CHEMISTRY COMMUNITY

Khachik_Hmayakyan_2E

If I am not mistaken, the reduction potentials and any other necessary information will be provided on the back of the equation sheet. The equation sheets for each individual exams have been omitted and replaced with a general equation sheet at the beginning of the practice exams section. You can st...

Khachik_Hmayakyan_2E

On page 70 of the introduction to organic chemistry book, why is the compound named 3-chloro-1-ethyl-1-methoxycyclohexane instead of 1-chloro-3-ethyl-3-methoxycyclohexane. Alchabetically the first substituent chloro should get the higher number shouldn't it? Is it because the oxy-substituent is give...

Khachik_Hmayakyan_2E

Question 30 in section 4 states that a reaction will NOT occur at room temperature if the activation energy is 125 kj/mol. What is used to figure out that the reaction will not proceed at 298 kelvin?

Khachik_Hmayakyan_2E

Can heterogeneous catalysts bind to more than one molecules involved in a reaction?
And also, is a catalyzed reaction more exothermic than a non catalyzed reaction?

Khachik_Hmayakyan_2E

In chapter 15 question 15, the questions sets up a direct relationship between the the concentration of the reactants and the rate of production of the products. So the rate law comes out to rate=k[CH3Br][OH] How do we know that the rate is first order? And I'm also curious as to how the rate law wo...

Khachik_Hmayakyan_2E

In part B of question 2&3 of practice midterm 2015, It shows that the delta H of 1 mol of water is 42 kj/mol. But in part C, this calculated value for delta H of water is being used as the delta H for the reaction H(rxn). Why is 42 kj/mol being used for the entire reaction.

Khachik_Hmayakyan_2E

I don't understand why in chapter 14 question 23 part B, a value of 0.92 was used as the cathode and 1.09 as the anode. After separating the equation into its half reaction components (with the electrons added to the reactants side), how do we know which half reaction we have to use as anode and whi...

Khachik_Hmayakyan_2E

When calculating the standard Gibbs free energy of a galvanic cell, I'm confused where we acquire the value for n. I know this is supposed to be the number of electrons transferred, but must we do a full redox and oxidation half reaction balancing procedure in order to attain the number of electrons...

Khachik_Hmayakyan_2E

In question 9.55, we are asked to give delta H, S, and G. When calculating, the answer book shows that the Delta S of formation (Delta S with subscript r) is calculated. But on the bottom, it simply gives the Delta S for the product with the notation being Delta S with a subscript m. What does this ...

Khachik_Hmayakyan_2E

Is there work being done by or on the system if the reaction is sponanteous?

Khachik_Hmayakyan_2E

In order for the heat to be transferred to the water, it must first raise the temperature of the copper. In both cases, we use q=mC[delta]T where we input the mass of the copper kettle (given), the specific heat capacity of copper (table 8.2), and the change in temperature (final T -initia T). Repea...

Khachik_Hmayakyan_2E

Technically speaking, chemistry teaches us that alcohol is a solution... do with that information what you will.

Khachik_Hmayakyan_2E

Suffice it to say that we can call a carbon ring with iron atoms in place of the carbons as a Ferrous wheel?

Sorry for the transition metal pun, Cu in class today!

Khachik_Hmayakyan_2E

The electron would be removed or added in a heterogenous diatomic molecule in the order in which the orbitals are filled. The same order that the electrons are filled (up and to the right) will be used to add the electron in BO- and one will be removed from the last filled orbital in BO+

Khachik_Hmayakyan_2E

Yes. Polydentate ligands can bond to the transition metal at more than one site, therefor a bidentate ligand has two areas on it which can bond to the central transition metal atom. This allows bidentate ligands to be considered as 2 coordination numbers when counting the total number of bonds.

Khachik_Hmayakyan_2E

In some questions it Is asked to write the reaction quotient Q or the equilibrium expression K. The answers for these seem to switch between calculating with the partial pressure P[product]/P[reactant] and calculating with Kc instead without the notation for partial pressure being involved in the eq...

Khachik_Hmayakyan_2E

I don't get why my stomach hurts this bad. Me and my friend went to a bar together after our chemistry midterm, he asked for H2O and I asked for H2O too. It tasted pretty funny though.

Khachik_Hmayakyan_2E

When forming resonance structures, can one resonance structure be a double bond with an oxygen atom and the other resonance structure be a double bond with a nitrogen atom? Or must the resonance structure be with the same elemental species within the molecule?

Khachik_Hmayakyan_2E

Can oxygen have an octet with only a single bond? When drawing a Lewis structure, does it matter which atoms receive lone pairs of electrons so long as the total number of electrons remains constant? I counted the total number of electrons for the atoms that form a compound and kept the total consis...

Khachik_Hmayakyan_2E

The solutions manual gives the following explanation : "A ground state oxygen atom has four electrons in the p-orbitals. This configuration means that as one goes across the periodic table in period 2, oxygen is the first element encountered in which the p-electrons must be paired. This added e...

Khachik_Hmayakyan_2E

My mistake, we get -1,0,1 for an principle quantum number value of 2. So how are these numbers related to px, py, and pz orbitals.

Khachik_Hmayakyan_2E

When finding magnetic quantum number for let's say a principle quantum number n=2, we get m= -2,-1,0,1,2. I'm confused how these values get translated into px, py, pz subshells, since magnetic quantum number describes the different orbitals of a subshell.

Khachik_Hmayakyan_2E

I'm having the exact same problem. I went through the calculation multiple times and consistently end up with 6.4 instead of 3.2. Which is exactly double what the answer should be. I'm confused why the workbook is giving an answer that's half the value I calculated.

Khachik_Hmayakyan_2E

Hi Kelsey, in a previous post a student asked how familiar we should be with naming compounds and Chem_Admin posted stating that we should have a general idea of naming compounds but it will be a topic that we will later be discussing and hopefully mastering (if I'm not mistaken). However, this reso...

Khachik_Hmayakyan_2E

Hi Ashlyn, these pictures have always been helpful to me in clarifying the difference between accuracy and precision. It's a simplified way of discerning between the two and realizing why they are important in calculations. http://www.carolina.com/images/teacher-resources/activities/accuracy-vs-prec...

CHEMISTRY COMMUNITY

Search found 25 matches

Re: 2014 Midterm Question 3

Numbering of Substituents

Section 4 question 30

Heterogenous catalysts

Chapter 15 question 15

Midterm 2015 Q. 2 and 3 part C [ENDORSED]

14.23 Cathode vs Anode differentiation [ENDORSED]

Number of mols to use in the equation [ENDORSED]

Delta S of formation vs Delta S

Spontaneous Reactions

Re: Homework Problem 8.19 and 8.21

Re: Post All Chemistry Jokes Here

Re: Post All Chemistry Jokes Here

Re: Placement of Electrons in Orbitals

Re: Finding Coordination Number and Oxidation State [ENDORSED]

K and Q calculations

Re: Post All Chemistry Jokes Here

Resonance structures [ENDORSED]

Octet rule

Re: Ionization Energy of Oxygen [ENDORSED]

Re: Magnetic Quantum number

Magnetic Quantum number

Re: Uncertainty

Re: Naming Compounds

Re: Accuracy vs Precision [ENDORSED]