CHEMISTRY COMMUNITY

tierra parker 1J

is it because the pressure is also changing that you can't use the nCln(T2/T1) equation?

tierra parker 1J

i just remember that reduction reactions have electrons on the reactant side and it helps because they both start with the letter R

tierra parker 1J

you include H+ not H2O but the rest seems right

tierra parker 1J

for the last part of the question, it asked which was more thermodynamically stable the disassociation of F2 or Cl2 and the answer is Cl2 because it has a smaller equilibrium constant but why?

tierra parker 1J

to calculate the degree for each reactant you have to compare each experiment and see how changing the concentration of one reactant impacts the total rate of the reactant. for element c, you can see in experiment 1 and experiment 4 the concentration of a and b aren't change but the concentration of...

tierra parker 1J

zero order reaction means that the concentration the reactant has no effect on the rate of the reaction so even if you increase the amount of reactant the reaction will proceed at the same time. the unit for the rate constant will be M/s

tierra parker 1J

i personally don't know the exact reason why but if you try it with the first reaction they give you in the chart (btw i have the seventh edition). the rate law = k[H2][I2] and if you're just considering the units for the problem the left side or the rate has units of M/s while the right side is L/m...

tierra parker 1J

you got the two mixed up, for basic solutions you use OH- and H2O and for acidic solutions you use H+ and H2O, but the question should tell you whether or not they want you to balance the equation in a basic or acidic solution

tierra parker 1J

liquids are in the same like bracket as gases i believe

tierra parker 1J

i think it has to do with the fact that if K < 1 then there are more reactants than products at equilibrium so the reaction sits to the left making the reverse reaction favorable

tierra parker 1J

we don't have to memorize the oxidation states for transition metals since they could have more than one, but we should know the oxidation states of like carbon, hydrogen, and oxygen

tierra parker 1J

so is the answer that products are more stable

tierra parker 1J

mostly gibbs free energy

tierra parker 1J

i was reading the solution and i was wondering why do you have to find the entropy in three steps rather than two?

tierra parker 1J

i don't think you can use that equation with the 5/2R because the pressure isn't constant. since it's a compression if volume decrease then pressure increases

tierra parker 1J

when you're trying to find the entropy change of an ideal gas reversibly, do you use the equation with temperature in kelvin or celsius?

tierra parker 1J

isothermal means temperature is constant so delta u is zero and isometric means volume is constant so work equals zero.

tierra parker 1J

Sophia Ding 1B wrote:Are we always supposed to being the unit for atm in terms of calculations with pressure?

i think it depends on which constants you use like if you use R = 0.08206 L atm/K mol then you use atm but they also give you R = 62.364 L Torr/K mol on the equation sheet

tierra parker 1J

what are the units for enthalpy, is it just joules?

tierra parker 1J

since 02 is normally found as a diatomic molecule so there is no need to form the molecule which gives a zero enthalpy of formation

tierra parker 1J

https://courses.lumenlearning.com/intro ... for-water/

i couldn't figure out how to insert a picture of the heating curve so here's a website.
this is for reference of the answer above mine.

tierra parker 1J

the system is the gas and everything else around it is the surroundings. heat is being added to the system so 524 kj is positive then work is being done to the system so 340 kj is also positive then the total change in internal energy is the two numbers added together.

tierra parker 1J

in terms of Ka values i think for weak acids the Ka value is very small compared to that of a strong acid but i dont know if that applies for weak bases

tierra parker 1J

i'm guessing it's because solids and liquids usually aren't affected by changes in pressure like gases are.

tierra parker 1J

for this problem they give you the Kw of water and it is 2.1 x 10^-14 and you have to find the hydronium and hydroxide concentration. in the answer explanation they made the two equal is it because it's water that hydronium and hydroxide equal?

tierra parker 1J

if k=1 wouldn't that mean that the reaction is at equilibrium?

tierra parker 1J

the conjugate base comes from an acid after it loses the proton, ie sulfuric acid H2SO4 its conjugate base is HSO4-

tierra parker 1J

the concentration H2 would increase because you want to keep the equilibrium constant the same so if you increase CO then the same would happen to H2

tierra parker 1J

I'm still confused on how to find the change in molarity, can someone explain please? Does the number in front of the X come from the coefficient that is in front of the reactant or product? yes the coefficient of x is from the coefficients from the balanced equation. if the equilibrium concentrati...

tierra parker 1J

can someone explain the so what of equilibrium like what can you do knowing what the equilibrium of a reaction is?

tierra parker 1J

so when you find q and you see that it is smaller than k then it means that the forward reaction is favored. my question is does that mean that the reaction needs to continue for a period of time before equilibrium is reached?

tierra parker 1J

this may be a dumb question but is the ammonium ligand spelled amine or ammine?

tierra parker 1J

i find bond lengths by doing lewis structures. single bonds are the longer, weaker bonds. double bonds are in the middle. triple bonds are the shorter, stronger bonds.

tierra parker 1J

the concentration should be in moles/liter (M)

tierra parker 1J

H2S does not have hydrogen bonds because hydrogen bonding only occurs when a hydrogen bonds with oxygen, fluorine, and nitrogen. H2S has dipole-dipole because when you draw out the lewis structure you see it is polar. H20, on the other hand, has hydrogen bonds and since hydrogen bonds are the strong...

tierra parker 1J

it's not t-shaped because t-shaped would have three bonds attached to the central atom and two lone pairs (AX3E2) but it is linear because i think the three lone pairs on the central iodine balance out the three lone pairs on the other two iodine.

tierra parker 1J

ionization energy is the energy to remove an electron and it decreases as you move across a period. it decreases because the more electrons an atom has the stronger the attraction it has towards the nucleus making it harder to remove an electron. magnesium has more electrons so it is harder to remov...

tierra parker 1J

the orientation would be in a tetrahedral shape and the angle would be less than 109.5

tierra parker 1J

double bonds do not affect the vsepr model because they are thought of as single regions of electron density and for lone pairs you draw an electron cloud

tierra parker 1J

NF3 has hydrogen bonding because the hydrogen is bonding with the very electronegative nitrogen. this molecule is polar which makes it dissolve in water.

tierra parker 1J

A represents the central atom and there can only be one central atom so no subscript is needed

tierra parker 1J

they are the same shape

tierra parker 1J

sigma bonds are single bonds and pi bonds are double or triple bonds. the bond order is the number of bonds between two elements.

tierra parker 1J

in lecture, lavelle was talking about how HCl has a permanent dipole moment and I was wondering how do we know that.

tierra parker 1J

no because electron affinity is the energy released when an electron is added but since the noble gases have fulled valence shells it requires energy to add an electron so the elements with the highest electron affinity are in the top of group 17.

tierra parker 1J

[Kr] 4d4 5s1

tierra parker 1J

copper has the electron configuration [Ar] 3d10 4s1 because it is more stable to have a full d shell than a partially full d shell and a full s shell. also since the 4s shell has more energy you take the electrons from that shell first so you're left with Cu 2+ as [Ar] 3d10

tierra parker 1J

Ag has the electron configuration has [Kr] 4d10 5s1 when you take one electron out of the shell it comes from the highest energy which is 5s shell and it is also more stable to have the full d shell than a full s shell.

tierra parker 1J

since the electron configuration shows only the 3d and 4d shell so it is implied that the 4s shell was taken first because it has the higher energy. for the first one the two electrons are coming from the 4s shells and the final configuration is [Ar] 3d7 4s2 which is Cobalt so the ion is Co 2+.

tierra parker 1J

they are essentially the same thing just when if a question asked how many electrons are paired in the first way you wrote it you know the last two electrons aren't paired and are parallel

tierra parker 1J

I don't think we need to know the specific axis pairing. I think we just need to know that the d orbital has five different pairings

tierra parker 1J

c = λv (v is frequency)
p = mv
E = pv (v is velocity)
for a photon the speed is the speed of light so E=pc and E=(hc)/ λ
so pc=(hc)/ λ
λpc=hc
λ = h/p (de Broglie)

tierra parker 1J

eV = electric volt which is the amount of energy in an electron
KeV = kilo-electric volt so multiply that quantity by 10^3
there is 1.602 x 10^-19 J = 1 eV
then you would proceed by using E = hc/lambda

tierra parker 1J

I think you should know which wavelengths correspond to visible light (400 nm -700 nm) and know the order of smallest to longest wavelengths (gamma ray, x-ray, ultraviolet, visible, infrared, microwave, and radio wave)

tierra parker 1J

They refer to the different special lines electron transition to. So for the lyman series means that electrons transition to the first energy level (n1), balmer series transition to the second energy level (n2), and paschen series transition to the third energy level (n3)

tierra parker 1J

you would begin by converting the megahertz to hertz by using the conversion factor that 1 MHz = 1,000,000 Hz then whether you're given energy, wavelength, or frequency you would use the equation speed of light = wavelength x frequency or energy = planck's constant x frequency.

tierra parker 1J

hertz is equivalent to per second (1 s^-1) so in the equation E=hv, h has units of J x s and v has units of 1/s so when you multiply the two cancel out to get J which is the unit for energy

tierra parker 1J

The amount of sig figs in the constant should not affect the amount of sig figs in the final answer; only the amount of sig figs in the calculated values affect the answer.

tierra parker 1J

They are the same thing. Reagent would be what you physically have in the lab and reactant is what you would read and write on paper.

tierra parker 1J

Thank you I got the balancing equation now but now I am trying to convert tons to kilograms but the appendix has two different values ( 907.18474 kg or 1016.046 kg) so I don't know which one to use.

tierra parker 1J

I am also confused about this problem because I could balance the first two equations but I am unable to balance the last equation (Fe3Br8 + Na2CO3 ---> NaBr + CO2 + Fe3O4) so how should I about balancing the final equation?

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