Unit 1

Question 1

Reaction Rate Formula?

Answer 1

Difference in amount/Difference in Time

Question 2

Which properties can be monitored to discover the reaction rate?

Answer 2

Colour change, temperature change, pressure change, mass change, change in pH.

Question 3

How do you measure colour?

Answer 3

Spectrophoto meter

Question 4

How do you measure Temperature change?

Answer 4

A thermometer to measure temperature.

Question 5

Line of best fit? Otherwise known as?

Answer 5

Line that goes through atleast two points of reference. A tangent line.

Question 6

Why is pressure NOT a good property to monitor this equation: H2(g) + Cl2(g) -> 2HCl (g)?

Answer 6

2 mol of gas used per 2 mol of gas produced therefor not pressure changes occur

Question 7

What are 6 factors that affect reaction rates?

Answer 7

Temperature, concentration, pressure, ability for reactants to meet; surface area and phase considerations, nature of reactants, catalysts

Question 8

What effect does temperature have on reaction rates?

Answer 8

Increasing temperature increases the reaction rate.

Question 9

Why does temperature increase the reaction rate?

Answer 9

have more kinetic energy (move faster) so they collide more often and have sufficient energy to react.

Question 10

What effect does pressure have on reaction rates?

Answer 10

As the volume decreases, the pressure increases, therefor the reaction rate increases

Question 11

Why does pressure increase the reaction rate?

Answer 11

The molecules are closer together giving more opportunity for a reaction.

Question 12

What effect does concentration have on the reaction rate?

Answer 12

higher concentration of reactant particles increases the reaction rate.

Question 13

Why does concentration of reactant particles increase the reaction rate

Answer 13

reactant particles have a higher probability of reactions w/ eachother rather than the solvents

Question 14

What effect does the ability for reactants to meet have on the reaction rate?

Answer 14

The greater the surface area, the greater the reaction rate. liquid reactants react faster than solid reactions.

Question 15

why does the ability for reactants to meet increase the reaction rate?

Answer 15

more surface area means more available locations for reactants to meet. gas & liquids move more freely w/ eachother. dissolved ions have the benefit of strong positive-negative attractions.

Question 16

what effect does the nature of the reactants have on the reaction rate?

Answer 16

when bonds are weak and electrons are easily shared, reactions occur more quickly.

Question 17

Why does the nature of the reactants increase the reaction rate?

Answer 17

Some reactions are faster because the bonds being broken are weak and electrons are easily shared.

Question 18

What effect do catalysts have an the reaction rate?

Answer 18

they are a chemical which increase the reaction rate while not being consumed in the overall reaction.

Question 19

why do catalysts increase the reaction rate?

Answer 19

it speeds things up by offering an alternative reaction mechanisms w/ a lower activation energy.

Question 20

What is the difference between a heterogeneous and homogeneous reaction?

Answer 20

heterogeneous: reactions where the reactants are in different phases ex. gas/liquid
Homogeneous: reactions where the reactants are in the same phase ex. Gas/gas.

Question 21

define a catalyst

Answer 21

A chemical which increases the rate of the reaction while not being consumed.

Question 22

What is one factor that affects only the rate of heterogeneous reactions. Why does it not affect homogeneous reaction rates?

Answer 22

Surface area; there is no concept of surface area when a mixture is homogeneous

Question 23

Define Kinetic Energy

Answer 23

the energy of motion. anything that is moving has kinetic energy

Question 24

What is the importance of the Kinetic Molecular Theory (KMT)?

Answer 24

The only theory available that accurately predicts macroscopic properties of gas like temperature, pressure and thermal expansion by considering their molecular composition and motion.

Question 25

KMT relies on the following assumptions:

Answer 25

• size of particles not significant compared to the space between them.
• molecules are in constant motion
• constantly collide and have the same kinetic energy before and after collision
• except during collision, the particles dont exert any attractive or repulsive forces

Question 26

Based on collision theory, how do molecular reactions occur?

Answer 26

chemical reactions being products of molecular collisions.

Question 27

What are the two main points of collision theory?

Answer 27

• for any reaction to occue, the reactants must collide w/ enough energy and correct orientation.
• the reaction rate depends on the frequency of collisions.

Question 28

What happens to the portion of molecules on a Kinetic Energy Distribution Diagram that react as you increase the temperature?

Answer 28

Shifts KE distribution to the right so that more particles have energy greater than or equal to the activation energy requirement.

Question 29

What happens to the shape of the KE distribution curve if the reactant is used up at a constant temperature?

Answer 29

smaller curve, but peak still have the same KE value.

Question 30

What happens to the shape of the KE distribution curve if the temperature is decreased?

Answer 30

The peak is at a lower KE & higher than initial

Question 31

What happens to the shape of the KE distribution curve if the concentration of reactants is increased?

Answer 31

more moleculed w/ the same kinetic energy.

Question 32

Define Kinetic Energy

Answer 32

The energy of motion. Anything that is moving has KE.

Question 33

Define Potential Energy (PE)

Answer 33

The energy that has the potential to do something. In other words: it has the potential to be converted into other forms of energy. They have PE due to their attractive & repulsive forces.

Question 34

How is PE & KE related according to the law of conservation of energy?

Answer 34

In an isolated system, such as a chemical reaction, KE is transformed into PE and vise versa, but the total amount of energy stays the same.

Question 35

Before atoms/molecules react, they have high ___ and low ___.

Answer 35

Before atoms/molecules react, they have high KE & Low PE.

Question 36

As molecule approach eachother, the outer electrons start to ____ eachother. Thus ____ ____ the molecules and converting ___ into ____. ___lost = ___gained.

Answer 36

As molecules approach each other, the outer elections start to repel eachother, thus slowing down the molecules and converting KE into PE. KE lost = PE gained.