CHEMISTRY COMMUNITY

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So we would want to remember the 6 functional groups?

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How do you know whether to use Cv=(3/2)*R or Cp=(5/2)*R?

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Just to clarify:
If a 2nd order rate looked like rate = k [OH-] [H3Br]
the rate is second order for the reaction
but the rate is first order for each reactant?

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I'm confused as to what we need to know for electrolysis for the final?

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In the 7th edition, 6L #3 part a it asks for the half reactions for problems like Ni(s) | Ni2+ (aq) || Ag+ (aq) | Ag (s) are the half reactions: Ag+ (aq) + e- --> Ag (s) E(cathode) = +0.80 V Ni2+ (aq) + 2e- --> Ni (s) E (anode) = -0.23 V OR ARE THE HALF REACTIONS (with the reversed anode half reacti...

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So you would set it up the half reactions like: Cl2 (g) --> HClO (aq) + Cl2 (g)
Cl2 + 2 H2O --> 2 HCLO(g) + 2H+
Cl2 --> Cl2 (g)??

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E not is made up of state functions so therefore it is a state function

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In the 7th edition, 6K #3 asks that you balance the following redox rxn in an acidic solution and find the oxidizing/reducing agent. Part d had the equation) Cl2 (g) --> HClO (aq) + Cl2 (g) The answer is H2O (l) + Cl2 (g) --> HOCl (aq) + H+ (aq) + Cl- (aq) where Cl2 is both the oxidizing and reducin...

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Should we be using the periodic table reference in the text or the list of potentials in the textbook?

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You need something for it to attach to (a solid). I'm not exactly sure why it has to be Pt though

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how do you know when you need to add OH-

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You just want to make sure delta G is negative. So if the equation (ΔG=ΔH−TΔS) is manipulated in a way in which delta G is negative, it is spontaneous.

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Are the other parts of thermodynamics section going to be included?

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I thought when delta E was positive, system was gaining Energy?

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I think it has something to do with the fact that Cp= Cv+R. Since Cv=3/2 R that would mean Cp= 3/2R + R = 5/2R

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You can also solve for each one individually and then add them together

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Why is it that molecules like O2 and N2 not included when trying to figure out enthalpy of a reaction...?

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In the 7th Ed. section 4c. #3 it asks that you find the final T and change in enthalphy when a) @ constant pressure and b) @ constant volume
I know when there is constant pressure the change in enthalpy, delta H= q
Is it the same for when there is constant volume?
delta H=q???

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Thank you!
Do you think that this explanation makes sense: Since the reaction released the 3.5 kj, the calorimeter is getting the 3.50kj of work done on it.. So when work is done on the system (calorimeter), it is (+)?

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How do you know which Gas constant, R to use 8.206 e-2 L atm k-1 mol-1 or 8.314 e-2 J k-1 mol-1?

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In the 7th Ed. Section 4A Q13, the problem states "a constant volume calorimeter was calibrated by carrying out a rxn known to release 3.5 kJ if heat in 0.2 L of sol. in the calorimeter (q=-3.50kJ). When calculating C, the solutions manual changed the q from -3.50 kj to + 3.50 kj...why?

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heat=energy and enthalpy is the transfer of heat/energy

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What are some examples of both?

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In class, Lavelle used Kelvin and Celsius interchangeably when describing specific heat. How is it that that the heat required to raise the temperature of some ethanol is 49 kJ/C* or kJ/K?

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It can be helpful to view heat as a reactant since it is endothermic according to the explanation in the response above.

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If they give you barr and a volume that is not 1.0L is that volume significant? As in, do we need to change the barr by dividing it by volume?

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What is the correlation between how small/big the equilibrium constant is in comparison to the stability?

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In what cases would we need to manipulate the equation then when there is a temperature change?

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increasing pressure favors the side with fewer moles of gas, in this case it would be reactants

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The rule of thumb is that salts completely dissassociate

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I understand that volume and pressure are inversely related, I'm still a little confused about how this correlates with favoring the side with more moles?

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I think we've learned how to find Kc and Kp (the way to do it for each is essentially the same) however we have not learned how to convert between the two. We know how to take pressure to concentration.

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Does 'K' most often refer to Kp or Kc?

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There's a table in the textbook that shows that Na+ is a neutral in acid/base rxns so in the net equation it is not included.

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For weak acids/bases since they do not deionize completely, the arrow should be that of constant equilibria between reactants and products (one arrow for forward rxn and one arrow for backward rxn). However in the textbook (7th ed) in Fundamentals J question 17 a-d that asks for the chem eqn for the...

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How would the composition of a sigma bond with a hydrogen be written. i.e. a single bond between H and C
Would it look something like sigma (C 2sp^3 , H s)?

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so not necessary when we name them?

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When naming complex ions, should we include the roman numerals indicating the charge of the acid. The solutions manual did not include roman numerals.

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Thank you! My name is not online publicly, is that still okay?

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Is there some place we can check to make sure our chemistry community submissions have been going through every week?

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Are you referring to the problems that take the pH and do calculations with that using log?

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Are there common ions we should know when it comes to naming? and what are they?

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What is the order when it comes to naming?

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What is the gender of Iron Man?
Fe Male

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once i told a chemistry joke...there was no reaction.

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If Avogadro calls tell him to leave his number

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So if double bonds are both sigma and pi bonds, is it in hybridized orbital or between pi orbitals?

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It is simply when an electron goes from a lower to higher energy level. Energy is released (negative).

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What exactly is a nodal plane?

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I would say the elements where the octet rule is strictly enforced is rows 1 & 2 (other than H/He) since rows 3 on have access to d orbital like the above response mentioned.

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The more stable ion is K+ because it has a full shell, thus it is less likely to gain an electron.

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When they ask for the lewis structures, does that refer to all lowest energy resonance structures?

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I'm still confused about the arrangement about the atoms. For examples TB (7th ed) 2C.3c says to draw the lewis structure of HClO3 and I arranged the atoms of oxygen and hydrogen around Cl. The solution manual put the H connected to the Oxygen instead. How would I have known to do this?

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What are the common ions we should know as some of the homework questions do not give us formulas but the name i.e. Draw the Lewish Structure for Chloric Acid

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Does anyone know the difference between lewis structures and complete lewis structures. (7th Edition TB 2B.9)

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H and He are in the 1s shell which only need 2 e- to be a full shell. Li and Be are metals who tend to lose electrons and become the "noble gas" configuration of He (1s shell).

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Formal Charge = [# of valence electrons on atom] – [non-bonded electrons + number of bonds]

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Bonded atoms are more stable than unbonded atoms. For example, in the covalent bond of H2, the electrons from the atoms get to be near 2 protons instead of only the one proton it had initially.

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Does anyone know what information will be given to us...in terms of formulas and what not. Do we need to know the mass of an electron?

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1 joule = 1kg·m^2·s^-2
If you divide it by s-1. One of the 's' cancels out and you get 1kg·m^2·s^-1.

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ATOMIC RADIUS- increases down and to the left
IONIZATION ENERGY & ELECTRON AFFINITY-increases up and to the right
metals are on the left and nonmentals are on the right

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I'm pretty sure that its all the sections under "the quantum world" so 1a, 1b, 1d, 1e, 1f

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Anytime energy is released it is considered negative.

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How often do I tell chemistry jokes? periodically.

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As a side note, the general trend for electron affinity is that it increase upwards and from left to right of the periodic table.

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I have a similar question. Sometimes questions ask for atoms of Cl2. Does this mean the individual atoms (6.02x10^23) or is it referring to the number of Cl2 atoms in a compound like ZnCl2 has 1 atom of Cl2?

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Adding on to what Chathuri said, just because combustion reactions always produce CO2 and H2O, it does not mean it is limited to producing only those compounds. It means it must product those, but if there are other elements involved such as aspartame, N2 is also going to be produced separately.

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Does anyone understand G25? It is about doubling the volume of the solution 90 times.

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