Search found 65 matches

Thu Jan 14, 2021 1:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Why is the concentration of Ba2+ the same as barium hydroxide?
Replies: 7
Views: 32

Re: Why is the concentration of Ba2+ the same as barium hydroxide?

you always want to look at the ratios of the equation for problems like these. This is why it is so important to balance an equation prior to working out the math. Here, there is a 1:1 ration, explaining why Ba2+ has the same conc
Thu Jan 14, 2021 1:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pH and pOH vs. pKa and pKb
Replies: 9
Views: 44

Re: pH and pOH vs. pKa and pKb

I believe your statement is correct. I like to think of pK values as a dissociation value that tells me how strong or weak an acid or base is.
Thu Jan 14, 2021 1:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Lecture Question
Replies: 9
Views: 61

Re: Lecture Question

CH3COOH is ab acid I think he just made a mistake
Thu Jan 14, 2021 1:35 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pH and pKa
Replies: 6
Views: 26

Re: pH and pKa

PH= tells us how acidic something is (can indirectly tell you how basic it is also)
Pka= dissociation of acid or base
Thu Jan 14, 2021 1:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: net ionic equations
Replies: 4
Views: 24

Re: net ionic equations

there are equations where you can cancel out spectator ions similar to a math equation. I dont believe we have to know this in depth though. Correct me if I am wrong please
Thu Jan 07, 2021 10:04 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equil. Part 3 Module
Replies: 2
Views: 25

Re: Chemical Equil. Part 3 Module

you can disregard the c since the initial was 0M. proceed with products over reactants. You numerator should be 4x^2
Thu Jan 07, 2021 10:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling 6
Replies: 2
Views: 20

Re: Sapling 6

I cant copy and paste due to formatting issues??? but by kc was 0.061. N2 is 1.43M, H2 is 6.94M, an NH3 Is 2.45M. They are asking was is Q
Thu Jan 07, 2021 9:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling 6
Replies: 2
Views: 20

Sapling 6

For question 6 on sapling, I keep getting the value 0.01. Im not sure what I am doing wrong since I am by putting products over reactants. Is there a step I am missing?
Thu Jan 07, 2021 9:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: dobule arrows
Replies: 6
Views: 50

Re: dobule arrows

double arrow is the emphasize the quantity of the number. MUCH less than or MUCH more than
Thu Jan 07, 2021 9:43 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #5
Replies: 3
Views: 32

Re: Sapling #5

you have to manipulate the equations to make it look like the given one. when I did my work, I had to multiple the first equation by three and cube the square root and reverse the third equation and inverse the Ka.once you line those equations up, you can cancel the intermediate terms and multiply y...
Tue Dec 08, 2020 6:38 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: 6B.5
Replies: 4
Views: 171

Re: 6B.5

You can start to approach this by simply knowing that the addition of pOH and pH Is equal to 14 so (pOH+pH=14). So if you find the pH of the molecule using the molarity you found in each problem you can just subtract it to 14 and get pOH or vice versa. How do you solve for (c)? multiply the molarit...
Tue Dec 08, 2020 6:36 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Are noble gases considered bases?
Replies: 9
Views: 1169

Re: Are noble gases considered bases?

noble gases are highly stable and it does not want to deviate from its natural state. acid and bases give or take electrons which is the opposite of what noble gases want to do so it will be neither.
Tue Dec 08, 2020 6:33 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Which is the stronger acid?
Replies: 9
Views: 185

Re: Which is the stronger acid?

you can also think of the electronegativity in the two O 'diluting' the charge, making it easier to break the bond the molecule
Tue Dec 08, 2020 6:32 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Which is the stronger acid?
Replies: 9
Views: 185

Re: Which is the stronger acid?

if you draw the lewis structure, you can see that the two O that have a large E.N. will cause electron withdraw. Because of the stronger distribution of charges, it is stronger
Tue Dec 08, 2020 6:29 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Oxides
Replies: 3
Views: 46

Re: Oxides

because of their small size and high charge, it makes it easier to dissociate. Because of how easily the bonds break, it is a strong acid.
Fri Dec 04, 2020 7:08 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Compound
Replies: 6
Views: 49

Re: Coordination Compound

Fri Dec 04, 2020 7:06 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: octahedral
Replies: 4
Views: 50

Re: octahedral

its considered octahedral because a molecule with six bonds will create a geometric shape that has 8 faces.
Fri Dec 04, 2020 7:05 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Aqueous
Replies: 4
Views: 44

Re: Aqueous

the solvent must be water. that it is what it means to be aqueous
Fri Dec 04, 2020 7:04 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: chelate
Replies: 7
Views: 55

Re: chelate

it is because of the sigma bond. Single bonds are flexible and can move while pi bonds are rigid. This is why double bonded molecules have less freedom to move as compared to single bonds
Fri Dec 04, 2020 7:03 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: chelate
Replies: 7
Views: 55

Re: chelate

it is because of the sigma bond. Single bonds are flexible and can move while pi bonds are rigid. This is why double bonded molecules have less freedom to move as compared to single bonds
Fri Dec 04, 2020 7:01 pm
Forum: Naming
Topic: Polydentate
Replies: 8
Views: 58

Polydentate

When do we know if something is a polydentate? Is it the length of the molecule that indicates it is or do we have to draw the lewis structure.
Sun Nov 29, 2020 11:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Equatorial/ Axial Planes
Replies: 14
Views: 73

Re: Equatorial/ Axial Planes

axial is up and down (north or south) so similar to the poles on the earth. Equatorial is horizontal plane similar to the equator on the earth.
Fri Nov 27, 2020 8:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Shape Names
Replies: 50
Views: 284

Re: Shape Names

you can call it bent or angular they're the same
Fri Nov 27, 2020 8:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: lone pairs on H2O
Replies: 4
Views: 51

Re: lone pairs on H2O

I would suggest looking at the geometry instead of the lewis structure. the lewis structures are not a good indicator oh the location of the lone pairs. Although Xef2 and h2o have a diff number of lone pairs, they are both linear because the lone pairs want to repel each other
Fri Nov 27, 2020 7:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Geometry
Replies: 7
Views: 47

Re: Molecular Geometry

This isnt really for memorizing but I looked up molecular geometry table that corresponds number of lone pairs with number of electron density regions.
Fri Nov 27, 2020 7:45 pm
Forum: Naming
Topic: -ate
Replies: 11
Views: 295

Re: -ate

ate is specific for an anion
Fri Nov 27, 2020 7:42 pm
Forum: Naming
Topic: Naming Complexes
Replies: 7
Views: 64

Re: Naming Complexes

I agree with Syndey. We havent gone over it in depth yet so maybe hold off on the problems until the next lectures. He briefly when over it with the last example of Wednesdays lecture
Thu Nov 19, 2020 6:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles (<109 or 104.5, etc)
Replies: 8
Views: 56

Re: Bond Angles (<109 or 104.5, etc)

if there is an e- repulsion that causes an angle to be less than 109, you can just write your answer as <109 because Lavelle said we don't need to know the exact angle (104.5) and because we don't know how to calculate it in this class.
Thu Nov 19, 2020 6:18 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pair E-
Replies: 47
Views: 257

Re: Lone Pair E-

it counts as its own electron density because it region contains electrons. You only look at the elements when determine the basic shape
Thu Nov 19, 2020 6:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: sapling q 5
Replies: 4
Views: 48

Re: sapling q 5

From my understanding, axial atoms are located at the poles, at the top and bottom of a structure. Equatorial atoms would be located on the plane horizontal to the central atom. For example, in the structure of SF4, the lone pair would be on the equatorial plane to minimize the number of 90 degree ...
Thu Nov 19, 2020 6:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 16
Views: 248

Re: bond angles

Can someone explain how we knows what the bond angles are? I'm still confused about how we know that, or like how we know that an angle is less than some other angle(for example when they say that an angle is <120, how do they reach that conclusion)? an angle may be smaller than 120 because there i...
Thu Nov 19, 2020 6:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: lone pairs
Replies: 6
Views: 64

Re: lone pairs

I know that lone pairs take up greater volume but could someone explain again why they take up greater volume? bonded e- only take up the space between the two elements because of its attraction to the nucleus. An unbonded pair of e- are not bound to two nuclei and therefore, have more room to move...
Sun Nov 15, 2020 10:21 pm
Forum: Bond Lengths & Energies
Topic: calculating bond lengths
Replies: 7
Views: 55

Re: calculating bond lengths

I think the textbook questions regarding bond length are going to be similar to the midterm ones. In the textbook, they give you bond lengths for each element and you just add them together. So yes we should know how to calculate it but its just simple addition.
Thu Nov 12, 2020 8:03 pm
Forum: Lewis Structures
Topic: Lewis structures of Polyatomic Ions
Replies: 2
Views: 39

Re: Lewis structures of Polyatomic Ions

TrishaP_3E wrote:Hi!
Knowing how to draw Lewis structures for ionic compounds is on Outline Three, so I'd assume we'd need to know it.

oh I wasn't aware of this thank you!
Thu Nov 12, 2020 6:08 pm
Forum: Student Social/Study Group
Topic: Participation
Replies: 45
Views: 338

Re: Participation

click on your name and it should tell you how many posts you have. Just remember each week requires 5 posts so remember to account for that when calculating if you get all your participation points. If we didn't do a full 5 one week, but then made up for it the next week does that count? Like only ...
Thu Nov 12, 2020 6:05 pm
Forum: Lewis Structures
Topic: Lewis structures with Noble gases
Replies: 5
Views: 37

Re: Lewis structures with Noble gases

Elements in the 3rd row and beyond can have an expanded octet due to d-orbitals. Xe is in row 5 so it has d-orbitals that can accommodate additional electrons. This does not apply to EVERY noble gas. This only applies to noble gasses in the 3rd row, 4th row, etc. How do we know which elements can h...
Thu Nov 12, 2020 6:03 pm
Forum: Lewis Structures
Topic: Lewis structures of Polyatomic Ions
Replies: 2
Views: 39

Lewis structures of Polyatomic Ions

Should we know how to draw lewis structures of ionic compounds such as question 2b.9? There is no covalent bonding in the questions so I was wondering if anyone knew if we should be comfortable drawing ionic lewis structures.
Thu Nov 12, 2020 10:05 am
Forum: Lewis Structures
Topic: Lewis structures with Noble gases
Replies: 5
Views: 37

Lewis structures with Noble gases

can all noble gases have an expanded octect of up to 12 electrons? When I was doing lewis structures with xenon, the element has to reach 12 e- in order for the structure to be correct
Thu Nov 05, 2020 12:10 am
Forum: Lewis Structures
Topic: double bonds in Lewis structures
Replies: 2
Views: 30

double bonds in Lewis structures

how can i know which element to make a double bond within a molecule. for example, COCl2 has double bond with o and not with Cl. Is it because a bond with O results in a formal charge of 0?
Mon Nov 02, 2020 3:49 pm
Forum: Student Social/Study Group
Topic: Participation
Replies: 45
Views: 338

Re: Participation

click on your name and it should tell you how many posts you have. Just remember each week requires 5 posts so remember to account for that when calculating if you get all your participation points.
Mon Nov 02, 2020 3:46 pm
Forum: General Science Questions
Topic: Finals
Replies: 39
Views: 364

Re: Finals

Ria Nawathe 2B wrote:Will the final also be multiple choice?

I believe so especially because MT 1 and 2 were
Mon Nov 02, 2020 3:23 pm
Forum: General Science Questions
Replies: 30
Views: 344

Lavelle said it will be posted on Thursday from his office hours. Partial credit may come from these questions that are two parts. So our of the four choices, you got half of the problem right but not the other. Ex. choice a) 450nm, visible light choice b) 450nm, UV light. Certain midterm choices we...
Mon Nov 02, 2020 3:21 pm
Forum: General Science Questions
Topic: Finals
Replies: 39
Views: 364

Finals

Are finals cumulative? covering everything from midterm 1 and 2?
Thu Oct 29, 2020 10:57 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 3d and 4s state
Replies: 4
Views: 47

Re: 3d and 4s state

Does anyone know the concept of 4s being a higher energy level? I was thinking that ground states have higher energy since it is the closest to the nucleus, but why does 4s or any level higher than the ground state have the title of "higher energy level"? Is there a difference between ene...
Thu Oct 29, 2020 7:35 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations
Replies: 15
Views: 93

Re: Electron Configurations

Mary Shih 3J wrote:Should we specifiy 2pxpypx or 2p^3 for electron configurations? How should we write it for tests?

does this apply to the d or f subshell? what letters are used for those larger subshells
Thu Oct 29, 2020 7:20 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations
Replies: 15
Views: 93

Electron Configurations

Should we specifiy 2pxpypx or 2p^3 for electron configurations? How should we write it for tests?
Thu Oct 29, 2020 7:17 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 3d and 4s state
Replies: 4
Views: 47

Re: 3d and 4s state

I think I should expand on my question. If their energies are so close to each other, why are they not equal energies?
Thu Oct 29, 2020 7:13 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 3d and 4s state
Replies: 4
Views: 47

3d and 4s state

In the lecture, lavelle said something about 3d has more energy than the 4s state because the energies are so close to each other. Can someone expand on this cause Im confused as to why this is
Fri Oct 23, 2020 2:21 pm
Forum: General Science Questions
Topic: Sapling
Replies: 3
Views: 28

Sapling

Are the sapling questions now in the correct order? I know Lavelle sent an email about how the questions were randomized. Some of my questions like 17 and 18 cover quantum numbers so Im not sure which questions I should practice before the midterm.
Fri Oct 23, 2020 2:19 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Numbers
Replies: 6
Views: 35

Re: Magnetic Quantum Numbers

m sub l does not only equal l - 1. It can equal a range of values; m sub l equals 1, l-1,... -1. For example. if l equals 2, then m sub l can be equal to 2, 1, 0, -1, -2. So the m sub l number is the number it starts with and it ranges to the negative value of l? Like l=1 is starts at 1 and ends at...
Fri Oct 23, 2020 1:42 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Numbers
Replies: 6
Views: 35

Magnetic Quantum Numbers

After friday's ledture, I am still confused on how is m sub l (magnetic quantum #) equal to l-1. For example I thought subshell d or l=2 had 5 different types of orbitals. So why does l-1=m subL
Wed Oct 21, 2020 2:43 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Energy for non hydrogen atoms
Replies: 2
Views: 35

Energy for non hydrogen atoms

Should we be comfotable finding energy levels for non hydrogen atoms? For example: Calculate the wavelength of the photon emitted during the transition from the first excited state to the ground-state for the doubly ionized lithium atom, Li^2+. I know this requires a different equation from e=-hR/n^...
Wed Oct 21, 2020 2:28 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Which Equation should we use?
Replies: 3
Views: 41

Which Equation should we use?

I know there are two forms of the indeterminacy equation: deltap deltax= h/4pi and deltap deltax=0.5h(bar) where hbar is h/2pi. which one should we be using If there is a preference to one equation.
Thu Oct 15, 2020 1:50 pm
Forum: Properties of Light
Topic: Textbook 1A #15
Replies: 4
Views: 68

Re: Textbook 1A #15

The ultraviolet spectrum of atomic hydrogen is the Lyman series, so n(1)=1. By using Rydberg's equation you can solve for n(2). Are the Lyman, Balmer, and Paschen series only with respect to hydrogen? Would there be a case where initial n of hydrogen is equal to 2 (balmer series)? In this case, why...
Thu Oct 15, 2020 1:28 pm
Forum: Properties of Light
Topic: Textbook 1A #15
Replies: 4
Views: 68

Textbook 1A #15

In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energy that leads to this spectral line. How do I find the initial and final energy level just from a wavelength? D...
Thu Oct 15, 2020 12:52 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Equation
Replies: 3
Views: 56

Heisenberg Equation

-In the Heisenberg questions, after finding delta p from the equation, do u always have to plug it back into delta p=mV to find uncertainty in position?
Thu Oct 15, 2020 12:49 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Equation Delta X
Replies: 2
Views: 43

Equation Delta X

I am still a little confused as to what delta x means in the Heisenberg Equation. Can some explain what it means in the context of the equation and the experiment?
Tue Oct 13, 2020 9:53 pm
Forum: Properties of Light
Topic: Photoelectric spectrum
Replies: 24
Views: 163

Photoelectric spectrum

I know the textbook questions asked questions regarding which wavelength corresponds to a microwave, visible light, y rays etc. Does anyone know If we should be memorizing the entire electromagnetic spectrum?
Sat Oct 10, 2020 12:38 am
Forum: Properties of Light
Topic: Post assessment question #30
Replies: 1
Views: 24

Post assessment question #30

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.

What is the frequency of the incident light on the sodium metal surface? I got 2.27x10^38 and its marked wrong.

Is this a mistake or is my answer wrong?
Fri Oct 09, 2020 8:36 pm
Forum: Properties of Light
Topic: photoelectric effect
Replies: 5
Views: 74

Re: photoelectric effect

That is a great question. In the photoelectric experiment they observed that increasing the intensity of the light did not eject electrons and they concluded that light was not acting like a wave. Instead it was acting like it was made of individual photons, where the individual photon's energy mus...
Fri Oct 09, 2020 8:06 pm
Forum: Properties of Light
Topic: photoelectric effect
Replies: 5
Views: 74

photoelectric effect

If long wavelength light is not ejecting electrons from a metal surface will increasing the intensity of the light result in electrons being ejected? Justify your answer. No, because in this experiment light is not acting like a wave. If light were acting like a wave then the intensity would be prop...
Wed Oct 07, 2020 1:43 am
Forum: Molarity, Solutions, Dilutions
Topic: Fundamentals M25
Replies: 2
Views: 41

Fundamentals M25

Practitioners of the branch of alternative medicine known as homeopathy claim that very dilute solutions of substances can have an effect. Is the claim plausible? To explore this question, suppose that you prepare a solution of a supposedly active substance, X, with a molar concentration of 0.10 mol...
Tue Oct 06, 2020 9:57 pm
Forum: SI Units, Unit Conversions
Topic: Formula Units
Replies: 9
Views: 107

Re: Formula Units

Do you calculate formula units the same way we calculate number of atoms in a molecule from molar mass and avogadros number?
Tue Oct 06, 2020 9:47 pm
Forum: SI Units, Unit Conversions
Topic: Formula Units
Replies: 9
Views: 107

Formula Units

Epsom salts consist 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 5.15 g?

Can someone explain what formula units are?
Mon Oct 05, 2020 8:00 pm
Forum: Limiting Reactant Calculations
Topic: Fundamentals M19
Replies: 5
Views: 35

Fundamentals M19

A stimulant in coffee and tea is caffeine, a substance of molar mass 194g/mol. When 0.376 g of caffeine was burned, 0.682 g of carbon dioxide, 0.174 g of water, and 0.110 g of nitrogen were formed. Determine the empirical and molecular formulas of caffeine, and write the equation for its combustion....