CHEMISTRY COMMUNITY

Kim Vu 2G

For question 6a, why isn't it considered a trans/cis molecule since it has a double bond and the methyl group is on the opposite side of the ch2 so wouldn't it be E?

Kim Vu 2G

When naming organic molecules, why does the alkene get numbering priority before the alkyne?

Kim Vu 2G

For amines, in the course reader, it says that an R group connected to NH2 is a primary structure, so type would CH3CH2NH3(ethyl ammine) be? And just for clarification, is the ammine group always N connected to one or more C?

Kim Vu 2G

Can you determine trans and cis geometric isomers just by using the line structure, if so, how would you do that? or would you have to draw out the lewis structure?

Kim Vu 2G

NO2 is an intermediate because by definition, an intermediate is a substance that is produced in one step and then used up in another step of the reaction mechanism. NO2 here matches this definition as it is produced in the first step and then used up in the second step. NO however is a catalyst bec...

Kim Vu 2G

For the midterm, I did not add a phase change because the substance was not water and so you wouldn't be able to know the enthalpy of fusion since it was not given. It depends on how much temperature the change is say water going from -10 to 110 degrees Celsius, there are going to be phase changes f...

Kim Vu 2G

yes you multiply two to Rb because you have to balance the charges of the electrons from F2+2e--->2F, so that the electrons cancel out and you are left with a balanced equationl of F2+2Rb--->2F- + 2Rb+

Kim Vu 2G

I have used both equations too and have received the same answers for both,which you should have but I don't you will be marked off if you used the logQ equation because essentially it should lead you to the answer unless on the midterm it says specifically to use the nernst equation in the ln form.

Kim Vu 2G

I have a follow up question to this problem. So I noticed that in the solution's manual, there is no presence of Cl anywhere in the reaction. Is this because the Cl has completely dissociated due to the acidity of the reaction?

Kim Vu 2G

it is important to determine the anode and cathode because when you are writing the galvanic cell, it is easiest to write the diagram flowing from anode to cathode as the book and the solution's manual does it, and theres not really a trick but when you write out the half reactions, the side with th...

Kim Vu 2G

you don't multiply the value of the e cell because the E represents the cell's potential under standard conditions being at 25 C, 1 atm, and one mole and so even if you multiply and change the amount of moles, the value of the e cell would still wouldn't change and this isn't like hess's law where y...

Kim Vu 2G

c. Cd(s)+2Ni(OH)3(s)--->Cd(OH)2(S)+2Ni(OH)2 I have a question with writing the galvanic cell diagram because I found the half reaction correctly just like the course reader but for the galvanic cell, the course reader had Koh(aq) on the anode side. I was wondering why Koh is needed and why is it the...

Kim Vu 2G

For #6, What mass of propane, C3H8, must be burned to supply 2580 kJ of heat? The standard enthalpy of combustion of propane at 298K is -2220kJ/mol. I'm not sure how to approach this problem after writing out the combustion reaction.

Kim Vu 2G

I understand the calculations here, but just a general question to find the degeneracy. Do you just have to manually draw all the lewis structures for the molecule to find the degeneracy or is there another way?

Kim Vu 2G

Calculate the heat released by 5.025g of Kr at .4 atm as it cools from 97.6 degrees to 25 degrees at a)constant pressure, b)constant volume. Assume that krypton behaves as an ideal gas. For part a, why is the molar heat capacity 10.8J/mol*C and part b 12.5 J/mol*C? Does it have to do with ratio of s...

Kim Vu 2G

Why is it that when the temperature increases in an enthalpy problem, it is an exothermic reaction instead of endothermic?Wouldn't the increase from initial to final temperature make the system endothermic because heat is being absorbed by the system?

Kim Vu 2G

open system is when energy and matter of the system is exchanged with the surroundings. A closed system is when there is a fixed amount of matter in the system but still can exchange energy with its surrounding and an isolated system is when the system has no contact or exchange with its surrounding...

Kim Vu 2G

if you add up all the electrons from argon plus 4 from the 3d, you should have 22 electrons leaving you at Titanium. With a metal with a cation of 2+ that means that 2 electrons have previously been subtracted away from it leaving it with titanium with 2 less electrons. So to find the original state...

Kim Vu 2G

For homework question 11.67."The reaction 2HCL<->H2 + Cl2 has K=3.2 x 10^-34 at 298 K. The initial partial pressures are H2, 1 bar; HCl 2 bar and Cl2 at 3 bar at equilibrium there is 1 mol H2. What is the volume of the container?" Why is there a new initial state of pressure in this equati...

Kim Vu 2G

For pentaamminechloronickel (III) chloride, both of the formulas of [Ni(NH3)5Cl]Cl2 and [NiCl(NH3)5]Cl2 work and for the naming ligand, the letter a in ammine comes before the letter c in chloro so ammine gets named before chloro.

Kim Vu 2G

I think its just helpful to know the Lewis structure because to figure out the binding of the ligand to the central atom, you need to know how many lone pairs and bond pairs it has to be available for binding. When a ligand is bidentate, it means that they have two donor atoms which allow them to bi...

Kim Vu 2G

If it does not obey the octet rule, it can have more than 8 electrons on the central atom depending on the element because some transition metals can have up to 18 electrons because of the extra shells that can be filled in the d block so it just really depends on the atom itself.

Kim Vu 2G

Yes, groups 17 atoms can form double and triple bonds, depending on the element it is bonding with. Iodine only needs one more valence electron to complete its octet, however, it has the ability to expand its octet so it is possible for Iodine to have more than a single bond. I believe all group 17 ...

Kim Vu 2G

An ionic bond is usually between a metal and non-metal, where the negatively charged element with the higher ionization energy would attract the positively charged to form an octet in its valence electron. Covalent bonds are usually bonds between nonmetals in which the elements share valence electro...

Kim Vu 2G

For bent, AX2E2, the bond angle is <109.5. The bond angles of seesaw would be less than 120 and 90 degrees, not 180 degrees and yes the lone pair does have a stronger repulsion than the bond pair, which is why the the angles are less than 120 and 90 degrees.

Kim Vu 2G

a) the electrons in the element Argon equals 18 and adding 6 more electrons from 3d^6 would make it 24 electrons, which would be chromium. However, the question is looking for a metal with 3+ ion which is means that 3 electrons were reduced from it already, so to find the element, you would add 3 mo...

Kim Vu 2G

The answers in the workbook is telling you to use the Bohr equation which is En=-2.18*10^18 (z^2/n^2). The 2.18*10^18 is just a constant for the equation, the z is for the number of protons in the nucleus and n is the quantum level. Because the frequency was given, you can use it to find the change ...

Kim Vu 2G

The problem says, calculate the wavelength of light emitted when an electron in a hydrogen atom makes the transition from n=5 to n=3. How would you solve this equation? Using En= -hR/n^2 or v=R(1/n1 ^1) - (1/n2^2)?

CHEMISTRY COMMUNITY

Search found 28 matches

Final 2013

Alkene and Alkyne

Amines

Trans and Cis

Re: Difference between catalysts and intermediates

Re: Phase Change and Enthalpy

Re: 2011 midterm Q6 B

Re: logQ vs lnQ

Re: 14.17 textbook problem

Re: Anode and Cathode

Re: Standard reduction potentials

homework 14.15

Quiz 1 Prep

Re: Determining Residual Entropy in Crystal Form

8.31 heat released by Krypton gas

Exothermic reaction

Re: Open, Closed, or Isolated Systems

Re: Final 2010 Q3A

Equilibruim

Re: Writing coordination compound formulas

Re: Polydentate Using Lewis Structures

Re: Octet Rule

Re: Double bonds on group 17 atoms

Re: Covalent and Ionic Bonds

Re: Bond angles of atoms with lone pair electrons

Re: Ground-State Electron Configurations of Ions 3.11

Re: Fall 2014 Quiz 1 Preparation

Rydberg's Equation