Search found 21 matches

by Isabella Zizolfi 2F
Mon Dec 04, 2017 10:19 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: What is 1/K? [ENDORSED]
Replies: 4
Views: 474

Re: What is 1/K? [ENDORSED]

1/K is the reciprocal of K for that reaction
if you know the value of K of the forward reaction (for example 5) and the exercise asks you to find the K of the reverse reaction, you can find it by calculating the reciprocal of K of the forward reaction (in our example 1/5 which is 0.2)
by Isabella Zizolfi 2F
Mon Dec 04, 2017 10:11 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted Acid and Base vs Lewis Acid and Base
Replies: 3
Views: 173

Re: Bronsted Acid and Base vs Lewis Acid and Base

Bronsted: H+
- Bronsted acids are proton donor
- Bronsted bases are proton acceptor

Lewis: e-
- Lewis acids are e- acceptor and they accept a lone pair
- Lewis bases are e- donor and the donate a lone pair
by Isabella Zizolfi 2F
Mon Dec 04, 2017 10:08 pm
Forum: Amphoteric Compounds
Topic: 12.17 part b
Replies: 3
Views: 296

Re: 12.17 part b

1) It is a nonmetal so this means that it forms acidic oxides
2) it takes e- so it is an electron acceptor
by Isabella Zizolfi 2F
Mon Dec 04, 2017 10:05 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Strong Acids and Weak Bases
Replies: 1
Views: 185

Strong Acids and Weak Bases

I have some problems recognizing when a acid is stronger than another acid and when a base is weaker than anther base. Can someone explain me how to do it?
by Isabella Zizolfi 2F
Sat Dec 02, 2017 3:58 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strong acid vs weak acid [ENDORSED]
Replies: 7
Views: 268

Re: Strong acid vs weak acid [ENDORSED]

• STRONG ACID PRODUCES MORE PROTOS IN SOLUTION THAN A WEAK ACID • STRON ACIDS ALMOST COMPLETELY IONIZED IN SOLUTION. HCl, HBr, etc. • CALCULATIONS INVOLVING STRON ACIDS (OR BASE): APPROXIMATE BY ASSUMING 100% IONIZED (DISSOCIATED) THEREFORE 0.1M HCl (Aq) IMPLIES 0.1M H3O+(Aq) AND 0.1M Cl- (Aq) WHAT ...
by Isabella Zizolfi 2F
Mon Nov 27, 2017 10:54 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ex 17.37 [ENDORSED]
Replies: 1
Views: 115

Ex 17.37 [ENDORSED]

Exercise number 17.34 for point c and d. Can you tell me why the coordination number of [PtCl2(en)2]^2+ is 6 and the coordination number of [Cr(edta)]^-1 is also 6?
by Isabella Zizolfi 2F
Mon Nov 27, 2017 10:49 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: polydentate and monodentate
Replies: 1
Views: 123

polydentate and monodentate

How do you determine that an atom is mono dentate? do you have to look at the lone pairs or at the bonds?
by Isabella Zizolfi 2F
Thu Nov 16, 2017 5:50 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 789146

Re: Post All Chemistry Jokes Here

What do you do with a sick chemist?
if you can't helium and you can't curium, then you might as well barium
by Isabella Zizolfi 2F
Thu Nov 16, 2017 5:48 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7337
Views: 789146

Re: Post All Chemistry Jokes Here

What is the chemical formula for banana?
BaNa2
by Isabella Zizolfi 2F
Wed Nov 08, 2017 11:26 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant
Replies: 3
Views: 205

Re: Limiting Reactant

Firstly I usually find the moles for each of the reactant and then through a ratio (moles of first reactant : x = stoichiometric number first reactant : stoichiometric number second reactant) I calculate the amount of moles of the second reactant I should need and then I compare the moles that I hav...
by Isabella Zizolfi 2F
Wed Nov 08, 2017 11:18 pm
Forum: Electronegativity
Topic: Electronegativity and Bond Strength
Replies: 4
Views: 229

Re: Electronegativity and Bond Strength

Bond strength and electronegativity are not really strictly related, but bond strength is more connected with the length of the atomic radius: smaller the atomic radius is, stronger the bond will be. In fact between CF4, CCl4, and CBr4, CF4 has the strongest bond because in all the three molecules w...
by Isabella Zizolfi 2F
Wed Nov 01, 2017 11:37 pm
Forum: *Shrodinger Equation
Topic: What do I need to know
Replies: 1
Views: 227

Re: What do I need to know

you just have to know that it describes the path/wavelength/orbital of an e- and it is a cos or sen function. You do not need to know the actual equation.
by Isabella Zizolfi 2F
Wed Nov 01, 2017 11:25 pm
Forum: Trends in The Periodic Table
Topic: Trends in the periodic table
Replies: 3
Views: 165

Re: Trends in the periodic table

Electron Affinity is the energy associated with the addition of an electon to a gaseous atom. It increases from left to right (period) and decreases from the top to the bottom (group)
by Isabella Zizolfi 2F
Thu Oct 26, 2017 11:02 am
Forum: Trends in The Periodic Table
Topic: d5 and d10 e- exception
Replies: 4
Views: 358

Re: d5 and d10 e- exception

Yes, all the elements in group 11 and 6 are considered exceptions and so they act like Cr and Cu
by Isabella Zizolfi 2F
Thu Oct 26, 2017 10:58 am
Forum: Quantum Numbers and The H-Atom
Topic: Homework Question 2.17 part d
Replies: 5
Views: 251

Re: Homework Question 2.17 part d

l=0 --> s --> 1 orbital, 2 electrons
l=1--> p --> 3 orbitals, 6 electron
l=2 --> d --> 5 orbitals, 10 electrons
l=3 --> f --> 7 orbitals, 14 electrons
by Isabella Zizolfi 2F
Thu Oct 19, 2017 12:04 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Module Question 44
Replies: 2
Views: 170

Re: Atomic Spectra Module Question 44

the answer is B because
a) you have to use the following formula in order to get the frequency --> frequency= R (1/n^2 - 1/n^2) [in this case n=4 and n=1 so frequency= R (1/16 - 1)
b) once you get the frequency you just have to use the formula wavelength= c(speed of light)/frequency
by Isabella Zizolfi 2F
Wed Oct 18, 2017 11:47 pm
Forum: Properties of Light
Topic: Wavelength and Frequency
Replies: 3
Views: 191

Re: Wavelength and Frequency

we know that c= frequency x wavelength. c is a constant (speed of light), so from the first formula we can get that frequency=c/wavelength, from this you can see that frequency and wavelength are inversely proportional. In fact as the value of the wavelenght increases the value of the frequency decr...
by Isabella Zizolfi 2F
Tue Oct 10, 2017 11:22 am
Forum: Properties of Light
Topic: Photoelectric Effect Post-Module Assessment (33A, 34B)
Replies: 1
Views: 122

Photoelectric Effect Post-Module Assessment (33A, 34B)

33. Molybdenum metal must absorb radiation with a minimum frequency of 1.09 x 1015 s-1 before it can emit an electron from its surface. What is the minimum energy needed to produce this effect? If molybdenum is irradiated with 194 nm light, what is the maximum possible kinetic energy of the emitted ...
by Isabella Zizolfi 2F
Tue Oct 10, 2017 11:19 am
Forum: Properties of Light
Topic: Photoelectric Effect Post-Module Assessment (28B) [ENDORSED]
Replies: 1
Views: 140

Photoelectric Effect Post-Module Assessment (28B) [ENDORSED]

28. Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. How much energy is required to remove an electron from one sodium atom? What is the frequency of the incident light on the sodium metal surface? Could y...
by Isabella Zizolfi 2F
Thu Oct 05, 2017 4:48 pm
Forum: Empirical & Molecular Formulas
Topic: F. 9
Replies: 2
Views: 370

Re: F. 9

Firs you have to find the empirical formula (which is C8H8O3) then you have to calculate the atom ratio (which is, in this case, 8:8:3)
by Isabella Zizolfi 2F
Thu Oct 05, 2017 4:42 pm
Forum: Empirical & Molecular Formulas
Topic: Identifying Empirical and Molecular Formulas [ENDORSED]
Replies: 13
Views: 1105

Re: Identifying Empirical and Molecular Formulas [ENDORSED]

The empirical formula shows the relative numbers of atoms of each element present in the compound (It is the simplest positive integer ratio of atoms present in a compound)
The molecular formula shows the actual numbers of atoms of each element in a molecule

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