CHEMISTRY COMMUNITY

Navarro_Bree_1D

Dear Dr. Lavelle, Thank you for your dedication and passion towards this course and your students. I've had the highest pleasure of being in your class for 14A and 14B. You are one of the best professors I've ever had at UCLA. You provide us with more than enough resources to succeed. You will be de...

Navarro_Bree_1D

The standard enthalpy of activation will always be positive because bonds are being distorted and extended. Activation energy = Standard enthalpy of activation + RT. As we can see from the equation above, the barrier to the transition state is an enthalpic one, that is why the standard enthalpy of a...

Navarro_Bree_1D

The central N atom has 4 electrons than its usual 5. That's why there is a positive charge on it

Navarro_Bree_1D

Pentyl is the IUPAC naming and amyl is the common naming

Navarro_Bree_1D

To answer your question, Caleb, you treat halogens the same way you treat substituents on an alkane chain/ring. The halogen has equal rank as any other substituent.

Ex//: CH3CHClCH2CH3 --> 2-chlorobutane

(More examples on page 93 of the Course Reader)

Navarro_Bree_1D

I would like to add that free energy of activation and activation energy have very similar values, but they are not exactly equal. Free energy of activation is more accurate than activation energy because free energy of activation includes both the standard enthalpy of activation and the standard en...

Navarro_Bree_1D

Here is a youtube video that goes over the difference between thermodynamic and kinetic control.

https://www.youtube.com/watch?v=l-l_8cSQdEw

Navarro_Bree_1D

Residual and positional entropy are the same thing. I would like to add that molar residual entropy is different than residual/positional entropy. When determining the degeneracy of molar residual entropy, the exponent used in Avogadro's constant. This makes sense because molar residual entropy repr...

Navarro_Bree_1D

The value of n is determined by the number of electrons needed to balance the two half reactions. For the half reaction with Mn2+, there are 5 electrons. For the half reaction with Br2, there are 2 electron. In order to balance the overall equation, you need to multiply the half reaction with Mn2+ b...

Navarro_Bree_1D

It is important to know that enthalpy (delta H) is the amount of heat released/absorbed at constant pressure. Without constant pressure, it is just heat, not enthalpy.

Navarro_Bree_1D

From the reaction: Br2(l) --> Br2(g), you know you are starting with a liquid and ending with a gas. When T>333K, the temp is high enough to make the reaction spontaneous. Therefore the reaction is considered "gas phase only" because all of the liquid Br2 is becoming gaseous Br2. When T<33...

Navarro_Bree_1D

You are given the following: OF2(g) + H2O(g) --> O2(g) + 2HF(g) Delta H = -318 kJ What is the change in internal energy for the reaction of 1.00 mol OF2? We need to use PV=nRT but there is no T given and this delta H is not the standard reaction enthalpy. Yet the solution uses 25 degrees Celsius. Ho...

Navarro_Bree_1D

Although these heat equations look very similar, they are quite different. 1. Qp=n*Cp*change in temperature 2. Q=(mass)*Csp*change in temperature For the first equation, -heat is at constant pressure -n = # of moles -Cp = molar heat capacity at constant pressure (kJ/C mol) -you use moles to cancel o...

Navarro_Bree_1D

I also had a question about this too. For part e and part f, why do you attach 6 molecules of water to the transition metal?

Navarro_Bree_1D

Which homework question are you referring to specifically?

I am pretty sure you just add H^+ to the end of the compound. So it would be NH2NH3^+

Navarro_Bree_1D

Here is a general rule of thumb when determining the relative strength of acids: 1. Is the acid organic or inorganic? --Organic acids (compounds with carbon) are usually weaker than inorganic acids (compounds WITHOUT carbon) **NOTE: Acids can be modified to be stronger** 2. What elements make up the...

Navarro_Bree_1D

The answers for your question can be found in the course reader, on page 139. (-: If a reaction is exothermic while forming products, then heating will favor the formation of reactants. (shift to the left) If a reaction is endothermic while forming products, then heating will favor the formation of ...

Navarro_Bree_1D

For the quiz, my TA said we need to know how to name cis and trans from a diagram or draw a structure from the name given (cis or trans). I don't think we will have to know if the compound is cis or trans when the only information given is the elements. If you want to make sure, I would go to Profes...

Navarro_Bree_1D

This problem wants to know which gases contribute to global warming. Gases with dipole moments contribute to global warming. These dipole moments do not have to occur in the most stable form of the gas. The Lewis structure of SO2 with a single bond and double bond is a better representation for this...

Navarro_Bree_1D

In addition, you must remove an electron from the orbital with the highest energy level because these electrons are the easiest to remove compared to the electrons from orbitals with lower energy levels. The electron configuration of Cl is [Ne]3s^2 3p^5. --The highest energy level is 3p. --Therefore...

Navarro_Bree_1D

3.39 Write the complete Lewis structure for each of the following compounds: (a) ammonium chloride (b) potassium phosphide (c) sodium hypochlorite I am confused on how to draw Lewis Structures for ionic compounds that also have covalent bonds. In the solutions manual, they put brackets around NH4, P...

Navarro_Bree_1D

According to the website, "Fermilab Today," at the quantum scale, space never has zero energy because electrons have both particle-like and wave-like properties. Their constant movement can be measured in kinetic energy. From my understanding, I think a particle in a container cannot have ...

Navarro_Bree_1D

Example: The speed of an electron emitted from the surface of a sample of Potassium by a photon is 668km/s. Its work function is 2.29 eV. - What is the wavelength of the radiation that caused photo-ejection of the electron? In the textbook, they convert the work function from electron-volts to joule...

Navarro_Bree_1D

I think the equation does not include rotational energy because rotational energy at the atomic level is not significant enough to take into account. The moment of inertia is extremely small.

CHEMISTRY COMMUNITY

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Re: Saying Thank You to Dr. Lavelle

Re: Question 4.37

Re: Thiocyanate Lewis Structure [ENDORSED]

Re: Naming [ENDORSED]

Re: Naming Organic Molecules

Re: Free energy of activation vs. activation energy

Re: Homework 15.79

Re: Thermodynamics

Re: Question 7 2013 Midterm

Re: Entropy vs Enthalpy

Re: Gas Phase Only vs Liquid Phase Only

Chapter 8.49

Re: Calculating Heat Required

Re: Homework Help 12.65

Re: Naming conjugate acids

Re: Strong Acid or Weak Acid

Re: Equilibrium Shifts

Re: cis/trans naming

Re: Fall 2012 Midterm Q5B

Re: Chapter 3 Homework #13

Lewis Structure Problem 3.39 [ENDORSED]

Re: Why can't a particle in a container have zero energy?

Textbook Example 1.5 Analyzing the Photoelectric Effect [ENDORSED]

Re: Kinetic Energy