Chem final Flashcards
Catalyst
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
Branched chain Alkane
have atleast one side chain distinguished because they have atleast one carbon atom joined to atleast 3 other carbons (1-methylbutane)
Straight chained alkane
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
alcohol formula and example
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
Order names for Alkanes/ alkenes alkynes
Meth = 1 Eth = 2 prop = 3 but = 4 pent = 5 hex = 6 hept = 7 oct = 8 non = 9 dec = 10
Molar heat capacity
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
Specific heat
Heat required to raise the temperature of 1g of material by 1 kelvin
Heat/mass(Delta) T
Using your knowledge of kinetics, would you expect the reaction….. NO + O —–No2 Fast or slow?
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
Hess’s law
The enthalpy change during a proccess is independent of the path taken from reactants to products
Standard Enthalpy of formation
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
3 rd law of thermodynamics
Entropy is a 0 for a perfect crystal at a temperature of 0 k
2nd law of thermodynamics
Entropy increases in a spontaneous process
Delta s> 0
1 st law of thermodynamics
energy cant be created nor destroyed
Delta U= q + w
State function
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
Integrated 1 st order
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
Half life of a chemical reaction
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
Rate constant
The rate constant K= constant in rate equation does not change with change in the concentration
Order of reaction
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
Conformer vs isomer
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
Carbocation stabilty
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
Carbon Stability part 2
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
Potential energy vs Progress of reduction graph. Endothermic RXN
Remember to draw from below and with AE
Chain reaction
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
Chiral molecule
A carbon atom bound to four different groups.
