General Chemistry Flashcards
whatWhat is periodic law?
the chemical and physical state properties of elements are dependent in a periodic way upon their atomic numbers
Since the rows are periods and the groups are columns what does this have to do with their properties?
groups contain the same electron configuration in their valance shells and share similar properties
Describe the concept of valance shells and its importance?
valance electrons are the electrons farthest from the nucleus and they also have the greatest amount of potential energy the higher this energy the nucleus powerful positive centrer has less of a hold or grip on the electrons and they move to bond with other elements to gain some stability the valance shell determines chemical reactivity and properties of the element.
Describe the concept of metals in the periodic table?
metals are lustrous with the exception of mercury, they have high melting points they re malleable the are ductile meaning can be made into wires, the have low effective nuclear charge and low electronegativity they are good conductors, alkalli and alkaline earth metals are metallic because they can easily loose electron from the S orbital of valance shell.
Describe the concept of nonmetal in the period table?
nonmetal are the opposite of metals as the name implies they are brittle non lustrous, they are bad conductors, high electron infinity and what to bond readily they are mostly the molecules use in organic compound so think about humans we are not good conductors.
What are metalloids?
these are elements on the periodic table that are an intermediate between metals and nonmetals they share the traits between the two.
Describe the trend of atomic radius vs ionic radii?
Atomic radi: the size of a neutral element (opposite of all other tends increasing going up and to the right.)
ionic radii: dependent on how the element ionizes base on element and group
Describe the concept of ionization energy?
energy require to remove and electron from a gaseous species
> this require the input of energy from the the atom so it result in heat or endothermic process.
> the greater the zeffic the close the VS is to the nucleus and the tigher the bond
> increase from right to left.
Describe the concept of electron affinity?
energy dissipated by and element after gaining an electron, by gaining this electron the halogen completes to octet rule thus releasing energy making it exothermic
What is the concept of electronegativity?
measure of attractive forces that an atom will exert on an electron in a chemical bond the greater this force the more it attraction electrons within a bond.
meTals loose electrons to become
caTions which have a posiTive ion (+)
Nonmetals gain electrons to become
aNions which will have a Negative charge (-)
What is the relationship between bond length and bond strength?
they are inversely related, the longest bonds are also the weakest thus single bonds are the longest but are the weakest, and triple bonds are the shortest but the strongest.
What is the concept of bond energy
this the energy required to break a bond by separating elements, more shared atoms the more energy that is required to break the bonds
> triple have the greatest bond energy
What is a polarity?
this occurs when atoms have a difference in electronegativity
> atom with the highest electroneg will get a larger electron density and create a dipoles
Describe the unique form of bonding that is hydrogen bonds and what is its importance in biological systems?
their is no sharing of electron
> it is between the three most Eneg atoms (oxygen, Nitrogen, Florine)
> the hydrogen acts a naked proton creating high boiling points to break these bonds (water for example)
> we would not exist without hydrogen bonds!
What is solubility?
maximum amount of that substance that can be dissolved in a particular solvent at a given temperature
If a solution is said to be saturated what does that mean?
the maximum amount of solute has been added and dissolved solute is in equilibrium and its undissolved state and even if more solute is added it will not dissolve!
What is the main difference between dilute and concentrated?
Dilute is going to be a reference to a small amount of solvent
> concentration is going to be a larger amount of solute or solvent.
What are the two main solubility rules?
- all salts contaning ammonium and alkali metal group cations are water soluble
- all salts containing nitrate and acetate anions are water soluble
Collagative properties:
physical properties of solutions that are dependent on the concentration of dissolved particles but not on the chemical identity of the dissolved particles
What is Roults law?
accounts for vapor pressure depression cause by solutes in a solution as the solute is added to a solvent the vapor pressure of the solvent decreases proportionately.
When will Raoults law deviate and turn into Ideal solution?
RL hold only when the attraction between the molecules of the different components of the mixture are equal to the attraction between the molecules of any component in its pure state when this is no longer true it turns into ideal solution.
What are the four variables used to measure a gaseous state?
pressure, volume, temperature, and number of mols
What is ideal gas law?
gas with molecules that have no intermolecular forces and occupy no volume
What are real gases?
do not follow the behavior of ideal gases at high pressures and low temperatures may compressed gases have behaviors that are close to ideal.
What is density?
mass per unit of volume for a substance
How does Avogadros principle apply to gases?
it states that all gases at a constant temperature and pressure occupy volumes that are directly proportional to the number of moles of gas. equal amounts of all at the same pressure and temperature will occupy the same volume.
As the number of mole of a gas inc. the volume will?
inc. in direct proportion
What is Boyles law?
This law states that pressure and volume are inversely related meaning if one increase the other decreases
What is Charles law?
law states that temperature and and volume are directly proportional which one increases so does the other.
Why are enzymes important what is there role?
enzyme selectively enhance the rate of certain reactions over other thermodynamically pathways, every reaction in a biological system would move too slow if it were no for enzymes and catalytic substances.
What are the two types of reactions and what are they due to?
reactions can be Spontaneous or nonSpontaneous and they are due to change in gibbs free energy
Gibbs free energy:
the energy of a system available to do work often referring to enthalpy which is a change in temperature or and negative delta G indicates a spontaneous reaction and + delta G indicates a non-spontanouus reaction.
What is the rate determining step?
this is your slowest step in the reaction, because it acts like a kinetic bottleneck preventing the overall reaction from proceeding any faster than the slowest step.
Collision theory:
states that the rate of reaction is proportional to the number of collisions per second between the reacting molecules.
What is an effective collision?
one that leads to the formation of products and occurs only if the molecules collide at the right orientation with enough energy to break their existing bonds and create new one ( this concept is often called activation energy or the energy barrier)
What is true about the rate constant and low activation energy?
low activation energy and higher temperatures creates an increase in the reaction rate
Compare the number of collisions are high and low concentrations?
> high concentrations: more collision
> low concentrations: less collisions
What is a transition state?
molecules collide with energy equal to or greater than the activation energy they form a transition state in which old bonds are weakened and new bonds begin to form.
Exergonic:
negative free energy, means energy is given off
Endergonic:
positive free energy, means energy is absorbed
What are the factors that affect the reaction rate?
- Reaction concentration
> the greater the conc. the greater the effective number of collisions - Temperature
> increase in temperature will increase reaction rate because you are increasing the overall kinetic energy - Medium
> depends on intermolecular forces, and polarity of solutes and solvents. - Catalyst
> substances that increase the rate of reaction without being used themselves, they interact with the reactants either by adsorption or through the formation of intermediates and stabilize them to reduce the activation energy necessary for a reaction to proceed.
How do catalyst work?
they can increase the freq of collision, change the relative orientation of the reactants, make a higher percentage of collisions effective, donate electrons to the reaction or reduce intramolecular bonding within a reaction
what is an Arrhenius Acid?
this donates a proton (H+) IN AQU SOLUTION
What is a Arrhenius Base?
this donates a hydroxide (OH-) IN AQU SOLUTION
what is the combination definition of an acid according to lewis and bronseted?
this is a something that accepts a pair of electrons and donates a proton
what is the combination definition of an base according to the lewis and bronsted?
this is something that donates a pair of electrons and accepts a proton.
what happens if you were to put a strong acid or strong base in an aqu solution?
the acid and base will completely disassociated
what are the strong acids and want is the mnemonic that goes with them?
So I BRought NO CL CLOthes H2SO4 HI HBR HNO3 HCL HCLO4
The stronger the acid/base the?
weaker the conjugate base/acid
what is an amphoteric species?
species that can behave as an acid or a base. (I.E Water!!)
what is the acid/base dissociation constant?
this tells us how much will disassocated into solution a
the higher the Ka/Kb?
the stronger the acid/base
the lower the pKa?
the stronger the acid
the higher the pKa/pKb?
the weaker the acid/base
what is a buffer?
the ability to resist changes in ph, an ideal buffer is +1 to -1 of the pH. and these are made out of weak acid/bases and there conjugates
in the buffer system of the blood if you have an increase in the H+ ions or you have metabolic acidosis what will happen?
if you have an increase in H+ it will react with excess bicarb in the blood to create carbonic acid creating hyperventiation
in the buffer system of the blood in you have an increase in the bicarbonate or you have metabolic alkalosis what will happen?
if you have excess bicarbinate that means you have lower amounts of H+ so your breathing will slow down to try and keep acidic CO2 in the blood to help with the extra base you have.
what is the buffer system in the blood an example of?
le chateliers principle that if you add stress to a system it will shift to relieve that applied stress.
what is the Equivalence point in a titration?
the point at which equal amounts of acid and base in a solution. this is the point on the graph where 100% of the acid has been depro
what is the half equivalence point or midpoint in a titration graph?
this is the point in which half of the base equivalence to compensate for addition of acid in the beginning of the reaction
In a titration what is the best buffered region?
at the midpoint or half equivalence point. this is when you have 50/50 pro/depro of the acid.
what has Rutherfords contribution to Chemistry?
in 1911 he discovered that electrons surround the nucleus
what is the Bohr model?
this was invented in 1913 and described that obitals, the farther the orbital the more energy and a a photon is emitted when you move down in energy and a photon is absorbed when you move up in energy,
what is the concept of Heisenberg Uncertainty?
this is the concept that it is impossible to know the momentum and position simultaneously
what is Hunds rule?
electrons only double up in orbitals if all the orbitals are filled first and have 1 electron each.
what is the pauli exclusion principle?
that electrons must be paired +1/2 -1/2
what is Zeff?
this is the effective nuclear charge this is how much of protons positive charge in the nucleus makes it over to the valance electrons
What are sheilding electrons?
these are any electron already in completed orbitals that absorb some of the charge from the nucleus.
Relate Coulumbs law to period table trends?
F or force is equal to Q1 or change of valance E- (constant) times Q2 which is the Zeff all over Radius Squared
F=Q1Q2/R^2
as you move down the period table you?
increase the distance between the nucleus and the electrons because you are adding shells. (or inc. the Radii)
What is the trend of the Zeffect?
it moves right across the top of the table
what is the ionization effect?
this is the energy to loose an electron and pull it away it increase bottom to top and to the right.
what is the Electron affinity?
this is the energy to gain an electron and increases as you go to the right of the periodic table
What is Electronegativity?
the force require to pull electrons in a covalent bond, it increases up the periodic table and to the Right.
Describe the trend in atomic Size?
if you have more electrons in the outer shell the electrons will repel each other and make the radii greater if the force from the nucleus is smaller so this trends to the left and down to the bottom
What is a covalent bond?
formed via the sharing of electrons between two elements of similar electronegativity
What is Bond order?
the refers to whether a covalent bond is a single, double or triple bond.
describe the trends in bonds?
as bond order increases so does bond strength, bond energy and bond length dec.
What is the strength order for the intermolecular forces?
- Hydrogen bonds (strongest)
- Dipole-Dipole
- London Dispersion (weakest)
how many sigma bonds in a single bond?
1
how many sigma and how many Pi bonds in a double bond?
1 sigma, 1 pi
how many sigma and Pi bonds in a triple bond?
1 sigma, 2 Pi
What is the empirical formula?
most simple whole number ration of atoms
what is the molecular or chemical formula?
shows the exact number of atoms in each element for a molecule or compound
Describe the difference between the Empirical vs molecular formula when it comes to glucose?
Glucose: C6H12O6
Molecular: C6H12O6
Emperical C6H12O6/6 = CH2O
What is a combination reaction?
two or more reactants forming 1 product this is also called a synthesis reaction
What is a decomposition reaction?
single reactant creating two products
what is a combustion reaction?
a compound contaning carbon and hydrogen (sometimes oxygen) combine with oxygen to create CO2 + H20
what is a common example of a combustion reaction?
Break down of glucose! C6H12O6 + O2 –> CO2 + H20
What is a single displacement?
1 element starts off by it self then an atom/compound is replaced by that element “im Leaving you for your friend”
Cu + AgNO3 —> Ag + CuNo3
What is a Double Displacement reaction?
when positive and negative ions swap places, I.E Wife swap
CaCl2 + AgNO3 –> Ag + Ca(NO3)2
What is a neutralization reaction?
a reaction when you react a strong acid with a strong base creating salt and water
HCl + NaOH –> NaCl + H2O
what is the rate law?
the amount of reactants that are being consumed.
R= k[A]^m
What is the rate law in a zero order reactions?
the rate is equal to K which is the rate constant
what is the rate law in a first order reaction?
the rate is equal to K [A] which is the concentration of A times the rate constant
what is the rate law in a second order reaction?
the rate is equal to K[A]^2 which is the rate constant time the concentration of A to the power of 2
what happens in the MM- EQ when it comes to reaction orders for enzymes?
at low substrate concentration the reaction is at first order. At high substrate concentration the reaction is a zero order.
What is equilibrium?
the state in which all concentrations of reactants and products remain at a constant rate or the rate of product formation is equal to rate of product break down
is equilibrium static?
No, Equilibirum is not static just the forward and reverse are happening at the same time.
What is Keq?
this is the product over the reactants with there stochiometric coefficents
what are the rule for Keq?
you can only use Aq solutions of gases no solid or pure liquids
what is the reaction Quotient or Qc?
this value gives incite on the current concentration no equilibrium
What happens when your Q is higher then K?
Either too many product, no enough reactants or both shifting equalibirum to the products
what happens when you K is higher that your Q?
either too many products, not enough reactants or both shifting equilibrium to the reactants.
What is an Isolated System?
exchange neither matter nor energy with the environment
what is a closed system?
can exchange energy but NOT matter with the environment
what is an open system?
Can exchange Both energy and matter with the environment
What is a isothermal process?
constant temperature
what is an adiabatic process?
a process where no heat it exchanged with the environment
What is an Isobaric process?
Constant pressure
what is an Isovolumetric process?
constant volume
what is fusion?
going from a solid state to a liquid state
what is freezing?
from liquid state to solid state
what is vaporization?
liquid to gas
what is sublimation?
solid to gas
what is deposition?
gas to solid
what is superficial fluid?
where the density of the gas equals the density of the liquid no distinctions between those two phases
on an energy diagram the rate determining step is at step in a reaction?
the step that has the greatest activation energy is the slowest
what is a reaction mechanism?
seq of 2 or more simple reactions that combine to form an overall reaction
what is your rate determining step
your only as fast as your slowest step meaning your rate determine step is your slowest step.
intermediates:
substance produced in 1 elementary step and consumed in another
Catalyst:
in a rate of reaction remains unchanged and not consumed
