M1V1=M2V2
(0.025)(200)=(M2)(250)
M2= (0.025)(200)/250
M2 is the concentration of the H30+
pH=-log[H3O+]
pH=-log[(0.025)(200)/250]
Search found 32 matches
- Sun Jun 10, 2018 11:29 am
- Forum: Bronsted Acids & Bases
- Topic: 12.27
- Replies: 1
- Views: 437
- Wed Jun 06, 2018 1:26 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic Bonds vs Covalent Bonds
- Replies: 7
- Views: 731
Re: Ionic Bonds vs Covalent Bonds
Ionic bonds tend to be stronger than covalent bonds due to the coulombic attraction between ions of opposite charges
- Mon Jun 04, 2018 9:33 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle [ENDORSED]
- Replies: 4
- Views: 776
Re: Bond Angle [ENDORSED]
Exact bond angles cannot be obtained from VSEPR. Exact bond angles are obtained from experimental data.
- Sun Jun 03, 2018 10:57 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: AXE formula
- Replies: 32
- Views: 12186
Re: AXE formula
The chart below will be helpful
- Sat Jun 02, 2018 6:09 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Ligands
- Replies: 8
- Views: 1329
Re: Ligands
Ligands have at least one donor atom with an electron pair used to form covalent bonds with the central atom.
- Sat Jun 02, 2018 6:05 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: formal charge and VSEPR
- Replies: 8
- Views: 1061
Re: formal charge and VSEPR
Yes, I believe the best habit to keep in mind is to draw the lewis structure with the lowest formal charge before applying VSEPR
- Fri May 25, 2018 9:00 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular geometry vs. shape [ENDORSED]
- Replies: 1
- Views: 996
Re: Molecular geometry vs. shape [ENDORSED]
Geometry refers to the arrangement of the electron groups, while shape refers to the overall shape of the molecule. Both are given by the VSEPR theory, but they are not the same thing. VSEPR electron pair arrangement and molecular shape are not the same when a central atom possesses non-bonding elec...
- Fri May 25, 2018 8:51 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: HW 4.13
- Replies: 2
- Views: 445
Re: HW 4.13
When you draw the Lewis structure of the I3- ion, you end up with two iodines attached to a central iodine. The central iodine also has three lone pairs on it. This gives you 5 regions of electron density around the central atom. This gives a trigonal bipyramidal shape. The electron pairs repel each...
- Sat May 19, 2018 8:04 pm
- Forum: Lewis Structures
- Topic: XeO2F2 Lewis Structure [ENDORSED]
- Replies: 1
- Views: 2542
Re: XeO2F2 Lewis Structure [ENDORSED]
Beginning with the n=3 principle quantum number, the d orbitals become available (l=2). Because of this, Xe can have more than an octet. While drawing the lewis structure, we are looking for the structure with a formal charge closest to zero. This is why Xe has 12 electrons instead of eight.
- Tue May 15, 2018 4:10 pm
- Forum: Lewis Structures
- Topic: Central atom
- Replies: 7
- Views: 880
Re: Central atom
Carbon would go in the middle because it has the lowest ionization energy
- Mon May 14, 2018 9:01 pm
- Forum: Coordinate Covalent Bonds
- Topic: format
- Replies: 1
- Views: 688
Re: format
I believe the line with the arrow is the standard notation
- Mon May 14, 2018 8:56 pm
- Forum: Lewis Structures
- Topic: BF3
- Replies: 2
- Views: 420
Re: BF3
The two elements that most commonly fail to complete an octet are boron and aluminum; they both readily form compounds in which they have six valence electrons, rather than the usual eight predicted by the octet rule. I believe these two are the most common ones
- Sat May 12, 2018 1:56 pm
- Forum: Trends in The Periodic Table
- Topic: electron affinity vs electronegativity?
- Replies: 2
- Views: 2607
Re: electron affinity vs electronegativity?
Electronegativity is the ability of an atom to attract electrons from outside. This is a qualitative property of an atom, and in order to compare the electronegativities of atoms in each element, a scale where relative electronegativity values reside is used. This scale is called “Pauling scale.” Ac...
- Sat May 12, 2018 1:40 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal charge of ClO2- [ENDORSED]
- Replies: 4
- Views: 3198
Re: Formal charge of ClO2- [ENDORSED]
I found a video that goes through the step by step process of identifying the formal charge and drawing the lewis structure for ClO2-
https://www.youtube.com/watch?v=GTKW7nDzVCA
https://www.youtube.com/watch?v=GTKW7nDzVCA
- Thu May 10, 2018 1:27 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: energy emitted
- Replies: 2
- Views: 568
Re: energy emitted
The first equation is used to calculate the frequency of the emitted light when electrons transition between energy levels. When light is absorbed, the transition is up to a higher energy level. When light is emitted, the transition is down to a lower energy level. The calculation is always done usi...
- Thu May 10, 2018 1:17 pm
- Forum: Resonance Structures
- Topic: Resonance Structures and Formal charges
- Replies: 7
- Views: 966
Re: Resonance Structures and Formal charges
Lewis structures incorporate an atom's formal charge, which is the charge on an atom in a molecule, assuming that electrons in a chemical bond are shared equally between atoms. When multiple Lewis structures can represent the same compound, the different Lewis formulas are called resonance structures.
- Sun May 06, 2018 11:56 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: F orbital
- Replies: 6
- Views: 986
Re: F orbital
A good conceptual concept to remember is that a shell is bigger than a sub shell which is bigger than an orbital
Shell > Subshell > orbital
Shell > Subshell > orbital
- Wed May 02, 2018 9:42 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 2.19 part d
- Replies: 2
- Views: 381
Re: 2.19 part d
The value of n determines the possible values for l. For any given shell, the number of subshells can be found by l = 0,.....,n-1. In the case of n=4, l=0,1,2,3. This tells us that there are 4 possible sub-shells (0,1,2,3). When l is 0, then the orbital is s. When l is 1, then the orbital is p. When...
- Wed May 02, 2018 9:31 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Question 2.13
- Replies: 2
- Views: 353
Re: Question 2.13
In Outline 2, it states that we must be able to "describe and identify s-, p-, and d-orbitals.". What you mentioned does suffice in terms of what we should know about the orientation along the different axes. One thing to keep in mind is that the p orbital has nodal planes, unlike the s or...
- Sun Apr 29, 2018 8:45 pm
- Forum: DeBroglie Equation
- Topic: Quanta
- Replies: 5
- Views: 725
Re: Quanta
Electrons exist on specific energy levels and cannot exist in between them. When an electron moves to another energy level, it must release or absorb very specific amounts of energy. This is what quantized means: the amount of energy absorbed or released can only be specific quantities called quanta
- Tue Apr 24, 2018 5:44 pm
- Forum: DeBroglie Equation
- Topic: equations that apply to light only/everything else but light
- Replies: 8
- Views: 970
Re: equations that apply to light only/everything else but light
It does not apply to photons
- Sun Apr 22, 2018 9:49 pm
- Forum: DeBroglie Equation
- Topic: 1.39 and 1.23
- Replies: 3
- Views: 487
Re: 1.39 and 1.23
It will be on the cover sheet. Conversion from eV to J, certain constants, and masses of particles will be there.
- Sat Apr 21, 2018 11:46 pm
- Forum: DeBroglie Equation
- Topic: equations that apply to light only/everything else but light
- Replies: 8
- Views: 970
Re: equations that apply to light only/everything else but light
The photon is a massless particle. According to theory it has energy and momentum but no mass, and this is confirmed by experiments. Light carries momentum and will exert pressure on a surface. This is not evidence that it has mass since momentum can exist without mass. Sometimes people like to say ...
- Thu Apr 19, 2018 2:05 pm
- Forum: DeBroglie Equation
- Topic: HW 1.37 [ENDORSED]
- Replies: 6
- Views: 862
Re: HW 1.37 [ENDORSED]
After finding the values of both the wavelengths for the proton and the neutron, subtract the wavelength of the neutron from the wavelength of the proton. After you find the difference, multiply the difference by 100 and divide it by the wavelength of the neutron to find out what percentage of the n...
- Wed Apr 18, 2018 8:37 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: The Negative Sign in En = -hR/n^2
- Replies: 5
- Views: 620
Re: The Negative Sign in En = -hR/n^2
The negative sign implies that the bound electron has lower energy than the free electron. The eletron's energy has decreased, and the energy is released as electromagnetic radiation
- Wed Apr 18, 2018 8:23 pm
- Forum: DeBroglie Equation
- Topic: 10^-18
- Replies: 3
- Views: 455
Re: 10^-18
The electromagnetic spectrum (EMS) is the general name given to the known range of electromagnetic radiation. Wavelengths increase from approximately 10^-18 m to 100 km, and this corresponds to frequencies decreasing from 3 × 10^26 Hz to 3 ×10^3 Hz. The smallest electromagnetic waves we know about a...
- Sat Apr 14, 2018 6:21 pm
- Forum: SI Units, Unit Conversions
- Topic: Length Units
- Replies: 15
- Views: 1510
Re: Length Units
Stick to the SI units, unless a question asks for a specific type of unit.
- Sat Apr 14, 2018 12:53 pm
- Forum: SI Units, Unit Conversions
- Topic: SI Units- Bond Length [ENDORSED]
- Replies: 1
- Views: 1036
Re: SI Units- Bond Length [ENDORSED]
Bond lengths have traditionally been expressed in Ångstrom units (1Å = 10^-10 m), but picometers are now preferred (1 pm= 10^-12m ). We use these units because the bond length is a very small length. Also, it is more efficient to use 1pm than to constantly write out 10^-12m.
- Sun Apr 08, 2018 12:30 pm
- Forum: SI Units, Unit Conversions
- Topic: writing out conversions in one long line vs. steps
- Replies: 16
- Views: 1461
Re: writing out conversions in one long line vs. steps
There is no right or wrong way, as long as you get to the same answer with the right units. It is totally up to preference. However, writing out the conversions in one lone line will make it easier to visualize the dimensional analysis as you cross out all your units to eventually arrive at your des...
- Sun Apr 08, 2018 12:08 pm
- Forum: General Science Questions
- Topic: Rusty on High School Chem [ENDORSED]
- Replies: 347
- Views: 431933
Re: Rusty on High School Chem [ENDORSED]
Best Resources:
1. All the resources Dr. Lavelle provides on a weekly basis
2. Khan Academy
3. Crash Course
4. Bozeman Science
5. Your friend who's a chem wiz
1. All the resources Dr. Lavelle provides on a weekly basis
2. Khan Academy
3. Crash Course
4. Bozeman Science
5. Your friend who's a chem wiz
- Sun Apr 08, 2018 12:00 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Dimensional Analysis Help [ENDORSED]
- Replies: 6
- Views: 690
Re: Dimensional Analysis Help [ENDORSED]
Dimensional Analysis is a great way to keep track of all your units to make sure that everything crosses out at the end, leaving you with your desired units. The easiest way to perform it is by basically multiplying all your quantities at the same time in one line to see which units cross out. This ...
- Sun Apr 08, 2018 11:42 am
- Forum: SI Units, Unit Conversions
- Topic: why do I not use avogadro's number
- Replies: 5
- Views: 1942
Re: why do I not use avogadro's number
You can use avogadro's number to solve the problem; however, it would take longer and woudn't be as productive. In this case, it's much easier to just divide the mass of the sample by the mass of the individual atom to get the number of atoms since we already have both values: mass(sample) / mass(at...