Lecture 2

Question 1

What is an atom?

Answer 1

The smallest particle of an element. Comprised of an equal number of electrons and protons

Question 2

What charge do atoms have?

Answer 2

they are electronically neutral and have no charge

Question 3

What elements are stable as individual atoms?

Answer 3

Only noble gases, other individual atoms are not stable as individual atoms

Question 4

Atoms are comprised of an equal number of __ and __.

Answer 4

protons and electrons

Question 5

What are molecules?

Answer 5

Molecules consist of a group of similar or different atoms in such a structure that all electrons are paired with other electrons. They are either participating in a bond between atoms or they are cohabitating in an orbital on one of the atoms (such as Nitrogen)

Question 6

What do molecules consist of?

Answer 6

atoms that are electronically neutral and have no charge

Question 7

Give some examples of molecules.

Answer 7

O2, N2, CH4, CH3OH

Question 8

What are radicals similar to and why?

Answer 8

similar to molecules in that they are an assembly of atoms and they electronically neutral with no charge

Question 9

What are radicals?

Answer 9

One electron remains unpaired in a radical. They drive chemical reactions due to their instability and reactivity

Question 10

All atoms with the exception of ___ can be considered to be radicals.

Answer 10

noble gases

Question 11

Are radicals stable or not stable?

Answer 11

not stable and can not be easily isolated

Question 12

Give some examples of radicals?

Answer 12

H, CCl3, OH, CH3CH2

Question 13

What are Ions?

Answer 13

charged particles

Question 14

Ions have a different number of ___ than ____.

Answer 14

electrons than protons

Question 15

In the gas phase ions exist only at a much _____ than atoms and radicals.

Answer 15

higher energy

Question 16

In condensed ionic solutions such as aqueous salt solutions, ions exist in ____ at ______.

Answer 16

solution at room temperature

Question 17

Give examples of ions.

Answer 17

NH4+, Na+, OH-, Cl-

Question 18

What is a simple dissociation?

Answer 18

A single bond within a molecule breaks forming two radicals from a molecule

Question 19

Simple dissociations are often called the _____ in a chain reaction.

Answer 19

initiation step

Question 20

Give examples of simple dissociation.

Answer 20

H2-> 2H
CH3CL-> CH3+ Cl
RR’->R+R’

Question 21

What is molecular elimination?

Answer 21

A smaller stable molecule is ejected from a larger stable molecule.

Question 22

Give an example of molecular elimination.

Answer 22

C2H5F-> HF+C2H4

Question 23

What is a type of reaction that is considered a molecular elimination?

Answer 23

Reverse Diels- Alder
C6H10->C4H6 + C2H4

Question 24

What is abstraction?

Answer 24

A reaction between a radical and another species where the radical removes an atom from the other species becoming a molecule and typically creating a new radical in its place

Question 25

What is another word for abstraction?

Answer 25

continuation or branching

Question 26

Give an example of an abstraction.

Answer 26

CH3 + CCl4 -> CH3Cl + CCl3 R + R'H -> RH + R'

Question 27

What is addition/ substitution?

Answer 27

A radical can add to a molecule (double or triple bond) to form either a more complex radical or by rearrangement and elimination a substitution of one radical for another

Question 28

What is another name for addition/subtraction?

Answer 28

continuation/branching depending on whether more reactive radical are produced in these steps

Question 29

Give an example of addition/subtraction.

Answer 29

OH+ C2H3Cl -> C2H3OH+ Cl H+ C6H5Cl -> C6H6 + Cl

Question 30

What is combination/Recombination?

Answer 30

When two radicals, two atoms, or a radical and an atom combine, they form a new molecule

Question 31

What is another word for combination/recombination?

Answer 31

termination steps in a chain reaction

Question 32

Combination/recombination is the opposite of ____.

Answer 32

dissociation

Question 33

Give example of combination/recombination.

Answer 33

H+H-> H2 CH3 + CH3-> C2H6 H+ R -> RH

Question 34

What does this symbol mean " <-> "?

Answer 34

It indicates you are looking at a reversible reaction.

Question 35

All ____ reactions are reversible.

Answer 35

elementary

Question 36

____ determines the equilibrium state of a reacting system.

Answer 36

Thermodynamics

Question 37

How do you determine the rate law of a reaction?

Answer 37

If and only if we have an elementary reaction, you can find it from the reaction stoichiometry

Question 38

What is equillibrium?

Answer 38

The forward and reverse reaction rate become equal. The reactions are still taking place but there is no net change at this point r_f=r_r r_net=0

Question 39

How do you rearrange to group constants?

Answer 39

write kf/kr on one side and all of the other molecules on the other side by division kf/kr becomes kc