CHEMISTRY COMMUNITY

Jamie Hsu

I asked a TA and they said that it would be helpful and we should memorize them

Jamie Hsu

Why does KBr have a pH that equals 7?

Jamie Hsu

You should take the negative log of the H3O+ concentration so the answer is actually -(-.176) which is simplified to +.176

Jamie Hsu

I am not sure how to find the coordination number, however the coordination number is defined as the number of atoms or ions immediately surrounding a central atom in a complex.

Jamie Hsu

I had the same question too. I am a bit confused because we hadn't gone over the chart in class so I'm not sure to what extent we should memorize the chart

Jamie Hsu

According to the book definition, a chelate is a complex containing one or more ligands that form a ring of atoms that includes the central metal atom.

Jamie Hsu

When determining the location of a lone pair on the central atom, does it matter between which elements the lone pair is placed in? For example in the 7th edition number 2E.23c we have IO2F2- We have iodine as the central atom and have Fluorine on the south and west end of Iodine and Oxygen to be on...

Jamie Hsu

For the 7th Edition number 2F.15, what does it mean when it talks about the s character of hybrids? What is the s character of a hybrid and how can it increase?

Jamie Hsu

Lone pairs on non central atoms should not affect the shape of the molecule

Jamie Hsu

I think CBr4 only has London forces because it is a non polar molecule. London forces are always present so CBr4 only has London forces.

Jamie Hsu

We should be able to identify bond angles whether it be for example 180,120, 90 or <120,<90
However we do not need to know the specific bond angle for a specific molecule if it is less than like <120 because the bond angle would vary slightly for each molecule.

Jamie Hsu

Yes, a single/double/triple bond is considered just 1 region of electron density. A lone pair is considered 1 region of electron density as well

Jamie Hsu

I think oxygen is more electronegative than chlorine because it is on the same period as fluorine. Even though the electronegativity decreases going both down a group and to the left of a period, there is a greater change in electronegativity between periods than groups. (If two elements are placed ...

Jamie Hsu

I don't think there are certain "tricks" in drawing resonance structures. The best way would be to look at the formal charges and making sure they are as close to zero (or add up to the ion charge) If the structure consists of different types of bonds and you notice that the different type...

Jamie Hsu

Trends are generally helpful as they give us useful information when drawing Lewis Structures. For example, the electronegativity trend can give us a good idea as to what element to put in the center because we want the least electronegative element in the center.

Jamie Hsu

If we are comparing the radius of an atom on the very right side of the periodic table (group 17, period 3) with an atom on the left side of the periodic table (group 2, period 4) how should we compare the size of the atomic radius if they are in different groups and their periods are next to each o...

Jamie Hsu

For 7th edition, chapter 2C number 5C, why is the Lewis structure not a resonance structure if the two oxygens that are attached to the nitrogen are 1 single bond and 1 double bond?

Jamie Hsu

On the 7th edition for chapter 2c number 5A, why is the unpaired electron on chlorine as opposed to having it on oxygen?

Jamie Hsu

Could someone explain why in 2.B.9 in the 7th edition, the Lewis structure for potassium phosphide has the P in the center with 8 electrons, and the K does not have any electrons and isn't attached to the P, but instead just floats around the P?

Jamie Hsu

n=2 can either be the 2s or 2p subshell. The 2s subshell has 1 orbital while the 2p subshell has 3 orbitals. Since it asks for the general principal quantum number of n=2, we must take into account 2s and 2p so we add 1 orbital + 3 orbitals to get 4 possible orbitals.

Jamie Hsu

Use the DeBroglie wavelength equation and plug into the numerator Planck's constant. In the denominator you can multiply the mass of an electron (9.11x10^-31 kg) by the velocity which is 3.6x10^6 ms-1. This should give you the desired answer of 2.02 x 10^-10 meters.

Jamie Hsu

Helium is part of the s block, not the p block. The electron configuration is 1s2, so even though it does appear on top of the p block when looking at the periodic table, it still belongs to the s block.

Jamie Hsu

When coming across the homework, I noticed one of the problems mentioned something about the g orbital. Does anyone know what the g orbital is and if it is ever used in writing ground state electron configuration?

Jamie Hsu

When we are given 5d, 1s, 6f, 2p, I usually like to first identify where that shell/subshell is on the periodic table. Typically when you are looking at the s shell, it has 1 orbital, the p shell has 3 orbitals, the d shell has 5 orbitals, and the f shell has 7 orbitals.

Jamie Hsu

I don't think you can calculate the mass of light. We are given the speed of light which is the constant c=2.99792x10^8 ms^-1, but the mass of light is I believe negligible as someone has already said.

Jamie Hsu

In our summary notes, I am reviewing how "in the photoelectric experiment, light sources with long wavelength light cannot eject electrons." Can someone please clarify why this is the case?

Jamie Hsu

yes, because in the equation E=hv, h is a constant. So as the frequency increases, the energy too should increase as well

Jamie Hsu

^ I agree. I think we should have a general idea and be familiar with the spectrum, however knowing the exact numbers may not be necessary. But it can never hurt to memorize it!

Jamie Hsu

For question F.15 from the problem sets, I noticed that when calculating the number of mols of H, the setup is 4.60gH/1.008g mol-1 According to the sig fig rules 4.60 has 3 sig figs and 1.008 has 4 sig figs, and when dividing we should take the lowest number of sig figs, however the answer is 4.563 ...

Jamie Hsu

For question F.17 on the problem sets, what is the difference between formula mass and molar mass?

Jamie Hsu

When dividing by the smallest value in solving for the empirical formula, you should usually get a whole number or a number very close to a whole number. In the instances where you get ".99 or .97", I would say rounding up to get the ratios would be appropriate. However if you calculate a ...

CHEMISTRY COMMUNITY

Search found 31 matches

Re: Memorize strong and weak acids and bases?

7th Edition 6D11

Re: 7th Edition Problem 6B.9 Solution

Re: Coordination Number

Re: Common Ligand Names

Re: Chelate

Determining Location of Lone Pair

7th Edition 2F.15

Re: lone pairs

Re: 6.1 Sixth Edition Intermolecular Forces

Re: Bond Angles

Re: Multiple bonds

Re: Electronegativity

Re: Finding all Resonance Structures

Re: What are the trends useful for?

Atomis Radius Trend

7th Edition 2C5.C

7th Edition 2C5.A

7th Edition 2.B.9

Re: 1D.23, part c (7th Edition)

Re: Question 1.B.15 7th

Re: Helium

G Orbital

Re: 7th Edition HW 1D.21

Re: Mass of Light

Summary Notes Clarification

Re: Energy per photon equation

Re: Do I need to memorize the Light Spectrum? [ENDORSED]

F.15

Formula Mass and Molar Mass

Re: Empirical Formula Calculations