Chem 112 Exam 2

Front 1

Define reaction rate

Back 1

rate of reaction, is a measure of how fast a reaction occurs

Front 2

What are the 4 conditions that affect the rate of reaction?

Back 2

temperature, reactant concentration, surface area, and the presence of a catalyst

Front 3

How does temperature affect the rate of the reaction?

Back 3

higher temperatures generally cause reactions to occur faster

Front 4

How does the concentration affect the rate of the reaction?

Back 4

Increasing the concentration of a reactant generally increases the reaction rate

Front 5

How does the surface area affect the rate of the reaction?

Back 5

Ifthe reactant is a solid, increasing its surface area also increases reaction rate.

Front 6

Explain how when a metal is in granular form, it affects the reaction rate.

Back 6

Metals in their granular form have greater surface area and react more quickly with air than large pieces of metal

Front 7

What does the collision theory state?

Back 7

states that in order for a reaction to occur, reactant molecules must collide in the proper orientation and with sufficient energy

Front 8

What is required for a collision to happen and form a product?

Back 8

Must have sufficient energy and must collide in the right place

Front 9

If two molecules collide with the proper orientation, will the reaction always occur? Why or Why not?

Back 9

No, the molecules must also have a sufficient amount of energy

Front 10

Why does the rate of chemical reactions vary so widely?

Back 10

Different reactions occur at different rates because the amount of energy required to break bonds in the reactant molecules is different

Front 11

What must reactants overcome before they can change to products?

Back 11

Reactants must overcome an energy barrier before they can change

Front 12

What is the activation energy?

Back 12

The minimum amount of energy needed to overcome this energy barrier

Front 13

The (lower/higher) the activation energy the faster the reaction/

Back 13

lower

Front 14

Reactant molecules that collide with the proper orientation and sufficient energy form what?

Back 14

An activated complex

Front 15

What is an activated complex?

Back 15

a short-lived, unstable, high-energy chemical species that must be achieved before products can form

Front 16

How can you tell what the activated complex is?

Back 16

Designated by a chemical formula in brackets with a superscript double dagger

Front 17

Which is faster, a reaction with large activation energies or a reaction with small activation energies

Back 17

Reactions with large activation energies tend to be slow and reactions with small activation energies tend to be fast

Front 18

What 3 conditions most oft4n affect reaction rates?

Back 18

Changes in concentration, surface area, and temperature

Front 19

How does the concentration affect the rat of the reaction?

Back 19

A reaction may go faster when the concentration of one or more of the reactants increases

Front 20

How does the surface area affect the rate of the reaction?

Back 20

Increasing the surface area increases the number of atoms that are exposed so that they can collide with other reactions

Front 21

Why does the reaction proceed more rapidly at higher temps?

Back 21

Because when the temperature inc., the kinetic energy inc., which causes more collisions, which causes the reaction rate to inc.

Front 22

How does the increase in kinetic energy cause the reaction rate to increase?

Back 22

(1) increases the collision rate (2) increases the fraction of collisions that are effective

Front 23

What is a catalyst?

Back 23

something that alters the pathway in which a reaction occurs without itself being consumed in the reaction

Front 24

How does a catalyst increase the rate of a reaction?

Back 24

With lower activation energy, a greater fraction of reactants can achieve the new minimum energy requirement, and the reaction rate increases. The new reaction pathway is a lower-energy pathway with lower activation energy.

Front 25

Define enzyme

Back 25

a molecule that catalyzes specific reactions within living organisms

Front 26

What do enzymes do?

Back 26

catalyze all the processes necessary for the proper functioning of the human body

Front 27

What are active sites and substrates and how do they correspond?

Back 27

a depression or hole that is unique to an enzyme and allows it to interact with only one specific kind of reactant molecule (substrate)

Front 28

What is shown in the net equation?

Back 28

only the reactants and products

Front 29

Define chemical equilibrium

Back 29

a state reached by a chemical reaction where there is no change in the concentrations of reactants and products

Front 30

When is chemical equilibrium established?

Back 30

When a single reaction occurs in which reactants are converted to products, and these products are converted back to reactants by the reverse process at an equal rate

Front 31

What happens once a reaction reaches equilibrium?

Back 31

The forward reaction continues to occur, but the reverse reaction also occurs at the same rate

Front 32

How do you represent a state of equilibrium>

Back 32

represented by using an equilibrium arrow (arrow pointing both direction, half arrow)