Chem final

Question 1

Catalyst

Answer 1

Reduces the activation energy of RXN therefor increasing the rate of the rxn. The catalyst is left unchanged it simply provides an alternate, lower energy pathway for the rxn

Question 2

Branched chain Alkane

Answer 2

have atleast one side chain distinguished because they have atleast one carbon atom joined to atleast 3 other carbons (1-methylbutane)

Question 3

Straight chained alkane

Answer 3

Straight chained alkane. All the carbon atoms are in the single, unbranched chain. Can be distinguished because there will be no carbon atom in the chain that is bound to more than 2 other carbons

Question 4

alcohol formula and example

Answer 4

Cn H2n+1 OH OR R-OH

Think of alcohols can be cyclic and in which R-OH is the formula rahter than CnH2n+1 OH

Question 5

Order names for Alkanes/ alkenes alkynes

Answer 5

Meth = 1
Eth = 2
prop = 3
but = 4
pent = 5
hex = 6
hept = 7
oct = 8
non = 9
dec = 10

Question 6

Molar heat capacity

Answer 6

Heat required to raise the temperature of 1 mole of material by 1 K

Obtain this value by multiplying the amount of grams in a mole by the specific heat capacity of this substance

Question 7

Specific heat

Answer 7

Heat required to raise the temperature of 1g of material by 1 kelvin

Heat/mass(Delta) T

Question 8

Using your knowledge of kinetics, would you expect the reaction….. NO + O —–No2 Fast or slow?

Answer 8

To be very fast because reaction is simple species in reaction are very reactive there is not likely to be any steric problems and the product is rather stable

Question 9

Hess’s law

Answer 9

The enthalpy change during a proccess is independent of the path taken from reactants to products

Question 10

Standard Enthalpy of formation

Answer 10

Enthalpy change for the formation of 1 mol of a substance from the elements in their standard states. Must be the formation of 1 mol of a single compound

Question 11

3 rd law of thermodynamics

Answer 11

Entropy is a 0 for a perfect crystal at a temperature of 0 k

Question 12

2nd law of thermodynamics

Answer 12

Entropy increases in a spontaneous process

Delta s> 0

Question 13

1 st law of thermodynamics

Answer 13

energy cant be created nor destroyed

Delta U= q + w

Question 14

State function

Answer 14

A measure of a system dependent only on its current state. The value of a state function depends only upon the current state of the system not its past history Examples temperature, entropy, Gibbs free energy, Enthalpy

Question 15

Integrated 1 st order

Answer 15

To be used in situations when given a question with a % decrease and a time over which this has occurred. RXN A— prods 1st order. The concentrations of A decrease by 4% in 8.00 mins. what is K

Question 16

Half life of a chemical reaction

Answer 16

Time required for the concentration of a reactant to fall by fifty percent.

Half life of a first order RXN= ln2/k=0.693/K

Question 17

Rate constant

Answer 17

The rate constant K= constant in rate equation does not change with change in the concentration

Question 18

Order of reaction

Answer 18

The order of reaction with respect to a reactant is the power to which that reactant is raised. Order of rxn with respect to teh WHOLE EQUATION is all the consituent powers added together

Question 19

Conformer vs isomer

Answer 19

Isomers are molecules that share the same molecular formula, but are arranged differently, one isomer cannot be converts into another @ room temp. Therefore are considered two different molecules conformers rotate about a single bond and can be convert between cis and trans. Steriochemical isomers

Question 20

Carbocation stabilty

Answer 20

The least stable carbocations are those in which the positive charge resides on the carbon connected to the smallest # of other carbons. EXAMPLES C+ attached to 3 carbons

Question 21

Carbon Stability part 2

Answer 21

Why is the least stable carbocation attached to teh leave # of other carbons. B/C electron density can be DONATED BY CARBONS to reduce the effective charge on the carbon that bears the positive charge, therefore making it less electrophyllic and more stable

Question 22

Potential energy vs Progress of reduction graph. Endothermic RXN

Answer 22

Remember to draw from below and with AE

Question 23

Chain reaction

Answer 23

Reaction with reactive species (radical) which is essential for reaction to occur is consumed in one step and regenerated in a following step.

RXNs of halogens w/ alkanes are chain rxns, in which the chain carying species is a haloggen such as Cl

Question 24

Chiral molecule

Answer 24

A carbon atom bound to four different groups.

Question 25

Electrophile

Answer 25

An electron loving species anything with a positive charge is electrophillic such as a carbocation or the H+ ion

Question 26

Substitution rxn

Answer 26

An atom or group in one molecule is replaced by an atom or a group from a second molecule
Usually H is removed from a alkane and replaced by a CL

Question 27

Addition reaction

Answer 27

A reaction in which a molecule such as HCL adds itself to a double bond in a rxn thus breaking the double bond

Question 28

cis /trans isomerism

Answer 28

AKA geometric isomerism. Describes the relative orientation of functional groups. Generally containing double bonds that cannot rotate.

Question 29

Structural isomer

Answer 29

Structural isomers share the same molecular formula. but have different arrangements of the atoms in space.

Question 30

units of rate constant K in 1sr order rxan

Answer 30

time -1

Question 31

Unsaturated compound

Answer 31

A compound that contains one or more double bonds and/or a ring structure

Non cyclic saturated structures undergo addition reactions which saturdate the molecule

cyclic parametric structures wish to retain aromoticty thus under go substitution