Search found 31 matches

by Chris Qiu 1H
Mon Jun 11, 2018 2:05 am
Forum: Determining Molecular Shape (VSEPR)
Topic: 4.75 [ENDORSED]
Replies: 1
Views: 87

Re: 4.75 [ENDORSED]

Hi Haya! The percent composition you can turn into grams turning the percents into decimals and multiplying by 100. Afterwards you would turn all the grams into moles of their respective element. Then you take the smallest mole value and divide it by all of the values. For this problem that would ge...
by Chris Qiu 1H
Mon Jun 11, 2018 1:55 am
Forum: Calculating the pH of Salt Solutions
Topic: salts & conjugate base
Replies: 1
Views: 176

Re: salts & conjugate base

Salts usually dissociate into its two parts in water. Conjugate bases accept Protons and would thus take it from the water making OH ions. OH ions are associated with bases and would thus raise the pH.
by Chris Qiu 1H
Mon Jun 11, 2018 1:47 am
Forum: Determining Molecular Shape (VSEPR)
Topic: T-Shape
Replies: 6
Views: 237

Re: T-Shape

There are three angles you look at when you view t shaped. Without taking into account lone pair repulsion you would have two 90 degree angles and one 180 degree. However the lone pairs will push the two atoms making the top of the T closed towards the third atom. This would mean that the 90 degree ...
by Chris Qiu 1H
Sat Jun 09, 2018 7:11 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand bind to metal
Replies: 2
Views: 91

Re: Ligand bind to metal

Pi bonds cant rotate so there will be no double bound ligands.
by Chris Qiu 1H
Sat Jun 09, 2018 7:10 pm
Forum: Octet Exceptions
Topic: expanded octet
Replies: 12
Views: 542

Re: expanded octet

Anything past the third group can have an expanded octet.
by Chris Qiu 1H
Sat Jun 09, 2018 7:09 pm
Forum: Conjugate Acids & Bases
Topic: Difference between Lewis and conjugate acids and bases
Replies: 4
Views: 373

Re: Difference between Lewis and conjugate acids and bases

Lewis acids accept electrons while lewis bases donate electrons. What the acid becomes is the conjugate base in the reaction and what the base becomes is the conjugate acid.
by Chris Qiu 1H
Mon May 28, 2018 9:52 pm
Forum: Bond Lengths & Energies
Topic: Highest Ionization Energy
Replies: 2
Views: 188

Re: Highest Ionization Energy

Is this question asking about what atom will be the central atom? In that case for BrB there technically isn't a central atom. For PS2 its typical for this case for the element that has only one of it (P in this case) to be the central atom.
by Chris Qiu 1H
Mon May 28, 2018 9:50 pm
Forum: Ionic & Covalent Bonds
Topic: Double/Triple Bonds
Replies: 8
Views: 300

Re: Double/Triple Bonds

All atoms that have enough electrons to form triple and double bonds can form them. However, whether they form them or not is dependent on the formal charge of the molecule. (You try to minimize the amount of formal charges that arn't zero)
by Chris Qiu 1H
Mon May 28, 2018 9:47 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW 4.3 - structure of CH2F2
Replies: 2
Views: 202

Re: HW 4.3 - structure of CH2F2

If I recall, the professor told us we would not have to draw vsepr structures (what your talking about), but we would have to know he names of the shapes and the bond angles.
by Chris Qiu 1H
Fri May 18, 2018 8:11 pm
Forum: Bond Lengths & Energies
Topic: Bond Strength In Same Group
Replies: 6
Views: 708

Re: Bond Strength In Same Group

You go off of polarzability, if the elements that are bound in one instance have higher polarizability then they will create a stronger bond.
by Chris Qiu 1H
Fri May 18, 2018 8:09 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Does being more polarizable= Being stronger?
Replies: 2
Views: 258

Re: Does being more polarizable= Being stronger?

High polarizability creates stronger bonds which is why ions with bigger atomic radii (higher polarizability) like Br2 and I2 are not gases
by Chris Qiu 1H
Fri May 18, 2018 8:03 pm
Forum: Dipole Moments
Topic: polarization power
Replies: 3
Views: 152

Re: polarization power

This related to cations, Polarizability relates to anions
by Chris Qiu 1H
Sun May 13, 2018 3:33 pm
Forum: Lewis Structures
Topic: Radicals [ENDORSED]
Replies: 3
Views: 126

Re: Radicals [ENDORSED]

Count how many valence electrons each atom has, add them together taking into account the charge, if that number is odd then it will be a radical.
by Chris Qiu 1H
Sun May 13, 2018 3:26 pm
Forum: Lewis Structures
Topic: Valence Electrons by Group
Replies: 2
Views: 76

Re: Valence Electrons by Group

Valence electrons for Cobalt are tricky since it is a transition metal. Writing the shorthand electron configuration for Cobalt ([Ar] 3d7 4s2) there are nine electrons which you actually specified. Thus Cobalt has 9 valence electrons, however the D orbital isn't known to get involved in bonds and li...
by Chris Qiu 1H
Sun May 13, 2018 3:16 pm
Forum: Octet Exceptions
Topic: expanded octet XeF4
Replies: 8
Views: 353

Re: expanded octet XeF4

The expanded octet rule can only apply to elements on the third row of the periodic table or higher due to the presence of the D-orbitals. Florine does not fit those criteria so there is only one option for the extra electrons, placing them on Xenon.
by Chris Qiu 1H
Sun May 06, 2018 11:09 pm
Forum: Properties of Light
Topic: Test 2 Question 4
Replies: 8
Views: 282

Re: Test 2 Question 4

you would have to use the reinberg equation with a Balmer series drop (you would know you need to see this since the wavelength is in the visible range which is the balmer series) a balmer series is a drop from n=x to n=2
by Chris Qiu 1H
Sun May 06, 2018 11:06 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: How many significant figures? [ENDORSED]
Replies: 5
Views: 164

Re: How many significant figures? [ENDORSED]

I'd keep 3-4 sig figs just to be safe. Having only one sig fig for a value that wont be a whole number (or a single digit for that manner) doesn't make too much sense.
by Chris Qiu 1H
Sun May 06, 2018 11:04 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Energy difference between 4s and 3d
Replies: 3
Views: 177

Re: Energy difference between 4s and 3d

What you wrote says 3p but you asked about 3d in the header so I assume you just miss-typed. We know that the 4s electrons are lost first during ionization which means that they are of a higher energy level than the 3d orbital since the highest electrons are found farthest away from the nucleus, thu...
by Chris Qiu 1H
Sun Apr 29, 2018 9:48 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Using shorthand [Ar] [ENDORSED]
Replies: 5
Views: 121

Re: Using shorthand [Ar] [ENDORSED]

Since it isn't very informative when you just but [Ar] for shorthand it would be safer to just use the noble gas before it and write full orbitals.
by Chris Qiu 1H
Sun Apr 29, 2018 9:46 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: The concept of Orbitals
Replies: 12
Views: 306

Re: The concept of Orbitals

An orbital is a description of the behavior of an electron as it surrounds the atom. The different types of orbitals (s,p,d,f) exhibit different movements each orbital typically has more energy than the one before it (except for the d orbitals in our respect)
by Chris Qiu 1H
Sun Apr 29, 2018 9:43 pm
Forum: Quantum Numbers and The H-Atom
Topic: Four Different Quantum Numbers
Replies: 7
Views: 237

Re: Four Different Quantum Numbers

This basically means that no electron can have the same spin as any other electron and there are set number of electrons that can be in one orbital.
by Chris Qiu 1H
Sun Apr 22, 2018 3:42 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg [ENDORSED]
Replies: 5
Views: 246

Re: Rydberg [ENDORSED]

You would use this equation when trying to find the wavelength of a electron that has gone from a high energy level (n2) to a lower energy level (n1). Hope this helps :)
by Chris Qiu 1H
Sun Apr 22, 2018 3:39 pm
Forum: Einstein Equation
Topic: Looking over discussion problems
Replies: 2
Views: 111

Re: Looking over discussion problems

When you increase the brightness of a light (that has a frequency that you know can eject the electrons) you are increasing the intensity so there are more photons being emited, thus more electrons will be sent out. For the frequency, there is a underlying frequency a metal requires in order to ejec...
by Chris Qiu 1H
Sun Apr 22, 2018 3:23 pm
Forum: Properties of Light
Topic: Question About Photons [ENDORSED]
Replies: 3
Views: 142

Re: Question About Photons [ENDORSED]

Through the equation E^2= [(mc)^2]^2+(pc)^2 when m is equal to zero (since we are taking the momentum of a photon) you are can deduce the function E=pc, which you then can turn into p=E/c. We know the energy of a photon is given by E=(hc)/(wavelength) so when putting that into the equation you get p...
by Chris Qiu 1H
Sun Apr 15, 2018 12:31 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Question 1.13
Replies: 1
Views: 67

Re: Question 1.13

For the equation the n1 is meant to represent the lower energy level n of the transition. This is to avoid coming out with a negative value when plugging into the equation.
by Chris Qiu 1H
Sun Apr 15, 2018 12:24 pm
Forum: Properties of Light
Topic: 1.11
Replies: 2
Views: 107

Re: 1.11

Waves in a series all have similar wavelengths and all transition their electron to the same energy level. i.e the Lyman series are all ultraviolet waves that drop to n1, paschen's are all infrared and fall to n3
by Chris Qiu 1H
Sun Apr 15, 2018 12:10 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Solving 1.11 [ENDORSED]
Replies: 3
Views: 142

Re: Solving 1.11 [ENDORSED]

Grouping these waves into series is helpful because it allows the waves to be categorized by energy levels. i.e Lyman's series are all ultraviolet, Paschen's lie in infrared.
by Chris Qiu 1H
Sun Apr 15, 2018 12:01 pm
Forum: Limiting Reactant Calculations
Topic: What To Do When Mole Ratios Are Present? [ENDORSED]
Replies: 2
Views: 156

Re: What To Do When Mole Ratios Are Present? [ENDORSED]

For balanced equations where the moles arn't one to one make a conversion like how you would do with grams or liters. Manipulate the ratio, whatever it may be, so that the moles of whichever element you want it the only unit remaining. i.e If you have 1.6 moles of compound X and want to know how muc...
by Chris Qiu 1H
Fri Apr 06, 2018 1:23 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Dimensional Analysis Help [ENDORSED]
Replies: 6
Views: 315

Re: Dimensional Analysis Help [ENDORSED]

You use dimensional analysis whenever you need to change a value from one type of unit (meters) to another unit (kilometers). I find the easiest way to do these calculations is to make sure that after the calculation the only unit(s) that haven't canceled out are your desired units.
by Chris Qiu 1H
Fri Apr 06, 2018 1:19 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Which mass of oxygen should be used? [ENDORSED]
Replies: 23
Views: 958

Re: Which mass of oxygen should be used? [ENDORSED]

Typically you use 16 as the mass for oxygen. For this case the difference between 15.999 and 16 is so small it never really matters once you take significant figures into consideration.

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