Search found 30 matches

by Bingcui Guo
Fri Dec 07, 2018 3:33 pm
Forum: Bronsted Acids & Bases
Topic: 6C.17 (7th edition)
Replies: 2
Views: 84

Re: 6C.17 (7th edition)

generally, the strength of an inorganic base is stronger than an organic base. So you can just write out BrO- is more basic than C17H19O3N.
by Bingcui Guo
Fri Dec 07, 2018 3:29 pm
Forum: Bronsted Acids & Bases
Topic: Problem J.7 - 7th Ed.
Replies: 4
Views: 111

Re: Problem J.7 - 7th Ed.

The anion of the product is from the acid and cation of the product is from the base. The base is the cation with an OH- and the acid is a anion with a H+. So that you can write out the reactants and balance the equation.
by Bingcui Guo
Fri Dec 07, 2018 3:19 pm
Forum: Lewis Acids & Bases
Topic: 6.5 (7th edition)
Replies: 1
Views: 49

Re: 6.5 (7th edition)

In Lewis acid and base theory, all the base are electron donors and all the acid are electron acceptors. They do not need to be in aqueous state, they can be either states, either gas, solid, liquid. And in this question, you can think of H2O2 to split into 2 OH one with the electron lone pair the o...
by Bingcui Guo
Fri Nov 30, 2018 1:46 pm
Forum: Lewis Acids & Bases
Topic: HI or HCl: stronger acid
Replies: 8
Views: 491

Re: HI or HCl: stronger acid

How to define strong acid and weak acid depends on the easiness to lose an electron. Since the bond of H and I is easier to break than H and Cl, it is easier for HI to lose H+ and thus it is a stronger acid than HCl.
by Bingcui Guo
Fri Nov 30, 2018 1:43 pm
Forum: Bronsted Acids & Bases
Topic: J15
Replies: 2
Views: 80

Re: J15

C6H5OH(aq) + H2O(l) <--> C6H5O-(aq) + H3O+(aq)
The essence is to treat H+ as a proton and form H30+
by Bingcui Guo
Fri Nov 30, 2018 12:14 pm
Forum: Lewis Acids & Bases
Topic: HF
Replies: 5
Views: 118

Re: HF

F's electronegativity is so strong that it is hard for it to fully release the H+. So it is hard to break the bond between H and F thus HF is a weak acid. But remember, HCl, HBr, HI are all strong acids.
by Bingcui Guo
Tue Nov 20, 2018 10:31 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Sigma and Pi Bonds
Replies: 5
Views: 119

Re: Sigma and Pi Bonds

A single bond is always sigma bond since only s to s or p to p. But for double bond, the px to px is fixed, and the py and py, pz and pz are parallel side by side and they can form a sigma bond and pi bind.
by Bingcui Guo
Tue Nov 20, 2018 10:06 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 3
Views: 59

Re: Bond Angles

I think the answer means that all the angles of this compound is the same, cuz the two Cl atoms are the same.
by Bingcui Guo
Tue Nov 20, 2018 10:02 am
Forum: Hybridization
Topic: Ethene (C2H4) hybridization
Replies: 2
Views: 96

Re: Ethene (C2H4) hybridization

Because the valance electron of carbon atom is four so it originally has 2 in 2s and 2 in sp. The two 2s's energy becomes higher and combine with one electron in p orbital to become sp2 and the left p electron is itself an orbital. You can regard sp2 as 3 orbitals and p as one orbital, with one elec...
by Bingcui Guo
Thu Nov 15, 2018 11:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 6th Edition Ch4 Q7
Replies: 2
Views: 72

Re: 6th Edition Ch4 Q7

You can just do it by calculating how many bonded electron pair that S has and how many lone pairs it has and see what category of geometry structure that it falls into and you will remember the bond angle.
by Bingcui Guo
Thu Nov 15, 2018 11:51 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Structure 4.111
Replies: 2
Views: 92

Re: Molecular Structure 4.111

C in CH3 has 4 bond with no lone electron pairs so it should be tetrahedral with bond angle 109.5 degree. And the C and N forms the triple bond so the bond angle should be 180 degree. for single bond it is sp3 hybridization so C in CH3 has 3 sigma while for triple bond, it is sp hybridization and C ...
by Bingcui Guo
Thu Nov 15, 2018 11:43 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: 6th edition 4.67
Replies: 2
Views: 75

Re: 6th edition 4.67

The one with negative charge would have the lowest ionization energy because it gain one additional electron which is easy to lose. And the one with positive charge would have the highest ionization energy because it has already lost electrons to get octet structure and it is hard for it to lose one...
by Bingcui Guo
Thu Nov 08, 2018 7:47 pm
Forum: Electronegativity
Topic: Problem 2D #11 (7th edition)
Replies: 2
Views: 61

Re: Problem 2D #11 (7th edition)

The electronegativity for N is 3.0 and for O is 3.5 So N3- is more electronegative than O2-.
by Bingcui Guo
Thu Nov 08, 2018 7:38 pm
Forum: Electronegativity
Topic: Trend Exceptions
Replies: 5
Views: 133

Re: Trend Exceptions

When the element has full orbital or half full orbital structure, their structure is so stable that it is difficult for them to lose electrons, which means that it would require more energy to move one electron away from them, thus making their ionization energy higher.
by Bingcui Guo
Thu Nov 08, 2018 7:34 pm
Forum: Ionic & Covalent Bonds
Topic: HW 3.77
Replies: 4
Views: 78

Re: HW 3.77

You can decide by calculating the difference in each element's electronegativity. So the answer should be HCl, CF4, and CO2.
by Bingcui Guo
Sun Nov 04, 2018 8:34 am
Forum: Ionic & Covalent Bonds
Topic: Ionic character [ENDORSED]
Replies: 5
Views: 94

Re: Ionic character [ENDORSED]

You can see by calculating the difference of electronic affinity. C-F is larger than C-H
by Bingcui Guo
Sun Nov 04, 2018 8:32 am
Forum: Ionic & Covalent Bonds
Topic: covalent bonds
Replies: 3
Views: 82

Re: covalent bonds

It depends on whether all of its electrons pair with the electron from the other element to form a bond. If not, then the number of covalent bond is not equal to the number of valence electrons
by Bingcui Guo
Sun Nov 04, 2018 8:30 am
Forum: Ionic & Covalent Bonds
Topic: covalent bonds
Replies: 2
Views: 62

Re: covalent bonds

Because they have more than 4 electrons and due to the electrostatic force between electrons, they tend to attract more electrons to reach the 8-electron stable structure instead of losing them
by Bingcui Guo
Thu Oct 25, 2018 12:05 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Question about Ce electron configuration
Replies: 1
Views: 130

Question about Ce electron configuration

Why Ce(Cerium)'s electron configuration is [Xe}4f15d16s1? why not with 5d26s1 or 4f26s1? Cuz the energy level of 4f is lower than 5d.
by Bingcui Guo
Thu Oct 25, 2018 12:04 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Question about H electron configuration
Replies: 3
Views: 74

Question about H electron configuration

The textbook says for H and He atoms, since they have only one or two electrons which can occupy any orbitals, then how should we write the electron configuration for these 2 atoms? 1s1 1s2 or others?
by Bingcui Guo
Thu Oct 25, 2018 9:35 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Question about 4s and 3d orbitals
Replies: 1
Views: 50

Question about 4s and 3d orbitals

I know that 4s shows lower energies than 3d orbital so the electrons will fill the 4s first. But why after 2e- occupied the 4s orbitas, 4s states lower energy?
by Bingcui Guo
Sat Oct 20, 2018 9:10 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Lecture Question
Replies: 4
Views: 98

Re: Lecture Question

I think the course will only cover these 4 orbitals cuz more would be more complex.
by Bingcui Guo
Sat Oct 20, 2018 9:09 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra
Replies: 4
Views: 80

Re: Atomic Spectra

You can use the formula to calculate the different energy and thus compare. Concrete number is the answer. Hope this will help.
by Bingcui Guo
Sat Oct 20, 2018 9:07 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty
Replies: 3
Views: 63

Re: Uncertainty

It is like a reciprocal process that since the electron's path will be deflected, if you know the p, then you won't know where it will be. if you know its position, then you won't know its p
by Bingcui Guo
Mon Oct 08, 2018 2:00 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactants M9 [ENDORSED]
Replies: 2
Views: 128

Re: Limiting Reactants M9 [ENDORSED]

The copper (II) nitrate is Cu(NO3)2, the copper(II) hydroxide is Cu (OH)2. In this case, no valance value change. Just write down all the reagents and products and try to use numerical numbers to balance it. Hope this would help.
by Bingcui Guo
Mon Oct 08, 2018 1:55 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactants M19
Replies: 4
Views: 120

Re: Limiting Reactants M19

First, use the product and the mass percentage to calculate the mass of C. H. N in the caffeine. And subtract these mass from the 0.376g to calculate the mass of O in the caffeine. Second, use the mass you get from the products to calculate the moles of C.H.N.O. Third, find the simplest proportion o...
by Bingcui Guo
Mon Oct 08, 2018 1:52 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactants M11
Replies: 2
Views: 73

Re: Limiting Reactants M11

You can calculate that you have 0.4657mol P4 while have 0.18 mole O2, which means O2 is in excess. So O2 is the limiting reagent. So the P4 will be consumed up and you would get 0.04657 mole P4O6. In the second reaction, you only have 0.036 mole O2 left, which is the limiting reagent. And you could ...
by Bingcui Guo
Tue Oct 02, 2018 8:59 pm
Forum: Limiting Reactant Calculations
Topic: Percent Yield
Replies: 5
Views: 188

Re: Percent Yield

I think your theoretical yield is wrong. There are 2.0588 moles of NH3 in the reactant and they would produce 2.0588 moles of N2H4 which is about 32.94g produced. In this case, 25.5/32.95*100% is 76.5%
by Bingcui Guo
Tue Oct 02, 2018 8:54 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula
Replies: 5
Views: 106

Re: Empirical Formula

I think you can just divide all the other bigger numbers by the smallest one and round them to by the significant figure rules. Cuz I think in this case, some roundoff is acceptable
by Bingcui Guo
Mon Oct 01, 2018 9:04 pm
Forum: SI Units, Unit Conversions
Topic: Homework written in pencil or pen?
Replies: 4
Views: 130

Re: Homework written in pencil or pen?

The professor said written in whatever you want.

Go to advanced search