Potential Energy & Kinetic energy
What is the definition of Potential Energy (Gravitational Potential Energy)?
The energy stored in an object due to its position above the Earth's surface.
What are bonds?
A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds.
What is activation energy?
The minimum amount of energy that must be provided for compounds to result in a chemical reaction.
A negative value for enthalpy is exo- or endothermic?
Exothermic, energy is released.
What causes molecules to collide?
Kinetic energy
Strong bonds need a lot of what to break them?
Weak bonds don't need as much of what to break them?
Kinetic Energy
What is enthalpy?
The total change in energy in a chemical reaction.
An exothermic reaction causes the temperature to do what?
Go up.
Why do scientists use PE diagrams?
To see how energy changes over time in a chemical reaction.
In a exothermic reaction what kind of bonds form and what kind break?
Weak bonds break, strong bonds form.
On the a potential energy diagram where would you find the activation energy?
Between the reactants and the transition state at the top of the curve.
Give an example of an endothermic and exothermic reaction.
Exothermic-hot pack
Endothermic-salt dissolving in water
When potential energy increases the enthalpy is positive or negative?
Strong bonds formed has more or less PE than weak bonds being broken?
Less PE
How do we calculate enthalpy?
Enthalpy= (Bond Energies in Reactants)-(Bond Energies in Products)
What evidence would we need to collect in a lab to see if a reaction is exothermic or endothermic?
Temperature
When PE increases what happens to KE. Give a relationship.
As PE increases KE decreases.
As KE increases PE decreases.
What pattern did we see when we looked at bonds and their energies (single, double, triple).
Double and triple bonds have more energy then single bonds.
What happens to the total amount of energy of the system and surroundings when a reaction takes place?
Relate KE, PE, temperature, energy to an exo- and endothermic reaction.
In exothermic KE goes up, temp goes up, energy is released, PE goes down.
In endothermic KE goes down, temp goes down, energy is absorbed, PE goes down.