CHEMISTRY COMMUNITY

Jacob Motawakel

It depends whether the half-reaction is oxidized or reduced. In oxidized half-reaction, the electrons will be on the right side of the reaction because of the loss of electrons. In reduced half-reaction, the electrons will be on the left side of the reaction because of the gain of electrons.

Jacob Motawakel

Also, zero-order reactants have an exponent of zero, which makes the reactant negligible to the overall rate law.

Jacob Motawakel

After separating the redox reactions into two half reactions, you add H2O to balance oxygens in each half reaction, and add H+ to balance hydrogen in each half reaction.

Jacob Motawakel

a higher activation energy is a lower rate constant because the reaction occurs slower. It is an inverse relationship.

Jacob Motawakel

the salt bridge allows the flow of ions between the anode and cathode solutions.

Jacob Motawakel

yes k can change, but only due to temperature.

Jacob Motawakel

you would use an ICE table for this problem since you have an initial partial pressure and the k value

Jacob Motawakel

under constant volume delta U equals delta H because at constant pressure q equals H and at constant volume no work is being done, so in that case U=q which is U=H in contact pressure and volume.

Jacob Motawakel

yes you can use any one trial

Jacob Motawakel

you use the table to find the order of each reactant. To do this, you have to keep all reactants constant at two different experiments, except for the one you want to calculate. Then compare the quotient of the concentration of the reactant you want to calculate to the quotient of the initial reacti...

Jacob Motawakel

Activation energy is the minimum amount of energy needed for the reaction to proceed. Free energy is the difference in energy between reactants and products. Free energy is calculated as products minus reactants, so if the sign of the free energy is negative it is a spontaneous reaction, and if the ...

Jacob Motawakel

zero order means k is a constant, and it is not changed by differences on concentration of reactants. The rate law is just equal to k.

Jacob Motawakel

You can calculate K at different temperatures with the Van't Hoff equation. I don't see how it relates to DeltaG though because the only relation between DeltaG and K is with standard DeltaG, and since Van't Hoff equation doesn't calculate K at standard conditions, you can't use that K in the equati...

Jacob Motawakel

So if the catalyst is not present in the products of the final reaction, does that mean it is fully consumed throughout the overall reaction?

Jacob Motawakel

If we are given a chemical reaction formula and have the DeltaG values similar to that of the midterm, then we would use products minus reactants. However, if given entropy or enthalpy, I believe we would be prompted to use the DeltaG = DeltaH - TDeltaS.

Jacob Motawakel

T1 and K1 need to correlate, and T2 and K2 need to correlate. The order only matters in regard to changing whether there is a negative sign or not.

Jacob Motawakel

Yes, you can use concentration, mass, pressure, or whatever the problem indicates. I'm sure it will be stated in the problem or be able to be inferred which units to use.

Jacob Motawakel

Ka is the equilibrium constant for a weak acid dissociating
Kb is the equilibrium constant for a weak base dissociating
pKa = -log[Ka]
pKb = -log[Kb]

Jacob Motawakel

you use h2o to balance the oxygens in your half reactions, then depending whether it is in an acidic or basic solution, you use h+ and oh- to balance the hydrogens in your half reactions. h+ for acidic solution, and oh- for basic solution.

Jacob Motawakel

It is because entropy is the disorder in the universe, so as temperature approaches absolute zero, there is less and less disorder. You can think of it as high temperature is a higher state of disorder since molecules are moving more and moving faster, so low temperature would be slower and less mov...

Jacob Motawakel

n is the total number of electrons transferred, so when you get your final balanced reaction from the two half cell reactions, whatever number you used to cancel your electrons from the two half cell reactions is the number of electrons transferred.

Jacob Motawakel

Since you already found pH, you can use the equation pOH + pH = 14 to get 14 - pH = pOH and substitute your calculated pH.

Jacob Motawakel

you use the nernst equation and make Q = [anode]/[cathode]

Jacob Motawakel

because there are less moles on the right side, so as volume decreases, the side with less moles will increase.

Jacob Motawakel

yes because there is no more potential energy for the reaction to move in any direction.

Jacob Motawakel

If you add heat to this reaction, the concentration of products will increase since it is an endothermic reaction. I don't think you can add heat to a specific side.

Jacob Motawakel

If you add heat to this reaction, the reactants will increase in concentration since it is an exothermic reaction. I don't think you can add heat to a specific side.

Jacob Motawakel

You can use pKa to find the concentration of [H+] through an ICE box, then using the [H+] concentration, you can find pH by plugging [H+] into the equation pH=-log[H+]

Jacob Motawakel

You can find delta H either through products minus reactants, or Hess's law, or the Gibbs free energy equation delta G = delta H - T delta S

Jacob Motawakel

In a cell diagram, when there is no phase change, you separate with commas, if there is a phase change, you separate with a vertical line, and when changing from anode to cathode you use double vertical lines.

Jacob Motawakel

Balance each of the following skeletal equations by using oxidation and reduction half-reactions. All the reactions take place in acidic solution. Identify the oxidizing agent and reducing agent in each reaction.

(d) Reaction of chlorine in water:
Cl2(g) > HClO(aq) + Cl2(g)

How do you do part d?

Jacob Motawakel

You add H20 to balance the number of oxygens in acidic/basic solutions. You add H+ to balance the number of hydrogens in an acidic solution. You add OH- to balance the number of hydrogens in a basic solution.

Jacob Motawakel

To find the charge of Mn, you would first find the charge of oxygen in that compound, which is -2, and then multiply it by the number of oxygen atoms. So for MnO4- the oxygen part of the compound is -2*4, which is -8. Finally, to find the charge of Mn, you set the charge of Mn plus the charge of O4 ...

Jacob Motawakel

delta G is zero at equilibrium, but delta H and delta S do not have to be zero at equilibrium.

Jacob Motawakel

Isobaric means constant pressure, so at constant pressure q=deltaH, w= -PV.

Jacob Motawakel

An adiabatic process is when no heat is transferred.

Jacob Motawakel

You can use this equation to find when delta G is closest to delta H, to do this, you would find a reaction with the lowest entropy(delta S)

Jacob Motawakel

Elements in their standard state have an enthalpy of formation of zero, such as O2 and H2

Jacob Motawakel

Boyle's Law proves that volume and pressure are inversely related.

Jacob Motawakel

You have to account for phase change. Melting ice goes from solid to liquid, so you have to add the equation for solid: q=mCdeltaT, to the phase change equation from solid to liquid: q=mdeltaH. mass(m) can also be in moles(n).

Jacob Motawakel

delta U is zero at constant temperature

Jacob Motawakel

Intensive property does not depend on the amount, extensive property depends on the amount. An example of an intensive property is heat capacity, an example of an extensive property is specific heat capacity.

Jacob Motawakel

When q=-w, internal energy is equal to 0, which indicates constant temperature.

Jacob Motawakel

A system's work is negative when that system does work, Work is positive for a system if work is done on that system.

Jacob Motawakel

At constant pressure, Work = Pressure * Volume, q=Enthalpy, and at constant volume work=0 .

Jacob Motawakel

The Boltzman equation is used to find residual entropy .

Jacob Motawakel

I believe the temperature would be calculated in Kelvin since that is the standard temperature we have been using.

Jacob Motawakel

In an exothermic reaction when temp is increased, the reaction shifts towards the reactants, and when temp is decreased, the reaction shifts towards the products.

Jacob Motawakel

You need balanced equations so you can have the correct coefficients when calculating k. When calculating k the coefficients of the balanced equation become the exponents of the k equation.

Jacob Motawakel

Enthalpies can be negative, indicating an exothermic reaction.

Jacob Motawakel

Delta s is entropy. Delta h is enthalpy.

Jacob Motawakel

Pressure and enthalpy have a direct relationship, meaning that when pressure increases so does enthalpy.

Jacob Motawakel

Heme group has Fe in the center, and 4 N atoms binded with an additional 2 lone pairs of electrons on the Fe. An oxygen can bind to one of the lone pairs.

Jacob Motawakel

Lewis acids are electron acceptors, so the structure or compound that can accept electrons is a Lewis acid.

Jacob Motawakel

excess carbon dioxide reacts with water to make the acid H2CO3. The production of the acid H2CO3 makes the pH of our blood lower (acidic) which leads to respiratory acidosis.

Jacob Motawakel

Amphiprotic is more specific in saying that the compound can both donate and accept protons, but amphoteric just means a compound has acidic and basic properties, not the real principle of what it means to be a bronsted acid or base.

Jacob Motawakel

No, since strong acids and bases are completely dissociated, it is only a one way reaction. Weak acids and bases use the equilibrium sign because the weak acid/base is not completely dissociated, so there are still H+ or OH- ions on the reactant side, as well as some on the products side.

Jacob Motawakel

When there is too much CO2 in our bodies, it reacts with H20 and creates an acid H2CO3, which lowers the pH in our blood (acidosis).

Jacob Motawakel

The best resonance structure is when the central atom has a formal charge closest to 0, that is when the structure is most stable.

Jacob Motawakel

Equilibrium calculation are 14B because they require an ICE box, which Dr. Lavelle explicitly stated we would not have to do on the final.

Jacob Motawakel

Kw is used in the equation Ka*Kb=Kw, and pKa+pKb=pKw and -log[Kw]=pKw

Jacob Motawakel

Because As and Bi are along the metalloid line. The other ones we need to know are also that Metal oxides are basic, and nonmetal oxides are acidic.

Jacob Motawakel

Stronger intermolecular forces have a higher boiling point. If same IMF, such as LDF, the larger molecule will have a higher boiling point.

Jacob Motawakel

4 myoglobin make up one hemoglobin. Oxygen binds to myoglobin, and it is transferred in hemoglobin.

Jacob Motawakel

Hydrogen bonds are a bond between hydrogen and either O,F,N. Potential hydrogen bonding sites are a lone pair on an O,F,N atom binded to an H, or H binded to O,F,N.

Jacob Motawakel

HClO2 would be the stronger acid because it has a greater number of oxygen atoms attached to the central atom, making the oxidation number of the central atom greater.

Jacob Motawakel

The Cl atoms in cisplatin bind to the nitrogens with lone pairs on Guanine. Also, remember that cis cisplatin structure binds stronger than trans cisplatin structure.

Jacob Motawakel

HF bond is very small and strong, making it harder to dissociate in water.

Jacob Motawakel

you can't tell polarity just from the VSEPR formula. You need the VSEPR model to tell the shape.

Jacob Motawakel

Light is emitted if there is a quantum drop, and light is absorbed when there is a quantum jump.

Jacob Motawakel

The coordination number is the number of Ligands attached to the central transition metal

Jacob Motawakel

Amphiprotic means you could either lose a proton or gain a proton, like water. Amphoteric means being able to act as a base and an acid.

Jacob Motawakel

the force of attraction between two atoms is the absolute value of the product of the charges of the two atoms divided by the distance from each nucleus squared.

Jacob Motawakel

The least electronegative atom is in the middle of the lewis structure, and the other atoms are formed to meet the required number of bonds and lone electron pairs.

Jacob Motawakel

it is octahedral because there are 6 ligands: three NH3 and three Cl

Jacob Motawakel

There can be, coordination numbers can be as high as 12

Jacob Motawakel

Yes coordination compounds are always neutral.

Jacob Motawakel

Because in water it acts as an acid

Jacob Motawakel

Yes it is bent, VSEPR is AX2E1

Jacob Motawakel

Hydrogen bonds can only form with O, N, and F

Jacob Motawakel

Hydrogen bond > dipole dipole > london dispersion

Jacob Motawakel

In a polar molecule, there is a distinct dipole moment, and in a nonpolar molecule, there is no dipole moment because they cancel out.

Jacob Motawakel

Why are we not allowed to use the Rydberg equation frequency = R( 1/n1^2 - 1/n2^2)?

Jacob Motawakel

Which quantum number is the angular momentum?

Jacob Motawakel

I believe we just need to know how to write out electron configuration, but it would be useful to understand the shapes for conceptual problems.

Jacob Motawakel

It depends on the resonance structure. For example, if a resonance structure changed from a two double bonds to one single and one triple bond, than the triple bond has an increased strength than the previous double bond.

Jacob Motawakel

Their valence shells have enough orbitals to accommodate extra electrons.

Jacob Motawakel

The central atom is the atom with the lowest ionization energy.

Jacob Motawakel

Ionization energy increases from left to right because the atomic radius decreases from left to right, which results in a stronger pull between electrons and the nucleus.

Jacob Motawakel

within the energy level, the volume of space is called the orbital.

Jacob Motawakel

A quick tip for trends is that atomic radius increases as you go down and left, while ionization energy and electronegativity increase as you go up and to the right.

Jacob Motawakel

The negative implies that the structure has a negative charge and therefore more electrons. You would have to take this into account when making the Lewis structure by adding the additional electron to the total amount.

Jacob Motawakel

The electric field is a force field around a charged particle indicating the direction the electric force would push the particle. So I believe a change in the electric field is either a change in the charge of the particle, or a change on the electric forces around the particle.

Jacob Motawakel

The meaning of h is just the change of rate of energy because E=hv, and h is just the slope.

Jacob Motawakel

According to the wave model, frequency is the amount of energy in a single photon. This is proven in the experiment where increasing intensity of did not remove the electron, but increasing frequency of light did remove the electron. In this experiment it shows that frequency is the energy in a sing...

Jacob Motawakel

Yes, the ionization energy is the energy it takes to remove an electron, making it the threshold energy. So the energy of the light has to be equal to or greater than the threshold energy to successfully surpass the threshold energy, and remove the electron.

Jacob Motawakel

You would round up to 64%

Jacob Motawakel

Accuracy is how close the obtained value is to the correct value. Precision is how close the obtained values are to each other.

Jacob Motawakel

Test number 1 is during your discussion this upcoming week, and it covers the fundamentals of chemistry we have been reviewing.

Jacob Motawakel

To convert 2.29 x 10^-4 grams to micrograms, you would have to use the conversion factor of 1 x 10^-6 grams which equals 1 microgram. So by using this conversion, you would do (2.29 x 10^-4 grams) x (1 microgram/1 x 10^-6 grams) = 2.29 x 10^2 micrograms.

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