Search found 87 matches

by Tracy Tolentino_2E
Sun Jan 19, 2020 11:46 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kw
Replies: 2
Views: 9

Kw

When do we use the Kw value?
by Tracy Tolentino_2E
Sun Jan 19, 2020 11:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q
Replies: 6
Views: 10

Re: Q

Q is the reaction quotient and is calculated at any time during a reaction. Q will change as time passes. Q and K are similar except that K is the value when the reaction is at equilibrium. If Q>K, the reverse reaction is favored, and if Q<K, the forward reaction is favored. IF Q=K, the both reverse...
by Tracy Tolentino_2E
Sun Jan 19, 2020 11:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5% rule
Replies: 2
Views: 7

Re: 5% rule

If the change value, x, divided over the initial concentration is less than 5% of that initial, it's safe to assume that the change was negligible. This is to affirm that when we have a quadratic equation, we don't have to do the quadratic formula to solve for x.
by Tracy Tolentino_2E
Sun Jan 19, 2020 11:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Combining Reactions
Replies: 3
Views: 12

Re: Combining Reactions

If both of those reactions are combined and form the third reaction, then we can add them. As a result, the K values can be multiplied together to find the K value of the third reaction.
by Tracy Tolentino_2E
Sun Jan 19, 2020 11:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ice Tables
Replies: 4
Views: 14

Ice Tables

When do we use ICE tables? I assumed it was when we had to find concentrations of the products, given K and the initial concentration(s).
by Tracy Tolentino_2E
Sun Jan 19, 2020 11:29 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier Principle
Replies: 4
Views: 24

Le Chatelier Principle

Why does only a change in temperature affect K and not pressure or concentration? How does Le Chatelier principle apply to this if the principle sees the direction of the reaction due to changes?
by Tracy Tolentino_2E
Sun Jan 19, 2020 11:02 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pKa and pH
Replies: 1
Views: 16

pKa and pH

Is there a relationship between pKa and pH? If so, what is it?
by Tracy Tolentino_2E
Sun Jan 12, 2020 3:33 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5J.13
Replies: 4
Views: 20

Re: 5J.13

Do we not have to calculate anything?
by Tracy Tolentino_2E
Sun Jan 12, 2020 3:09 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5J.13
Replies: 4
Views: 20

5J.13

A gaseous mixture consisting of 2.23 mmol N2 and 6.69 mmol H2 in a 500.-mL container was heated to 600. K and allowed to reach equilibrium. Will more ammonia be formed if that equilibrium mixture is then heated to 700. K? For N2(g) + 3H2(g) <---> 2NH3(g), K=1.7x10^-3 at 600.K and 7.8x10^-5 at 700. K...
by Tracy Tolentino_2E
Sun Jan 12, 2020 2:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE tables
Replies: 1
Views: 15

ICE tables

When doing the ICE tables, do we only use concentration of the reactions? What if we are given partial pressures?
by Tracy Tolentino_2E
Thu Jan 09, 2020 1:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G. 3
Replies: 5
Views: 32

5G. 3

Write the expression for K for each of the following reactions: (A) 2C2H4(g) + O2(g) + 4HCl(g) <—> 2C2H4Cl2(g) + 2H2O(g) Why is it that we write K for this problem using pressure yet for 5G.7 where we essentially do the same thing after balancing the reaction, they use Kc for the problem. Which is c...
by Tracy Tolentino_2E
Wed Jan 08, 2020 10:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Liquids in Equilibrium Constant
Replies: 3
Views: 26

Liquids in Equilibrium Constant

Why are liquids not included in the equilibrium constant? Do we only included gases within K?
by Tracy Tolentino_2E
Mon Jan 06, 2020 4:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant
Replies: 4
Views: 31

Equilibrium Constant

What does the value of K supposed to tell us about the reaction? And what does strongly favor mean within equilibrium?
by Tracy Tolentino_2E
Sun Dec 08, 2019 3:08 am
Forum: Naming
Topic: NH4[PtCl3(NH3)]
Replies: 5
Views: 39

NH4[PtCl3(NH3)]

The name is Ammonium amminetrichloridoplatinate(II). Why is it platinate and not platinum?
by Tracy Tolentino_2E
Sun Dec 08, 2019 2:42 am
Forum: Naming
Topic: [Fe(OH)(OH2)5]Cl2
Replies: 3
Views: 39

[Fe(OH)(OH2)5]Cl2

So the name for [Fe(OH)(OH2)5]Cl2 is pentaaquahydroxidoiron(III) chloride. But how did they get the charge on iron? And why is it chloride if there are two chloride, shouldn't it be dichloride?
by Tracy Tolentino_2E
Sun Dec 08, 2019 2:27 am
Forum: Naming
Topic: Polydentate
Replies: 2
Views: 27

Polydentate

How can you tell a ligand is a polydentate? And what are examples of anionic ligands, how are they different from anions?
by Tracy Tolentino_2E
Sat Dec 07, 2019 8:37 pm
Forum: Lewis Acids & Bases
Topic: Bronsted vs Lewis Acid
Replies: 1
Views: 26

Bronsted vs Lewis Acid

How can you tell if an acid is a Bronsted acid or a lewis acid? Can an acid be considered both or does it have to be or the other?
by Tracy Tolentino_2E
Sun Dec 01, 2019 11:35 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Oxoacids
Replies: 1
Views: 14

Oxoacids

Why are oxoacids more readily lose H+ ions? And what are "oxoacids"?
by Tracy Tolentino_2E
Sun Dec 01, 2019 11:28 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: relationship between pH and pOH
Replies: 2
Views: 16

relationship between pH and pOH

Can we calculate the pOH from pH? What is their relationship?
by Tracy Tolentino_2E
Sun Dec 01, 2019 11:27 pm
Forum: Amphoteric Compounds
Topic: Amphoteric compounds
Replies: 1
Views: 19

Amphoteric compounds

What are amphoteric compounds? What does it mean "amphoteric oxides"?
by Tracy Tolentino_2E
Sun Dec 01, 2019 11:25 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Anion stability
Replies: 6
Views: 52

Anion stability

How do we know if an anion is stable? And what is Ka value?
by Tracy Tolentino_2E
Sun Dec 01, 2019 11:23 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pOH
Replies: 3
Views: 22

pOH

When do we need to find pOH and why would be beneficial to find it?
by Tracy Tolentino_2E
Mon Nov 25, 2019 12:01 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: What is a chelating complex?
Replies: 1
Views: 12

Re: What is a chelating complex?

Yes, it is essentially a complex that contains the ligand and forms a ring of atoms that includes the central metal atom.
by Tracy Tolentino_2E
Sun Nov 24, 2019 11:59 pm
Forum: Naming
Topic: -dentate
Replies: 1
Views: 29

Re: -dentate

Polydentates refers to a ligand molecule with more than one donor atom.
Bidentates have two atoms that can bond to a central atom or ion.
Ambidentate are like monodentates where they have one atom that can bond to a central atom or ion, but can do it at two possible locations.
by Tracy Tolentino_2E
Sun Nov 24, 2019 11:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape of carbon Dioxide
Replies: 10
Views: 39

Re: Molecular shape of carbon Dioxide

It is linear as it has 16 valence electrons. The carbon does not have lone pairs and forms double bonds with the oxygens. So it would be AX2.
by Tracy Tolentino_2E
Sun Nov 24, 2019 11:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw shape
Replies: 5
Views: 25

Re: Seesaw shape

Seesaw shape occurs when you have 4 atoms surrounding the central atom along with a lone pair. It would occur because during the trigonal bipyramidal, we would have three atoms in the planar, 120 degrees apart, and then an atom on the top and bottom of the central atom, making them 90 degrees from t...
by Tracy Tolentino_2E
Sun Nov 24, 2019 11:37 pm
Forum: Hybridization
Topic: hybridization
Replies: 3
Views: 31

Re: hybridization

It means that the orbitals are not completely an s,p,d orbital. It is a mix of them, with a different energy and shape.
by Tracy Tolentino_2E
Sun Nov 24, 2019 11:34 pm
Forum: Hybridization
Topic: 2F.5
Replies: 3
Views: 24

Re: 2F.5

a) sp
b) sp2
c) sp3
d) sp3
by Tracy Tolentino_2E
Sun Nov 24, 2019 11:18 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Cisplatin and Transplatin
Replies: 2
Views: 20

Cisplatin and Transplatin

How does Cisplatin stop cell division? Why doesn't Transplatin have the same effect when forming a coordinate compound with DNA?
by Tracy Tolentino_2E
Sun Nov 17, 2019 11:56 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape vs Electron Geometry
Replies: 4
Views: 29

Re: Molecular Shape vs Electron Geometry

Molecular shape excludes the electron lone pairs while electron geometry involves them.
by Tracy Tolentino_2E
Sun Nov 17, 2019 11:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 9
Views: 40

Re: Bond Angles

We got to memorize the basic angles like 90, 120, and 180 and we should be able to predict if they are greater than or less than these angles. We don’t need to know the unique ones. I just imagine what the molecule looks like in a 3D setting based on the name of the shape.
by Tracy Tolentino_2E
Sun Nov 17, 2019 11:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape
Replies: 1
Views: 22

Re: Molecular Shape

Lone pairs aren’t considered in identifying a molecules’ shape because they are not bonded to the atom. When lone pairs are around the central atom, the atoms bonded to it are forced to move due to the electron repulsion from the lone pairs.
by Tracy Tolentino_2E
Sun Nov 17, 2019 11:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: IMF
Replies: 3
Views: 23

Re: IMF

Ion- dipole is between an ion and a polar molecule while dipole-dipole is between polar molecules.
by Tracy Tolentino_2E
Sun Nov 17, 2019 11:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Repulsion Strength
Replies: 5
Views: 33

Repulsion Strength

Why is the electron repulsion strength stronger for lone-lone PR> lone-bonding PR> bonding-bonding PR?
by Tracy Tolentino_2E
Sun Nov 17, 2019 11:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Notation
Replies: 4
Views: 28

VSEPR Notation

Can someone re-explain how to write VSEPR notation? I did not write the notation at all during my notes.
by Tracy Tolentino_2E
Sun Nov 10, 2019 11:39 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: London Dispersion Forces
Replies: 1
Views: 17

Re: London Dispersion Forces

London dispersion forces are the weakest of the intermolecular forces. I think they take priority in larger atoms because of more surface area to distort the electrons.
by Tracy Tolentino_2E
Sun Nov 10, 2019 11:36 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: What’s the Difference
Replies: 6
Views: 73

Re: What’s the Difference

Polarizability is the tendency by the anion to be polarized by the cation and polarizing refers to the power of the cations to distort the electrons of the anion.
by Tracy Tolentino_2E
Sun Nov 10, 2019 11:33 pm
Forum: Bond Lengths & Energies
Topic: Rankings
Replies: 2
Views: 23

Re: Rankings

There are bonds within a molecule like covalent and ionic bonds and bonds between molecules like london dispersion forces and hydrogen bonding. The intramolecular (covalent/ionic) are stronger than the latter (intermolecular).
by Tracy Tolentino_2E
Sun Nov 10, 2019 11:31 pm
Forum: Dipole Moments
Topic: Dipole Moment vs Interactions
Replies: 2
Views: 19

Dipole Moment vs Interactions

How does a dipole moment differ from a dipole interaction? Is it possible for a molecule to have both? And also, what is ion-ion dipole?
by Tracy Tolentino_2E
Sun Nov 10, 2019 11:18 pm
Forum: Dipole Moments
Topic: H Bonding
Replies: 4
Views: 27

H Bonding

Does H bonding only work with Fluorine, Oxygen, and Nitrogen? Why only them and not other elements? Why is this type of bonding not as strong as covalent bonding?
by Tracy Tolentino_2E
Sun Nov 10, 2019 11:14 pm
Forum: Quantum Numbers and The H-Atom
Topic: The spin of a quantum number
Replies: 6
Views: 45

Re: The spin of a quantum number

You can't really tell. You can say it's positive or negative but the other electrons in the other subshells have to have the same spin.
by Tracy Tolentino_2E
Sun Nov 10, 2019 11:13 pm
Forum: Dipole Moments
Topic: Shape of Molecule
Replies: 2
Views: 13

Shape of Molecule

How does the shape of the molecule affect the strength of the dipole interactions? And why would it matter?
by Tracy Tolentino_2E
Sun Nov 10, 2019 11:06 pm
Forum: Dipole Moments
Topic: Dipole Moment
Replies: 6
Views: 33

Dipole Moment

How do we know if a molecule has a dipole moment? And why does the arrow have to point to the lowercase delta positive?
by Tracy Tolentino_2E
Sun Nov 03, 2019 11:46 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent and Ionic Bonds
Replies: 6
Views: 38

Covalent and Ionic Bonds

Can someone explain the concept of a molecule having both ionic and covalent characters. How do we determine which is more?
by Tracy Tolentino_2E
Sun Nov 03, 2019 11:38 pm
Forum: Resonance Structures
Topic: Drawing Resonance Structures on Test?
Replies: 4
Views: 31

Re: Drawing Resonance Structures on Test?

We have to indicate that it is the hybrid of all the resonance structures.
by Tracy Tolentino_2E
Sun Nov 03, 2019 11:37 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Best Formal Charge
Replies: 7
Views: 82

Best Formal Charge

How do we know if the structure is the best if the formal charge for all the atoms are not 0? Like is it better for the outer atoms to have a formal charge of 0 while the central atom is not 0 or would the opposite be better?
by Tracy Tolentino_2E
Sun Nov 03, 2019 11:33 pm
Forum: DeBroglie Equation
Topic: Dino Nuggets 6a
Replies: 1
Views: 63

Re: Dino Nuggets 6a

The mass of the atom would be the 3.157 g/mol but since it is in atom, we would use Avogadro's number to make the units kg/atom.
Then we would use De Broglie's equation to solve for frequency since they give us velocity and mass.
by Tracy Tolentino_2E
Sun Nov 03, 2019 11:30 pm
Forum: Bond Lengths & Energies
Topic: Short bond lengths vs long bond lengths
Replies: 6
Views: 47

Re: Short bond lengths vs long bond lengths

Shorter bond lengths are stronger than longer bond lengths because it means that the nucleus of both atoms are pulling the electrons closer to themselves. It would take more energy to break those bonds.
by Tracy Tolentino_2E
Sun Nov 03, 2019 11:28 pm
Forum: Lewis Structures
Topic: double bonding with halogens
Replies: 3
Views: 29

Re: double bonding with halogens

No because halogens only want one more electron. So by having a single bond, they fulfill the octet rule.
by Tracy Tolentino_2E
Sun Nov 03, 2019 11:24 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configuration
Replies: 3
Views: 28

Electron Configuration

When finding the electron configuration of an ion, why do we remove electrons from the highest orbital first?
by Tracy Tolentino_2E
Sun Nov 03, 2019 11:22 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 3
Views: 32

Ionization Energy

Why does ionization energy and electron affinity increase across the period and increase up a group? And what is the difference between electron affinity and ionization energy?
by Tracy Tolentino_2E
Sun Nov 03, 2019 11:06 pm
Forum: Resonance Structures
Topic: Unequal Contribution
Replies: 3
Views: 54

Unequal Contribution

How do you draw the resonance structure for a molecule or compound that don't contribute equally?
by Tracy Tolentino_2E
Sun Oct 27, 2019 8:07 pm
Forum: Lewis Structures
Topic: Lone Pairs
Replies: 12
Views: 58

Re: Lone Pairs

Well, generally most atoms wants to follow the octet rule. It depends on the total number of valence electrons, because you got to make sure the central atom has its' octet, then you add the lone pairs to the outside atoms. If you realize that there isn't enough for the outside, then you create the ...
by Tracy Tolentino_2E
Sun Oct 27, 2019 8:02 pm
Forum: Ionic & Covalent Bonds
Topic: Metalloids
Replies: 5
Views: 35

Metalloids

Do metalloids form ionic bonds or covalent bonds?
by Tracy Tolentino_2E
Sun Oct 27, 2019 7:57 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 4f Subshell Clarification
Replies: 3
Views: 25

Re: 4f Subshell Clarification

Yes, the 4f subshell fills up before the 5d subshell. This is because of Aufbau's principle which says that electrons fill up the lowest energy levels first before occupying higher levels.
by Tracy Tolentino_2E
Sun Oct 27, 2019 7:51 pm
Forum: Lewis Structures
Topic: Expanded valence shells
Replies: 3
Views: 31

Expanded valence shells

So according to Professor Lavelle, atoms in period 3 or higher have d-orbitals in valence shell that can accommodate additional electrons. Does that mean all the elements from period 3 onward are exceptions to this octet rule? And can someone explain the phosphorus pentachloride example? How does ph...
by Tracy Tolentino_2E
Sun Oct 27, 2019 7:45 pm
Forum: Trends in The Periodic Table
Topic: Electron affinity equation
Replies: 1
Views: 16

Re: Electron affinity equation

It is because electron affinity is the energy released when an electron is added to a neutral atom. By subtracting the energy of the neutral atom from the energy of the final, we are essentially finding the energy released, ie the electron affinity.
by Tracy Tolentino_2E
Sun Oct 27, 2019 7:39 pm
Forum: Octet Exceptions
Topic: Exceptions
Replies: 3
Views: 42

Exceptions

Can someone explain why H, He, Li and Be are exceptions to the octet rule? And why we choose the atom with the least ionization energy as the central atom?
by Tracy Tolentino_2E
Sun Oct 27, 2019 7:34 pm
Forum: Bond Lengths & Energies
Topic: Single bond vs double bond
Replies: 14
Views: 122

Single bond vs double bond

So during the lecture on Friday, Professor Lavelle drew the structures of Benzene and I was wondering what he meant when he wrote 1.34 Angstroms next to a double bond between C-C, and1.54 Angstroms for a single bond. What do these numbers describe? And what does he mean that electrons in resonance s...
by Tracy Tolentino_2E
Sun Oct 27, 2019 7:27 pm
Forum: Ionic & Covalent Bonds
Topic: Homework
Replies: 13
Views: 109

Re: Homework

I think so.
by Tracy Tolentino_2E
Sun Oct 20, 2019 11:16 pm
Forum: Einstein Equation
Topic: 1B. 5
Replies: 4
Views: 57

Re: 1B. 5

After converting to Joules, I used Planck's equation to find the frequency. From frequency, I used the speed of light equation to find wavelength.
by Tracy Tolentino_2E
Sun Oct 20, 2019 11:11 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Applying Pauli Exclusion Principle and Hund's Rule
Replies: 5
Views: 36

Re: Applying Pauli Exclusion Principle and Hund's Rule

So for Pauli's Exclusion Principle, it states no more than 2 electrons per orbital and that the two electrons must be spin paired. In electron configuration, the quantum numbers (n,l,m(l),m(s)) matter as there are four main orbitals: s,p,d,f n is the principle quantum number and determines the size ...
by Tracy Tolentino_2E
Sun Oct 20, 2019 10:55 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Ordering for different orbitals
Replies: 3
Views: 21

Re: Ordering for different orbitals

The order doesn't matter because they have the same energy and orbital.
by Tracy Tolentino_2E
Sun Oct 20, 2019 10:54 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Excited State
Replies: 3
Views: 33

Re: Excited State

You can tell if an atom is in an excited state if it doesn't follow the rules we have: Aufbau's principle, Hund's Rule, and Pauli's Exclusion Principle. We first have to know what the electron configuration of the atom in its' ground state. Ground states is when electrons are in the lowest energy le...
by Tracy Tolentino_2E
Sun Oct 20, 2019 10:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: What is electron configuration?
Replies: 3
Views: 30

Re: What is electron configuration?

Electron configuration is the way we distribute electrons of an atom in an orbital. There are four main shapes of orbitals which we call s,p,d,f.
by Tracy Tolentino_2E
Sun Oct 20, 2019 10:38 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1D.17
Replies: 1
Views: 17

Re: 1D.17

Magnetic quantum numbers is denoted by the letter m(l) and tells us the number of orbitals in a subshell along with their orientation. a)6p so we know p has an angular quantum number of 1 and since m(l) depends on l, we get possible values of -1,0,+1 b)3d d orbital has l = 2 so we get possible value...
by Tracy Tolentino_2E
Sun Oct 20, 2019 10:24 pm
Forum: Student Social/Study Group
Topic: Study Group Fall 2019
Replies: 32
Views: 1401

Re: Study Group Fall 2019

I'll join too!!
by Tracy Tolentino_2E
Sun Oct 20, 2019 10:23 pm
Forum: DeBroglie Equation
Topic: Conversion Units for 1B.21
Replies: 3
Views: 26

Re: Conversion Units for 1B.21

1 oz = 28.3 g
For miles per hour, there's 3600 sec in 1 hr and 1 km is 0.6214 miles. 1000 m = 1 km
by Tracy Tolentino_2E
Sun Oct 13, 2019 8:20 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: HW question 1A.15
Replies: 2
Views: 42

Re: HW question 1A.15

We know that the ultraviolet region of hydrogen has an energy level of n=1. With 102.6 nm we can find the frequency using v=speed of light/wavelength 2.998*10^8 m.s^-1 / (102.6*10^-9 m) = 2.922*10^15 s^-1 We then use the Rydberg formula, so v=R((1/n1 ^2) - (1/n2 ^2)) 1/n2 ^2 = 1- ((2.922*10^15 s^-1)...
by Tracy Tolentino_2E
Sun Oct 13, 2019 8:09 pm
Forum: Properties of Electrons
Topic: Photoelectric Effect
Replies: 3
Views: 28

Re: Photoelectric Effect

The results of the photoelectric experiment was surprising because they thought increasing the light intensity would increase the number of electrons being ejected. But this turned to be untrue because the light intensity only affected the number of protons, but not the kinetic energy.
by Tracy Tolentino_2E
Sun Oct 13, 2019 8:04 pm
Forum: Photoelectric Effect
Topic: Photoelectric experiment
Replies: 3
Views: 33

Re: Photoelectric experiment

He thought that increasing the light intensity would increase the number of electrons being ejected. This wasn't the case because high light intensity only increased the number of photons, but did nothing to the kinetic energy of the photoelectrons. The energy of the photons stayed the same and prob...
by Tracy Tolentino_2E
Sun Oct 13, 2019 7:53 pm
Forum: DeBroglie Equation
Topic: De Broglie's Equation
Replies: 17
Views: 95

Re: De Broglie's Equation

De Broglie's equation is used for objects that has mass and behaves similarly to a wave. It also require momentum or velocity. Light theoretically doesn't have mass so the equation can't be used.
by Tracy Tolentino_2E
Sun Oct 13, 2019 7:46 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 1A.11
Replies: 1
Views: 37

1A.11

"In the spectrum of atomic hydrogen, several lines are generally classified together as belonging to a series. What is common to the lines within a series that make grouping them together logical?" I understand that they are talking about energy levels, but what is an energy level? The sol...
by Tracy Tolentino_2E
Sun Oct 13, 2019 7:30 pm
Forum: Administrative Questions and Class Announcements
Topic: test 1 grades
Replies: 2
Views: 33

Re: test 1 grades

I'm pretty sure it differs between TAs. My TA told us we would get our test back the following week.
by Tracy Tolentino_2E
Sun Oct 13, 2019 7:28 pm
Forum: Properties of Light
Topic: Angtrom Question
Replies: 1
Views: 24

Re: Angtrom Question

1 Angstrom = 10^-10 m
1 m = 10^9 nm

So 500 nm / 10^9 nm = 10^-7 m
10^-7 m / 10^-10 m is 5000 Angstrom
by Tracy Tolentino_2E
Sun Oct 13, 2019 7:15 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: energy levels
Replies: 1
Views: 17

energy levels

Can someone explain this equation to me

V=R(1/n^2 - 1/n^2) where the n are different energy levels I think.
What is this equation used for?
by Tracy Tolentino_2E
Sun Oct 13, 2019 7:08 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Textbook Problem- 1B.19
Replies: 1
Views: 16

Re: Textbook Problem- 1B.19

We would use De Broglie's equation wavelength=Planck's constant/(mass of particle x velocity). Planck's constant: 6.626 * 10^-34 J.s mass of proton: 1.673 * 10^-27 kg mass of neutron: 1.675 * 10^-27 kg velocity: 2.75 * 10^5 m/s wavelength of proton = 6.626 * 10^-34 J.s / ((1.673 * 10^-27 kg) * (2.75...
by Tracy Tolentino_2E
Sun Oct 13, 2019 5:57 pm
Forum: Properties of Light
Topic: Question 1A.3 part c
Replies: 1
Views: 18

Re: Question 1A.3 part c

They are talking about the slope of the wavelength at a certain point. Since we know that wavelength x frequency = speed of light, decreasing the frequency means wavelength increases. By wavelength increasing/enlarging, the slope of the wave decreases.
by Tracy Tolentino_2E
Fri Oct 04, 2019 7:05 am
Forum: SI Units, Unit Conversions
Topic: Homework: L35
Replies: 2
Views: 43

Re: Homework: L35

You have to take in account the coefficients of the reactions. 1 mole of Fe3Br8 equals 8 moles of NaBr but then you have to do 1 mole of Fe3Br8 to 3 moles FeBr2. From FeBr2 to Fe, it’s a 1:1 ratio. If you don’t do the second conversion of moles, you’re ignoring the ratio.
by Tracy Tolentino_2E
Thu Oct 03, 2019 6:48 pm
Forum: Limiting Reactant Calculations
Topic: M19
Replies: 3
Views: 65

Re: M19

You would put CO2, H2O, and N2 to the product side because it stated all three were formed. The balanced equation is
2C8H10N4O2(s) + 19O2(g) --> 16CO2(g) + 10 H2O(l) + 4N2(g)
by Tracy Tolentino_2E
Thu Oct 03, 2019 6:31 pm
Forum: Molarity, Solutions, Dilutions
Topic: F. 13 Empirical & Molecular Formula
Replies: 2
Views: 49

Re: F. 13 Empirical & Molecular Formula

So to do this problem, you would need to find the mass percent of phosphorus. Given that we have the grams of phosphorus and the grams of the compound, we can do (4.14 g / 27.8 g) x 100 to get the mass percent, 14.9%. In 100 g of the compound, P would be 14.9 g and we can find Cl to be 85.1 g. To fi...
by Tracy Tolentino_2E
Mon Sep 30, 2019 3:19 pm
Forum: Empirical & Molecular Formulas
Topic: Fundamentals L.39
Replies: 2
Views: 46

Fundamentals L.39

"A 1.50 g sample of metallic tin was placed in a 26.45 g crucible and heated until all the tin had reacted with the oxygen in the air to form an oxide. The crucible and product together were found to weigh 28.35 g. (a) What is the empirical formula of the oxide? (b) Write the name of the oxide....
by Tracy Tolentino_2E
Mon Sep 30, 2019 3:08 pm
Forum: Molarity, Solutions, Dilutions
Topic: Homework problem E23
Replies: 5
Views: 61

Re: Homework problem E23

The chemical equation is written as Cu2+ + 2Br- --> CuBr2. So the ratio is 1 mol of Cu2+ to 1 mol CuBr2.
by Tracy Tolentino_2E
Mon Sep 30, 2019 2:51 pm
Forum: Molarity, Solutions, Dilutions
Topic: HW Fundamentals E15- what is 34.02 grams?
Replies: 3
Views: 54

Re: HW Fundamentals E15- what is 34.02 grams?

34.02 g is the molar mass of the (OH)2 portion of M(OH)2. By subtracting 34.02 g from 74.10 g, we know the molar mass of the metal, and can figure out what the metal is.

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