collision Model?
How do catalysts affect reaction rate?
a substance that helps a reaction happen faster.
(We will see this in the elephant toothpaste lab)