Search found 51 matches

by Ziyan Wang 3J
Thu Dec 05, 2019 3:37 pm
Forum: Amphoteric Compounds
Topic: 6A.17
Replies: 4
Views: 75

Re: 6A.17

When SO3 dissolves in water, it becomes H2SO4, the sulfate acid. For c and d, if they react with acidic matter, they can act as a base. If they react with basic matter, they can act as an acid.
by Ziyan Wang 3J
Thu Dec 05, 2019 3:30 pm
Forum: Lewis Acids & Bases
Topic: 6A.13
Replies: 5
Views: 40

Re: 6A.13

Yes, Ag+ + e- -> Ag, it can accept electron to be back to original state,. By definition, it is a Lewis acid.
by Ziyan Wang 3J
Thu Dec 05, 2019 2:46 pm
Forum: Bronsted Acids & Bases
Topic: Fundamental J1
Replies: 1
Views: 39

Fundamental J1

Why is not NH3 both a Bronsted acid and base? I think that it can both gain an H to form NH4+ and lose an H to be NH2-, so it should be amphoteric.
by Ziyan Wang 3J
Thu Dec 05, 2019 2:14 pm
Forum: Naming
Topic: 9C 1C
Replies: 2
Views: 23

9C 1C

Why is [Co(CN)5(OH2)]2- aquapentacyano cobaltate(Ⅲ) instead of aquapentacyano cobalt(Ⅲ)
by Ziyan Wang 3J
Thu Dec 05, 2019 2:07 pm
Forum: Naming
Topic: 9C 1A
Replies: 3
Views: 33

9C 1A

Why is [Fe(CN)6] 4- hexacyanoferrate(Ⅱ) instead of hexacyanoiron(Ⅱ)?
by Ziyan Wang 3J
Sun Dec 01, 2019 10:28 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Weak Acids & Bases
Replies: 6
Views: 57

Re: Weak Acids & Bases

Organic acids and bases are usually weak.
by Ziyan Wang 3J
Sun Dec 01, 2019 10:20 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Bronsted Acid/Base
Replies: 4
Views: 36

Re: Bronsted Acid/Base

Bronsted acid: hydrogen donor,
Bronsted base: hydrogen acceptor
by Ziyan Wang 3J
Sun Dec 01, 2019 10:13 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Why HF is a weaker acid than HCl
Replies: 17
Views: 1517

Re: Why HF is a weaker acid than HCl

Since Cl has larger radius, which means that the attraction between H and Cl is weaker, so HCl is more easily to lose the proton.
by Ziyan Wang 3J
Sun Dec 01, 2019 10:04 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Pka vs Ka
Replies: 10
Views: 108

Re: Pka vs Ka

pKa = -log[Ka], pKa usually have a range of 0 to 14
by Ziyan Wang 3J
Sun Dec 01, 2019 10:02 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Do strong acids dissociate completely in water?
Replies: 7
Views: 63

Re: Do strong acids dissociate completely in water?

Yes, you can regard strong acids to dissociate completely.
by Ziyan Wang 3J
Thu Nov 21, 2019 2:39 pm
Forum: Hybridization
Topic: 2.57
Replies: 4
Views: 73

Re: 2.57

My answer is that for first C: sp3,109.5,4 sigma, 0 pi, for second C: sp, 180, 2 sigma, 2 pi
by Ziyan Wang 3J
Thu Nov 21, 2019 2:35 pm
Forum: Hybridization
Topic: 2.57
Replies: 2
Views: 24

Re: 2.57

I did it. My answer is that for first C: sp3,109.5,4 sigma, 0 pi, for second C: sp, 180, 2 sigma, 2 pi
by Ziyan Wang 3J
Thu Nov 21, 2019 2:33 pm
Forum: Hybridization
Topic: lone pairs in hybridization
Replies: 8
Views: 47

Re: lone pairs in hybridization

In hybridization theory, lone pairs and bonding pairs are the same.
by Ziyan Wang 3J
Thu Nov 21, 2019 2:32 pm
Forum: Hybridization
Topic: Knowing when hybridization occurs
Replies: 6
Views: 56

Re: Knowing when hybridization occurs

It always occur if the atom has more than one electron domain.
by Ziyan Wang 3J
Thu Nov 21, 2019 2:30 pm
Forum: Hybridization
Topic: Hybridization with lone pairs on central atom
Replies: 6
Views: 45

Re: Hybridization with lone pairs on central atom

Yes, it's basically the same rule as the one without lone pairs. 2 electron domains -> sp, 3 -> sp2, 4 -> sp3, 5 -> sp3d, 6 -> sp3d2
by Ziyan Wang 3J
Thu Nov 14, 2019 3:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW 2.63
Replies: 2
Views: 28

Re: HW 2.63

In order to fulfill octet rule, there must be two lone pairs of electron around O (since bonding pairs only account for four electrons), thus O have 4 electron domains and its bonding angle is 109.5 (similar to tetrahedral).
by Ziyan Wang 3J
Thu Nov 14, 2019 3:09 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: format of test
Replies: 5
Views: 50

Re: format of test

I think it will be similar to test1.
by Ziyan Wang 3J
Thu Nov 14, 2019 3:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angle
Replies: 3
Views: 28

Re: Bond Angle

Linear: 180
Trigonal planar: 120
Tetrahedral: 109.5
Trigonal bipyramidal: trigonal bond angle: 120, axial bond angle: 90 and 180
Octahedral: 90 and 180
by Ziyan Wang 3J
Thu Nov 14, 2019 2:57 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: 2D. 11
Replies: 2
Views: 48

2D. 11

Arrange the anions Cl-, Br-, N 3-, and O 2- in order of increasing polarizability. What's the general rule of polarizability?
by Ziyan Wang 3J
Thu Nov 14, 2019 2:45 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.11
Replies: 4
Views: 26

2E.11

Why is the shape of IF4 - is square planar, instead of octahedral?
by Ziyan Wang 3J
Thu Nov 07, 2019 10:58 am
Forum: Electronegativity
Topic: Trend of Electronegativity
Replies: 22
Views: 136

Re: Trend of Electronegativity

Electronegativity is larger when you move close to upper right corner of the periodic table (F is the largest).
by Ziyan Wang 3J
Thu Nov 07, 2019 10:54 am
Forum: Bond Lengths & Energies
Topic: speed of electromagnetic radiation
Replies: 2
Views: 30

Re: speed of electromagnetic radiation

Speed is constant (3.00*10^8 m/s), and it equals to wavelength*frequency.
by Ziyan Wang 3J
Thu Nov 07, 2019 10:49 am
Forum: Lewis Structures
Topic: 2.7 Lewis structure for N5 +
Replies: 3
Views: 32

2.7 Lewis structure for N5 +

How to draw the Lewis structure for N5+? (N is connected in a chain)?
by Ziyan Wang 3J
Thu Nov 07, 2019 10:31 am
Forum: Octet Exceptions
Topic: General principles of octet exception
Replies: 7
Views: 50

General principles of octet exception

What is the general principles of when we should conform octet rule and when not?
by Ziyan Wang 3J
Thu Nov 07, 2019 10:16 am
Forum: Octet Exceptions
Topic: 2C.7
Replies: 2
Views: 32

2C.7

I don't quite understand how to draw the Lewis structure of ICl2 +, ICl4 -, ICl3, ICl5
by Ziyan Wang 3J
Thu Oct 31, 2019 2:04 pm
Forum: Lewis Structures
Topic: valence electrons
Replies: 4
Views: 59

Re: valence electrons

Valence electrons just refer to the electrons at the outermost shell. It increases down the group.
by Ziyan Wang 3J
Thu Oct 31, 2019 2:00 pm
Forum: Ionic & Covalent Bonds
Topic: 2A 5
Replies: 5
Views: 48

Re: 2A 5

Kristina Rizo 3K wrote:Do you have a question regarding how to figure out the ground-state electron configurations?


Yes, I don't quite understand which electrons to remove.
by Ziyan Wang 3J
Thu Oct 31, 2019 1:44 pm
Forum: Lewis Structures
Topic: Radical
Replies: 2
Views: 23

Radical

Why can we say some species with odd number valence electrons are radicals? Is the converse-negative statement also true? (Does species with even pair of electrons necessarily mean that they are not radicals?)
by Ziyan Wang 3J
Thu Oct 31, 2019 1:31 pm
Forum: Ionic & Covalent Bonds
Topic: Lewis structure
Replies: 3
Views: 34

Lewis structure

I don't quite get when we draw the Lewis structure, how do we know which atom is in the middle.
by Ziyan Wang 3J
Thu Oct 31, 2019 1:14 pm
Forum: Ionic & Covalent Bonds
Topic: 2A 5
Replies: 5
Views: 48

2A 5

Give the ground-state electron configuration expected for each of the following ions: (a) Cu+ (b) Bi 3+ (c) Ga 3+ (d) Tl 3+
by Ziyan Wang 3J
Thu Oct 31, 2019 12:56 pm
Forum: Ionic & Covalent Bonds
Topic: 2A 1
Replies: 5
Views: 52

2A 1

Give the number of valence electrons (including d electrons) for each of the following elements. (a) Sb (b) Si (c) Mn (d) B.

I wonder why the answer for (a) is 5 but that for (c) is 7.
by Ziyan Wang 3J
Tue Oct 22, 2019 11:46 am
Forum: Trends in The Periodic Table
Topic: Ionic Radii
Replies: 10
Views: 98

Re: Ionic Radii

Cations are smaller because it reduces the energy level of valence electron by 1.

Anions are bigger because the repulsion force between electrons pushes electron outward.
by Ziyan Wang 3J
Tue Oct 22, 2019 11:43 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Probability of finding an electron at a certain location
Replies: 4
Views: 40

Re: Probability of finding an electron at a certain location

I think we are not required to calculate Schrodinger's function, but only need to know s-, p-, d-, f- orbitals (it's one of the conclusions of Schrodinger's function).
by Ziyan Wang 3J
Tue Oct 22, 2019 11:32 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: example in class
Replies: 6
Views: 60

Re: example in class

It doesn't matter which orbit of x,y,z the electron actually is in because it's symmetric. You can define your x axis according to your own wish. It's just a convention to write x before y and z.
by Ziyan Wang 3J
Tue Oct 22, 2019 11:29 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Quantum Numbers
Replies: 7
Views: 98

Re: Quantum Numbers

The 4 quantum numbers describe a specific electron in a specific atom/ion. For each electron in atom/ion, it has a different quantum number.
by Ziyan Wang 3J
Tue Oct 22, 2019 11:24 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Are electrons always removed from the 4s orbital before the 3d orbital?
Replies: 6
Views: 63

Re: Are electrons always removed from the 4s orbital before the 3d orbital?

Yes, electrons with higher energy level are always removed first, and always in -f -p -d -s order
by Ziyan Wang 3J
Mon Oct 14, 2019 11:09 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Momentum
Replies: 2
Views: 61

Re: Momentum

Because for some objects (such as photon), they have no mass, but they have momentum. It will be non-sense to write it into delta x * m * delta v>= h/4pi for those objects.
by Ziyan Wang 3J
Mon Oct 14, 2019 11:03 pm
Forum: Einstein Equation
Topic: 1B.9
Replies: 5
Views: 115

Re: 1B.9

Energy per photon=h*c/lambda=6.63*10^-34*3.00*10^8/(420*10^-9)=4.74*10^-19
Total energy= 32*2=64
# of photons= Total energy/energy per photon=64/(4.74*10^-19)=1.35*10^20
by Ziyan Wang 3J
Mon Oct 14, 2019 11:01 pm
Forum: Photoelectric Effect
Topic: Homework Question 1B.9
Replies: 2
Views: 73

Re: Homework Question 1B.9

Energy per photon=h*c/lambda=6.63*10^-34*3.00*10^8/(420*10^-9)=4.74*10^-19
Total energy= 32*2=64
# of photons= Total energy/energy per photon=64/(4.74*10^-19)=1.35*10^20
by Ziyan Wang 3J
Mon Oct 14, 2019 10:53 pm
Forum: Photoelectric Effect
Topic: Confusion on equations
Replies: 9
Views: 156

Re: Confusion on equations

It just depends on what is given in the problem and what does the problem ask you to do. For example, given frequency, you can use lamda=c/v to get wavelength or E=hv to get energy.
by Ziyan Wang 3J
Mon Oct 14, 2019 10:48 pm
Forum: Properties of Electrons
Topic: Electrons wavelengths and frequency
Replies: 2
Views: 39

Re: Electrons wavelengths and frequency

Yes, electrons have its own wavelength and frequency, just as everything, its wavelength is determined by De Broglie equation. But don't mess it up with energy level. After absorbing energy of a photon, the electron jumps to a higher energy level.
by Ziyan Wang 3J
Thu Oct 10, 2019 12:00 pm
Forum: Limiting Reactant Calculations
Topic: Net Ionic Equation
Replies: 6
Views: 101

Re: Net Ionic Equation

(Cu)2+ (aq) + 2(OH)- (aq) ==> Cu(OH)2 (s). Because Na+ and NO3- are always ions, they don't participate in the reaction.
by Ziyan Wang 3J
Thu Oct 10, 2019 11:52 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg equation [ENDORSED]
Replies: 73
Views: 2009

Re: Rydberg equation [ENDORSED]

Rydberg equation states that the energy of energy levels equals to hR/n^2 (n=1,2,3...), h is planck constant(6.63*10^-34 Js), R is Rydberg constant (3.29*10^15 Hz)
by Ziyan Wang 3J
Thu Oct 10, 2019 10:43 am
Forum: Properties of Light
Topic: 1A 3 Chemical Principle 7th edition
Replies: 2
Views: 22

Re: 1A 3 Chemical Principle 7th edition

Thank you!
by Ziyan Wang 3J
Thu Oct 10, 2019 10:31 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Test 1 [ENDORSED]
Replies: 107
Views: 3252

Re: Test 1 [ENDORSED]

Does anyone know what will be tested tomorrow? Any topics on quantum world?
by Ziyan Wang 3J
Thu Oct 10, 2019 10:24 am
Forum: Properties of Light
Topic: 1A 3 Chemical Principle 7th edition
Replies: 2
Views: 22

1A 3 Chemical Principle 7th edition

Could anyone explain that why decreasing frequency of light leads to the decreasing extent of change of electromagnetic radiation?
by Ziyan Wang 3J
Thu Oct 03, 2019 4:57 pm
Forum: Balancing Chemical Reactions
Topic: H.1 Chemical Principle 7th edition
Replies: 4
Views: 64

H.1 Chemical Principle 7th edition

H.1 It appears that balancing the chemical equation Cu + SO2-> CuO + S would be simple if we could just add another O atom to the product side: Cu + SO2 -> CuO + S +O. (a) Why is that balancing procedure not allowed? (b) Balance the equation correctly.
by Ziyan Wang 3J
Thu Oct 03, 2019 4:52 pm
Forum: Empirical & Molecular Formulas
Topic: E.9 Chemical Principle 7th edition
Replies: 3
Views: 54

E.9 Chemical Principle 7th edition

Epsom salts consists of magnesium sulfate heptahydrate. Write its formula. (a) How many atoms of oxygen are in 5.15 g of Epsom salts? (b) How many formula units of the compound are present in 5.15g? (c) How many moles of water molecules are in 5.15g of Epson salts?
by Ziyan Wang 3J
Thu Oct 03, 2019 4:45 pm
Forum: Empirical & Molecular Formulas
Topic: F.3 Chemical Principle 7th edition
Replies: 2
Views: 57

F.3 Chemical Principle 7th edition

(a) Write the formula for nitric acid. (b) Without doing a calculation, estimate which element in nitric acid occurs with the greater mass percentage.
by Ziyan Wang 3J
Thu Oct 03, 2019 4:39 pm
Forum: SI Units, Unit Conversions
Topic: E.7 Chemical Principle 7th edition
Replies: 4
Views: 71

E.7 Chemical Principle 7th edition

A molecule of human DNA was found to contain 2.1 * 10^9 atoms of carbon. Calculate the chemical amount (in moles ) of carbon atoms in the molecule of DNA.
by Ziyan Wang 3J
Thu Oct 03, 2019 4:31 pm
Forum: SI Units, Unit Conversions
Topic: E.1 7th edition
Replies: 4
Views: 46

E.1 7th edition

E.1 The field of nanotechnology offers some intriguing possibilities, such as the creation of fibers one atom wide. Suppose you were able to string together 1.00 mol Ag atoms, each of radius 144pm, into one of these fibers by encapsulating them in carbon nanotubes. How long would the fiber extend?

Go to advanced search