Final Exam

Question 0

Define exothermic vs. endothermic :

Answer 0

Exothermic- releases heat

Endothermic- requires heat

Question 1

Define rate reaction:

Answer 1

The rate at which products are produced. Expressed as unit/time.

Question 2

What is the collision theory ?

Answer 2

The idea that particles must physically collide in order for a chemical reaction to occur.

Question 3

What does a catalyst do in a chemical reaction? A inhibitor?

Answer 3

Catalyst- speeds up the reaction by reducing the amount of activation energy required
Inhibitor- slows down a chemical reaction

Question 4

What is a reaction mechanism?

Answer 4

A specific series of steps to illustrate exactly how a chemical reaction will work

Question 5

How can particle size affect the rate of reaction?

Answer 5

If particles are smaller they collide more and can move around more resulting in frequent collision making the reaction happen faster

Question 6

How does temperature affect the reaction rate?

Answer 6

Higher the temperature , the faster the reaction

Lower the temperature , slower the reaction

Question 7

How does the container size affect the rate of reaction?

Answer 7

Smaller the container, the more collisions speeding up the reaction
Bigger the container, the less amount of reactions slowing down the reaction

Question 8

Define equilibrium in a chemical reaction:

Answer 8

When the forward and reverse reaction rates are equal

Question 9

What is the law of equilibrium?

Answer 9

For every chemical reaction at equilibrium, there exists a ration between the products and reactants that will be a constant value at a given temperature.

Question 10

How does the value of an equilibrium constant show whether the reaction favours the products or reactants?

Answer 10

The larger the value, the more products
Keq>1 favours the products
Keq< 1 favours reactants

Question 11

Which states of matter are excluded from an equilibrium constant expression?

Answer 11

Solids and liquids

Question 12

What is LeChatelier’s principle?

Answer 12

States that if a stress is placed on a system it will shifts to offset the stress

Question 13

Define the Arrhenius theory of acids and bases?

Answer 13

All acids must contain H and all bases must contain OH-

Question 14

State the bronsted-Lowry theory of acids and bases?

Answer 14

All acids donate H and all bases accept H.

Question 15

List 5 strong acids.

Answer 15

HCL
H2SO4
HNO4
HI
HBr

Question 16

List 5 string bases.

Answer 16

NaOH
LiOH
KO
Ca(OH)2 
Ba(OH)2

Question 17

Give the 3 pH scale “rules” in terms of acid,base and neutral?

Answer 17

PH 7 base

PH=7 neutral

Question 18

Distinguish in terms of number of ions dissociated, the difference between a strong and weak acid or base.

Answer 18

Strong acids and bases are 100% dissociated which means the whole compound dissociates into positive and negative ions. Weak ones on the other hand remain as molecules with very few ions dissociating.

Question 19

Define polypropylene acid:

Answer 19

How many hydrogens are available to be ionized. They will only ionize at one time.

Question 20

Define mono, di and triprotic:

Answer 20

Mono- has 1 H
Di- has 2H
Tri- has 3 H

Question 21

What is the KW expression for self ionization for water?

Answer 21

H2O + H2O ——-> H + OH-

Question 22

What does it mean in terms of Kw for a solution to have a pH of 7?

Answer 22

It means that H3O = OH- in the solution

Question 23

Define oxidation and reduction:

Answer 23

Oxidation - loss of electrons

Reduction- gain of electrons

Question 24

What is the function of an anode and cathode?

Answer 24

Anode- site of oxidation

Cathode site of reduction

Question 25

What is the function of the salt bridge ?

Answer 25

Io ice solutions fills the tube which allows the positive and negative ions to pass through to keep the cell overall neutral.

Question 26

What is meant by the ground state of an element ?

Answer 26

This is the location of all electrons in an element at its most minimum energy state

Question 27

What are the 4 orbital shapes called ? What are the general shapes of them ?

Answer 27

S- circular
P- dumbbell
D- flower shapes
F- varying shapes

Question 28

How many electrons can each orbital hold?

Answer 28

2 electrons per lobe

Question 29

Name and describe the three rules that determine how electrons will be arranged in orbitals.

Answer 29

Hunds principle- each orbital in a shell must contain one electron before a second electron will fill any lobe
Pauli exclusion principle- each lobe of an orbital can hold up to two electrons
Aufbau principle - electrons will be added to the orbitals beginning at the lowest available energy

Question 30

Define principle quantum number:

Answer 30

The principle quantum number of an element describes the size of the orbit of that particular element

Question 31

Define ionization energy:

Answer 31

The amount of energy it takes to remove an electron from the valence she’ll of an electron

Question 32

Describe the trend in atomic radii on the periodic table.

Answer 32

The size of an atom gets smaller as you go from left to right across a period (row). This is due to more concentration nucleus holding on to electrons while the outer most orbit doesn’t actually get a whole lot larger. It gets larger as you go down a group (column). This is because there are more orbitals and they are just physically larger