Reaction Rates, Factors Affecting Reaction Rates, and Collision Theory

Question

Use the equation to answer the questions. C6H12O6 (s) + 6 O2(g) → 6 H2O (g) + 6 CO2 (g)

1. What happens to the concentrations of:

a. C6H12O6 and O2 as the reaction proceeds →?

b. H2O + CO2 as the reaction proceeds →?

2. According to the collision theory, what 3 circumstances are needed for C6H12O6 & O2 to react?

Complete the table below.

(I can't put the table, sorry, it has 3 columns & 10 rows)

1st column

Change in condition:

a. Increasing the temperature

b. Increasing the concentration of C6H12O6

c. Decreasing the concentration of O2

d. Increase the surface area by chewing up food in your mouth

e. Decreasing the temperature

f. Increasing the pressure in the container

g. Decreasing the concentration of H2O

h. Increasing the volume of the container the reaction occurs in

i. Increasing the concentration of CO2

j. Using a catalyst (like salivary amylase)

2nd column

Does this increase or decrease the rate of reaction?

Ex: Increases (speeds up)

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3rd column

Explain why using Collision Theory.

Ex: Molecules move faster & collide more = Increased reaction rate

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Answer 1

Peach,

On the left you have the reactants and on the right, there are products. As the reaction proceeds, with the arrow indicating the direction of the reaction, the idea is to have the reactants converted to products since it's going in a forward direction. As the reaction goes, reactants concentrations should be decreasing and products concentration increasing as one gets converted to the other.

With respect to collision theory, the 3 main things required simultaneously are:

---- proper orientation

---- effective collisions

----- activation energy

Factors that increase a reaction rate are:

--- increase in reactant concentration (more particles, so more collisions likely)

---- increase in temperature (increase in kinetic energy so molecules move faster increasing chances of collisions, also may be more likely to have the required activation energy)

---- increase in surface area (more area for reaction to take place, increases chances of collisions)

---- using a catalyst (lowers activation energy providing an alternate pathway for the reaction to proceed)

Decreasing any of the above can cause a decrease in the reaction rate.

Increase in pressure (which is the same as a decrease in volume) depends on the number of moles of gases involved in the reaction. If it's a reversible reaction, increasing the pressure will cause the reaction to shift to the side that has fewer gas molecules. Decreasing the pressure (which is the same as increasing the volume) will have the opposite effect.

Hope this helps.