Search found 19 matches

by sandros
Sat Dec 09, 2017 1:39 am
Forum: Ionic & Covalent Bonds
Topic: Ionic Character
Replies: 2
Views: 245

Re: Ionic Character

Because the electronegativity diffrence between C and O is greater than between C and S
by sandros
Thu Dec 07, 2017 6:45 pm
Forum: Naming
Topic: Exception ?
Replies: 1
Views: 238

Exception ?

I was going through the chapter in the book and one example kind of confused me. [ Fe ( N CS)(OH2)5 ] 2+ I thought that the name of this complex would be pentaaquathiocyanato(kN)iron (III) ion However the correction states that the name of this complex is: thiocyanato(kN)pentaaqua(III) iron I have t...
by sandros
Thu Dec 07, 2017 2:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.19 c)
Replies: 1
Views: 201

4.19 c)

In this exercise they asked to predict the shape and estimate the bond angle of BH2 - (2 H atoms and a -1 negative charge) When drawing its Lewis structure something came to me and I asked myself why isn't it a biradical ? I mean at first it seems logical that it would have a bent shape but then I r...
by sandros
Sun Dec 03, 2017 5:20 pm
Forum: Bronsted Acids & Bases
Topic: 12.1
Replies: 2
Views: 194

12.1

When writing conjugate acids and bases is there any difference between a specific writing form or another? For example, when asked to write the conjugate acid of CH3NH2 is there a difference between CH3NH3+ and CH4NH2+ or even CH6N+ ? If yes then how do we know which one is correct ?
by sandros
Tue Nov 28, 2017 11:56 pm
Forum: Naming
Topic: Polydentate
Replies: 3
Views: 265

Re: Polydentate

I think we have to memorize which ligands are polydentates and the # of bonds they can make with the TM. Take a look at table 17.4 there are a few we have to memorize I guess.
by sandros
Tue Nov 28, 2017 11:53 pm
Forum: Naming
Topic: 17.33 (a)
Replies: 2
Views: 220

Re: 17.33 (a)

Take a look at table 17.4 it says that NH2CH2CH2NHCH2CH2NH2 (diethylenetriamine) is a tridentate.
by sandros
Sun Nov 26, 2017 9:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Chapter 4
Replies: 1
Views: 144

Chapter 4

The syllabus says we only have parts 4.1 to 4.7 but I'm not really sure whether we have to study everything or just up to 4.7
Does anyone know for sure ?
by sandros
Tue Nov 07, 2017 11:33 pm
Forum: Lewis Structures
Topic: 3.67B and Radicals
Replies: 2
Views: 219

Re: 3.67B and Radicals

A radical has an odd number of electrons which leads to its unpaired electron. Therefore, anytime you count the electrons and obtain an odd number, then you can conclude that it is a radical. Hope this answers your question.
by sandros
Tue Nov 07, 2017 3:19 pm
Forum: Octet Exceptions
Topic: Beryllium exception
Replies: 4
Views: 715

Re: Beryllium exception

Beryllium and lithium both form a duplet instead of forming an octet. This is mainly related to the fact that the energy required to give Li and Be a full octet is much higher than the energy required to give up one or two electrons and form a duplet (the same way as helium does).
by sandros
Mon Nov 06, 2017 9:40 pm
Forum: Empirical & Molecular Formulas
Topic: Post-Module Assess. #14
Replies: 2
Views: 273

Re: Post-Module Assess. #14

First you find the mass percentage of each element given that you already have the total mass Then you imagine that the sample mass is 100g and you can then transform your percentages into actual masses (in grams) Once you transform these percentages, you divide the mass of each atom by its molar ma...
by sandros
Sun Nov 05, 2017 7:43 pm
Forum: Ionic & Covalent Bonds
Topic: 3.25
Replies: 6
Views: 507

3.25

Can someone please explain the process ? I can't figure out the correct answers for that one ...
by sandros
Sun Nov 05, 2017 3:32 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Formal charge and lewis structures
Replies: 5
Views: 348

Re: Formal charge and lewis structures

I feel like it depends on the question that is asked. If the question lacks precision, I'd go with the most obvious one for sure.
by sandros
Mon Oct 30, 2017 10:26 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: H-Bar vs h
Replies: 2
Views: 445

Re: H-Bar vs h

H-bar is just h divided by 2pi.
Since h= 6.626 x 10^-34
h-bar would be equal to (6.626 x 10^-34) / 2pi = 1.054 x 10^-34
by sandros
Mon Oct 30, 2017 1:38 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Chapter 1 #57 [ENDORSED]
Replies: 2
Views: 409

Re: Chapter 1 #57 [ENDORSED]

You know that for the Balmer series, n1=2 and you have the wavelength of the last spectral line so if you plug in all your variables into Rydberg's formula you'll be able to get the n2 for the last line. The next line in the series corresponds to a transition from n1=2 to n2= whatever you got from y...
by sandros
Mon Oct 30, 2017 1:26 am
Forum: Quantum Numbers and The H-Atom
Topic: Unpaired electrons (Homework 2.51) [ENDORSED]
Replies: 3
Views: 1242

Re: Unpaired electrons (Homework 2.51) [ENDORSED]

According to Hund's rule, orbitals of the same energy are each filled with one electron before filling any with a second. Also, these first electrons have the same spin. (wikibooks.org) Since we have 5 different orbitals for d then we can have up to 5 unpaired electrons. Therefore, the correct answe...
by sandros
Sat Oct 14, 2017 6:18 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Confused about hw question 1.15 [ENDORSED]
Replies: 1
Views: 213

Re: Confused about hw question 1.15 [ENDORSED]

In order for you to solve this problem, you should know that the U.V spectrum of H-atom corresponds to the Lyman series. Also, for the Lyman series, n1=1. To start off, you can calculate the frequency by using the following formula : c= frequency x wavelength. Once you calculate the frequency, you c...
by sandros
Sat Oct 14, 2017 6:10 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1.57 [ENDORSED]
Replies: 1
Views: 174

Re: 1.57 [ENDORSED]

For the Balmer series, we know that n1=2. We also know that the difference between two energy levels is emitted as a radiation of a particular wavelength. This is called a spectral line. Therefore, the difference between E3 and E2 gives us the first spectral line of the Balmer series. As we go on, E...
by sandros
Fri Oct 06, 2017 3:14 pm
Forum: Empirical & Molecular Formulas
Topic: Friday Oct 6 Test
Replies: 7
Views: 691

Friday Oct 6 Test

Concerning the test we've had today, we were asked in question 6 to find the molecular formula of a compound X that has a MM= 46g.mol-1. They also gave us the mass of the compound and the mass of the products. They mentioned that the reaction was a combustion and that X was only made of the elements...
by sandros
Fri Oct 06, 2017 2:58 pm
Forum: Balancing Chemical Reactions
Topic: Equation Notation [ENDORSED]
Replies: 2
Views: 242

Re: Equation Notation [ENDORSED]

Usually, when you use subscripts, you refer to the element that precedes it. For example: C6H12O6 implies that there are 6C, 12H and 6O in this compound). However, when you use parentheses, the subscript refers to all the elements inside the parentheses. For example, Si(HCO3)4 implies that there are...

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