HChem Chemical Kinetics Test Flashcards Preview

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Flashcards in HChem Chemical Kinetics Test Deck (36)
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1
Q

The enthalpy change is the _____ of the reaction and is found by ____________

A

Heat

Products-reactants

2
Q

The activation energy=

A

Activated complex-reactants

3
Q

Enthalpy changed and activation energy have what unit?

A

In

4
Q

The strongest bonds are where the _____ energy is greatest

A

Kinetic (potential energy is weakest)

5
Q

The weakest bonds are where the ____ energy is strongest

A

Potential (kinetic is weakest)

6
Q

Why are bonds with greater potential energy weaker

A

They are closer to the activated complex and it takes less force to break the bonds

7
Q

As reactant molecules approach each other, they exert ________ forces on each other. Thus, as they move together, their speed ___________ and their potential energy __________

A

Repulsive, goes down, goes up

8
Q

What is the activated complex

A

The intermediate created at the peak of the reaction

9
Q

What is the activation energy

A

The energy required to break the bonds/ minimum quantity of energy that the reacting species must possess in order to undergo a reaction

10
Q

What two requirements must be met before a collision between two reactant particles is effective

A

Must collide with high energy (greater of equal than Ea)

Must hit each other with the correct orientation

11
Q

A slow reaction would start with a ______ PE

A

High

12
Q

The activated complex of a step is represented by the ____ while the intermediate is represented by the __________

A

Peak, valley at the bottom

13
Q

Would you expect a reaction with 5 particles to take place in one step

A

No- they won’t collide at the right speed and orientation the first try

14
Q

Adding a catalyst to any step but the RDS will/will not affect the reaction rate

A

Will not

15
Q

If a catalyst is discovered that increases the rate of the RDS, how will the overall reaction be affected

A

It will increase

16
Q

The RDS has the _____ peak

A

Highest

17
Q

The sum of your elementary step will equal the ______ reaction

A

Overall

18
Q

How do you know which of two fast steps will be faster

A

Check for intermediates

19
Q

A catalyzed reaction will ____ at the same place but have a smaller ___________

A

Begin, activation energy (shorter peak)

20
Q

Doubling the concentration of ClO- quadruples the initial rate of formation of ClO3-
How would you write the rate expression

A

2^x=4
X=4
R=k[ClO-]^2

21
Q

Be sure to check the ______ in scientific notation to make sure it is negative/positive

A

Exponent

22
Q

Check the unit in the box for __________ to know what it should be in the answer

A

Reaction rate (usually M/s)

23
Q

If volume decreases, equilibrium will shift towards the side with _____ moles

A

Less

24
Q

Intermediates may not appear in _________, but sometimes they have a substitute in the mechanism

A

Reaction rates

25
Q

Catalysts are __________ in an early step in the mechanism an a ________ in a later step

A

Reactant, product

26
Q

Increasing the volume of system will shift the equilibrium towards the side with _____ moles of gas

A

More

27
Q

Decreasing the volume of a system will shift the equilibrium to the side with _______ moles of gas

A

Less

28
Q

When is a reaction at equilibrium

A

Rate of formation on one side=one of formation on the other

29
Q

If forward direction was favored, you use more ________ and form more ________

A

Reactants, products

30
Q

Anything that doesn’t affect the rate is _________ order

A

0

31
Q

______________- decomposition reaction (order of reactant is 1)
______________- second order overall in reactants
______________- 3 or more reactants, overall order is 3

A

Unimolecular
Bimolecular
Termolecular

32
Q

Catalyst, temperature, surface area, concentration all affect _________

A

Collisions

33
Q

Your unit for k is M ^-___ s^-1

A

Overall order minus 1

34
Q

Intermediates are ________ in early steps and ________ in later steps

A

Product, reactant

35
Q

if concentration vs time is a straight line,

If concentration vs 1/time is a straight line,

A

Zero order Rxn

First order Rxn

36
Q

An ______ gains heat while an ________ loses heat

A

Endothermic, exothermic