GIZMOs - Collision Theory - Answer key 2021 Complete Solution. Latest 2023/2024 A+ Score (Actual Exam)

Name: ___Vivek Shanavas___________________________________ Date:

_____1/25/2020___________________

Student Exploration: Collision Theory

Vocabulary: activated complex, catalyst, chemical reaction, concentration, enzyme, half-life,

molecule, product, reactant, surface area

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

1. Suppose you added a spoonful of sugar to hot water and another to ice-cold water. Which

type of water will cause the sugar to dissolve more quickly? _________________________

2. Suppose you held a lighted match to a solid hunk of wood and another match to a pile of

wood shavings. Which form of wood will catch fire more easily? ______________________

Gizmo Warm-up

A chemical reaction causes the chemical compositions of

substances to change. Reactants are substances that enter

into a reaction, and products are substances produced by

the reaction. The Collision Theory Gizmo allows you to

experiment with several factors that affect the rate at

which reactants are transformed into products in a

chemical reaction.

You will need blue, green, and orange markers or colored

pencils for the first part of this activity.

1. Look at the key at the bottom of the SIMULATION pane. In the space below, draw the two

reactants and two products of this chemical reaction.

Reactants: Products:

2. Click Play ( ). What do you see?

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A.

B.

The hot water

The shavings

A.

B.

 Reactant A bounces around bumping into

Reactant B which is on the right side vibrating against the side. When Reactant

A succeeds in breaking the bonds of Reactant B the orange substance on

Reactant B breaks off and bonds with Reactant A forming Product B, leaving the

two green substance molecules which are Product A

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Activity A:

Temperature

Get the Gizmo ready:

 Click Reset ( ).

 Check that the Reactant concentration is set to 1.0

mol/L, the Catalyst concentration is set to 0.00

mol/L, and the Surface area is Minimum.

Question: How does temperature affect the rate of a chemical reaction?

1. Observe: Select the ANIMATION tab. View the animation with No catalyst selected.

What do you see? __________________________________________________________

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When two reactant molecules meet, they form a temporary structure called an activated

complex. The activated complex breaks up into the product molecules.

2. Observe: Return to the CONTROLS pane. Set the Temperature to 0 °C and the Simulation

speed to its maximum setting. Click Play.

A. Describe the motions of the molecules. ____________________________________

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B. Now set the Temperature to 200 °C. How does increasing the temperature affect the

motions of the molecules? ___________________________________________

C. What do you notice about the chemical reaction at the higher temperature? _______

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 Reactant A speeds up, this also

speeds the breaking up of the reactant molecules and

formation of the product molecules.

 Reactant A

molecules are bouncing around with randomly and

quickly but some slow down for some reason

temporarily and Reactant B is clinging to the side

vibrating waiting for Reactant A to bump into it.

 I see Reactants A and B meet in the middle, the

bonds then break, then bonds form between the two blue

atoms and one orange atom, leaving the tw0 green atoms to

bond with each other, forming Products A and B.

 The

higher temperature sped up the reaction time.

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3. Interpret: Select the GRAPH tab. Click the zoom out button (–) until you can see the whole

graph. What does this graph show? ____________________________________________

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4. Predict: How do you think temperature will affect the rate of a chemical reaction? ________

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(Activity A continued on next page)

A increase in temperature means an increase in heat energy

being applied to the reaction. More energy will speed up the

reaction.

The concentration Of the reactants drop about .6 mol/L. the

tapers and holds steady till about 175 min mark then drops

an additional .2 mol/L. At each drop in the reactants the

concentration of the product rises the same amount.

 Nothing happens for the first 50 to 60 min of the reaction.

Then around 60 min mark the concentration of the reactants drops about .1 mol/L

and the concentration of the Product rise the same amount. A greater number of

bonds broke and a greater number of bonds formed around the 150 min to 160 min

mark.

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Activity A (continued from previous page)

5. Gather data: Click Reset. A useful way to compare reaction rates is to record the time

required for half of the reactants to react, called the half-life of the reaction. With the

Temperature set to 200 °C, click Play. Click Pause ( ) when the number of reactant

molecules is 10. Record the half-life time in the first space of the table below.

Trial 200 °C 150 °C 100 °C 50 °C

1 6:04 12:51 20:44 109:32

2 4:49 8:01 14:49 79:56

Mean half-life 5.27 10.26 17.47 94.44

Repeat the experiment at different temperatures to complete the table. (Note: To get exact

times, you can refer to the TABLE tab.)

6. Calculate: Calculate the mean half-life for each temperature. Fill in these values above.

(Hint: To get an exact mean, first convert each time to seconds by multiplying the minutes

value by 60 and adding this to the seconds. To find the mean in seconds, add up the two times

and divide by two. Convert the answer back to minutes and seconds.)

7. Analyze: What do your results indicate? _________________________________________

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8. Draw conclusions: For two molecules to react, they must collide at just the right angle and

with enough energy to break the original bonds and form new ones. Based on these facts,

why does the reaction tend to go more quickly at higher temperatures?

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9. Apply: Paper must be heated to 234 °C to begin reacting with oxygen. This can be done by

putting the paper over a flame. Why do you think the paper must be heated to start burning?

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 First of all, the speed

of the reaction varies at the same temperature. Also, the

speed of the reaction slows as the temperature lowers.

Because enough energy has to be added to the paper to

raise the temp of the paper to the point the paper bonds

begin to break causing the paper to change its phase