CHEMISTRY COMMUNITY

Michelle Pham_3H

The moles of iodine is in a solid state, so it wouldn't be included when determining which side has more moles of gas.

Michelle Pham_3H

Hi! During last night's review session, there was a True/False question that stated "For a given reaction, changing temperature is the only way to change K" (#41). The answer was true. If you lower the activation energy, does that in turn change the temperature of the system? I'm just a bi...

Michelle Pham_3H

This is really helpful, thank you!!

Michelle Pham_3H

I understand that these terms have different and complimentary definitions, but is there any easy way to remember which is which? I keep mixing them up and it would be nice to have a mnemonic device or something to distinguish them from each other. Thanks in advance! Lewis acid = electron acceptor L...

Michelle Pham_3H

Increasing the amount of oxygen atoms also increases the oxidation state and the electronegativity of the compound. The oxygen atoms pull electron density towards themselves, weakening the O-H bonds. This makes it easier for the H+ to ionize in water, making the acid stronger. Overall, adding oxygen...

Michelle Pham_3H

To add on to what was said earlier, Q is the ratio of the products to reactants in a given instant, while K is this ratio at equilibrium.

Michelle Pham_3H

Today in lecture, we discussed a lot of conceptual ideas regarding the response of equilibria to change and Le Chatelier's principle. Professor asked a question that I didn't catch the answer to. If someone could explain and answer this question I would really appreciate it: Without adding more reac...

Michelle Pham_3H

The concentration is equal to n/v since it is moles of substance over its volume. So when you rearrange the equation from PV = nRT, n/V = P/RT. n is the moles of gas, V is the volume of gas, P is is the pressure of the gas, R is the gas constant, and T is the absolute temperature of the gas.

Michelle Pham_3H

Today in lecture we discussed how one would calculate equilibrium concentrations using x in the ICE box when the change in concentration is unknown. The example given had one negative and one positive value, and professor also addressed that one value would be too large if both were positive. When c...

Michelle Pham_3H

I think it is asking if you would expect the bond angle to increase from 109.5 (sp^3) to 120 (sp^2) degrees when the ratio of s increases between these hydridized orbitals.

Michelle Pham_3H

I am a bit confused about where this value came from. Was it just calculated and given to us, or are we able to determine this value ourselves? Thanks in advance!

Michelle Pham_3H

In Test 3, there was a question that asked us to put several elements in order of decreasing electron affinity. Using the general guideline that electron affinity increases across a period and decreases down a group, I put P, Na, and Ar into the order Ar, P, and Na. The correct answer was P, Na, Ar....

Michelle Pham_3H

Today in lecture, we discussed the Lewis structure for xenon tetrafluoride and how it can accommodate 12 electrons (4 single bonds, 2 lone pairs). Based on what we have learned, we know that S, P, and Cl can have more than an octet. Why can xenon have more than an octet, and are there any other simi...

Michelle Pham_3H

We discussed in lecture how P, S, and CL can all have expanded octets due to their size and vacant d-orbitals. Is there a maximum amount of electrons that their expanded octets can accommodate? And if not, would we just draw our Lewis structures according to formal charge and knowledge that these el...

Michelle Pham_3H

At the review sessions today, all of the examples done were covalent molecules/compounds. I know that there were several examples in the textbook and in class that were done with brackets. Would those all be considered ionic, and if so would you just use electronegativity trends to determine whether...

Michelle Pham_3H

I think I need to refresh my memory on periodic table trends. I'm familiar with the inert gases and alkali metals, but how can you determine which category (metal, nonmetal, semimetal/metalloid) an element falls into just by looking at the periodic table? Thanks in advance!

Michelle Pham_3H

We've started drawing Lewis structures based on our knowledge of electron configurations, and while I'm clear on how many valence electrons s- and p- block elements normally have, is it the same for d-block elements or is that given? Any examples would help too. Thanks in advance!

Michelle Pham_3H

For Question 2.25, it asks you how many electrons can occupy the given orbitals of an atom: a) 4p-orbitals = 6 electrons (one pair each for px,py,pz) b) 3d-orbitals = 10 electrons (one pair in each of the five orbitals) c) 3s-orbitals = 2 electrons (one pair in one orbital) d) 4f-orbitals = 14 elect...

Michelle Pham_3H

I know we discussed the different p orbitals (px, py, and pz) in class, but are there different ones for d and f as well? If so, what are the different notations for these orbitals? I didn't get this far in high school chemistry, so I was a bit lost last lecture. Any explanation is greatly appreciat...

Michelle Pham_3H

I noticed that for the questions that pertain to the DeBrogile Equation, kilograms is used to measure mass as part of momentum. For example, in problem 1.39 the mass of the baseball in ounces had to be converted to kilograms. So unless the problem is asking for grams of substance, should I assume th...

Michelle Pham_3H

So I'm understanding the general concepts we have been discussing during lecture and the problems we have been practicing, but I'm kind of confused with what exactly a photon is. I know it's a particle that makes up all kinds of light, but if you had to define it in succinct terms without missing an...

Michelle Pham_3H

Thanks everyone!

Michelle Pham_3H

Hi! I'm still trying to wrap my head around why we were told to round to the nearest even number when the number immediately after the last significant figure is 5. In my high school chemistry class this was never discussed, not to say that high school chemistry is that advanced, but this is still a...

Michelle Pham_3H

This only answers your question in regards to combustion. In a combustion reaction, oxygen is always part of the reactants, while water and carbon dioxide are always given off as products. All three are normally in the form of a gas. Combustion reactions are often indicated through burning, metaboli...

Michelle Pham_3H

One way that I remember metric prefixes is kind of antiquated and silly, but I learned it in middle school and I still use it now. It's an acronym called "King Henry Dances Up Down Chocolate Mountain", and it gives you the order of the metric prefixes from largest to smallest (kilo-, hecto...

Michelle Pham_3H

Before rounding off the number to two significant figures (given by 0.20M copper sulfate), I got 12.48446 grams which is very close to your answer.

CHEMISTRY COMMUNITY

Search found 26 matches

Re: Practice Test Fall 2017 [ENDORSED]

Re: Chemical Equilibrium True/False

Re: Lewis v. Bronsted Acids/Bases

Lewis v. Bronsted Acids/Bases

Re: Comparing Strengths of acid from structure/formula

Re: Q [ENDORSED]

Concept Question

Re: Gas concentration

Calculating Equilibrium Composition [ENDORSED]

Re: 4.43

109.5 degrees

Electron Affinity - P, Na, Ar

Noble gas exception

Expanded Octet Max

Lewis Structure Format

Metals, Nonmetals, and Semimetals/Metalloids

Determining valence electrons for d-block elements [ENDORSED]

Re: Chapter 2 #25 and #29 [ENDORSED]

Different d and f orbitals

Units for Mass [ENDORSED]

Photons

Re: Rounding Rule for 5

Rounding Rule for 5

Re: What’s the quickest way to approaching writing a balanced equation with only one given compound?

Re: Do we need to memorize unit conversions? [ENDORSED]

Re: G17