What process releases energy?
Forming a bond
What process requires energy?
Breaking a bond
What is bond energy?
The strength of a bond
If the energy used to break bonds is greater than the energy released in the formation of new bonds, what type of reaction is this? What happens to the molecules in motion?
Type of reaction- Endothermic
Molecular motion slows down, resulting in a decrease in temperature.
If the energy used to break bonds is less than the energy released in the formation of new bonds, what type of reaction is this? What happens to the molecules in motion?
Type of reaction- Exothermic
Molecular motion speeds up, resulting in an increase in temperature.
What happens to the temperature of water when weak bonds are broken? When strong bonds are broken?
When weak bonds break, minimum energy is absorbed resulting in a slight decrease in temperature
When strong bonds break, maximum energy is absorbed resulting in a large decrease in temperature
What are the 4 types of bonds? Which one is the most stable and why?
Single, double, triple, ionic.
Ionic is the most stable because it's the strongest bond
Define endothermic in terms of system, surroundings, and heat.
In endothermic reaction, the system absorbs energy to the surroundings resulting in a negative heat transfer.
Define exothermic in terms of system, surroundings, and heat.
In exothermic reaction, the system releases energy to the surroundings resulting in a positive heat transfer.
What are some properties of alkali metals? What gas was produced when alkali metals were added to water? What type of reaction was this?
It reacts with water and oxygen and makes hydroxide.
Hydrogen
Exothermic
Give evidence to why/ why not do magnets/ particles need a force for them to come back together
In lesson 9, if particle B didn't absorb enough energy, it would return to magnet 1
Give evidence to why/ why not magnets/ particles have positive and negative ends that attract poles.
We "played" with them in lesson 5
Give evidence to why/ why not magnets/ particles are attracted to each other no matter what is distance is.
During lesson 9, the particle B left the "force" and didn't come back to the magnet
Give evidence to why/ why not magnets/ particles need energy to move against the direction of a focus (to break them apart).
Lesson 5 and 9
When water collides with substances and break their bonds; what happens to the water? How do we know?
Water loses its kinetic energy
We know because the temperature dropped
What does the diagram of the 2 marbles on a ramp represent and why?
The 1st marble represents water and the 2nd marble represents KCI
The 2nd marble is held in place by the magnet, so its bond must break and only marble 1 can break the bond.
What is the relationship between strong bonds and temperature?
The stronger the bond, the larger the temperature drop.
Why did the board freeze to the beaker in lesson 1?
More energy was needed to break the bonds then was released when the new bonds formed
Where is the energy coming from to break the bonds of KCI?
From the kinetic energy of the water
Where did the energy from barium hydroxide and ammonium chloride come from to break the bonds and cause a temperature drop?
From the water that was created.
What is temperature?
The measurement of the average KE molecules
What is heat?
The flow of energy from high to low concentration
What would be the best way to raise the temperature of the water in a small pool?
Use a big bucket of hot water because it contains a large amount of the thermal energy
What is thermal energy? What happens to molecules if thermal energy is increases?
Internal molecular motion
More thermal energy = faster molecules