Realize the factors of a collision which vary the reaction. Be able to draw a picture of the two types of collisions that do not produce a reaction and the type of collision that does.
Background Summary:
You should know that molecular compounds are two or more molecules bonded together to make a new molecule. For example, H2 + O2 -> H2O.
The variables that affect collisions are temperature, orientation, and concentration of molecules. Temperature is the average kinetic energy of atoms or molecules in a substance. Kinetic energy is how much energy a substance has after it is in motion. If the kinetic energy is high, then the temperature is high and if the kinetic energy is low, the temperature is low.
http://tannerm.com/temperature.htm
Orientation is how the molecules are formed in respect with one another. For example, molecule 1 could have orientation AB while molecule 2 could have orientation BA. It's the same molecule, just oriented differently.
Concentration is the amount of molecules of a substance in a certain volume. A highly concentrated substance would have many molecules in a small volume and a lowly concentrated substance would have very few molecules in a large volume.
Therefore, if there is high temperature which causes highly energized molecules, high concentration which allows more molecules to react with each other, and correct orientation which allows collisions to happen effectively, there would be many successful reactions taking place.
Lesson:
Below are flash animations showing 1 type of collision that leads to a successful reaction and 2 types of collisions that lead to unsuccessful reactions.
Question 1: Why don't collisions occur when molecules react in low temperatures?
a. The orientation of the molecules are wrong
b. The orientation of the molecules are correct
c. The molecules are moving too fast to be able to collide
d. The molecules are moving too slow to be able to collide
Correct Answer: d
a and b are wrong because the orientation of a molecule doesn't have to do with the temperature that it is in.
c is wrong because low temperatures create slow movement while fast temperature create faste movement because when it is hotter, energy increases.
Question 2: When the orientation of colliding molecules is wrong, what happens?
a. The molecules won't collide
b. The molecules will collide and new molecular compounds will be made
c. The collision will happen and the molecular compounds will break apart rather than combine to make new molecules
d. The molecules won't collide but a new molecule will be made
Correct Answer: a
b is wrong because when the orientation of colliding molecules are wrong, they cannot collide.
c is wrong because when the orientation is wrong, collisions won't happen. Molecular compounds also cannot break apart after colliding.
d is wrong because new molecules cannot be made when molecules don't collide.
Question 3: What are the factors that affect the occurrence of collisions?
a. Temperature and orientation
b. Concentration, orientation, and temperature
c. Energy and concentration
d. Orientation
Correct Answer: b
a is wrong because although temperature and orientation are factors, they are not all of them.
c is wrong because it is not technically energy that is a factor but rather temperature which is the average kinetic energy of atoms. This choice is missing a factor.
d is wrong because there is more than one factor to the collision model.
1.) The ineffective and effective orientations of colliding molecules,
2.) Slow and fast colliding molecules,
3.) How the different concentrations of molecules affects how many collisions will occur.
The molecules do not have to be detailed, they can just be represented by different colored circles. Include an explanation along with your drawing to explain in words what is going on. If it is too difficult to do a drawing of a certain topic, than write an explanation and include images from the internet.
Drawing any of the above orientations will be correct, however you should try to come up with different molecules because it will be easier to remember. Also, you could try and relate it to the real world by pretending that molecules are things like magnets, water and fire, and other similar things.
