Search found 62 matches

by 504939134
Thu Jan 16, 2020 11:18 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Combing kA and kB
Replies: 2
Views: 13

Combing kA and kB

Can anyone explain why we need to multiply the kA and kB in order the get the Kw for weak acid and base reactions?
by 504939134
Thu Jan 16, 2020 11:15 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gas
Replies: 7
Views: 28

Re: Inert Gas

Inert gases are those gases that do not react, and therefore do not change the reaction, therefore you can use noble gases as an example as they usually do not react with other elements.
by 504939134
Thu Jan 16, 2020 11:13 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Kw
Replies: 16
Views: 52

Re: Kw

They both essentially mean the same thing, and you can use them interchangeably.
by 504939134
Thu Jan 16, 2020 9:30 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic
Replies: 5
Views: 17

Exothermic

Why is energy released as new bonds are formed?
by 504939134
Thu Jan 16, 2020 9:20 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Endothermic vs exothermic
Replies: 4
Views: 26

Endothermic vs exothermic

Can someone please explain why : 1. If a reaction requires Heat, (is endothermic) while forming products, then heating will favor P (product) formation when additional heat is used. 2. If a reaction gives off heat, (is exothermic) while forming products, then heating will favor R formation when addi...
by 504939134
Sun Jan 12, 2020 10:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K
Replies: 10
Views: 38

Re: K

Kc is the equilibrium constant used for aqueous solutions, because they have concentration values. Kp is the equilibrium constant for gases, since they have partial pressures.
by 504939134
Thu Jan 09, 2020 4:57 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G.11
Replies: 4
Views: 17

5G.11

For question 5G.11 it asks to write the reaction quotient for the reactions given. I know that to calculate the Q you do the same thing as when you are calculating for K, but in the answer key it states that the Q= 1/(PBCl3)^2.
Why would it not be (PB2Cl4)(PHg2Cl2)/(Pcl3)^2(PHg)^2?
by 504939134
Thu Jan 09, 2020 2:27 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G. 3
Replies: 5
Views: 32

Re: 5G. 3

Because it contains aqueous solution we would use Kc instead of Kp which is just for gases.
by 504939134
Thu Jan 09, 2020 2:25 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q vs K
Replies: 8
Views: 45

Re: Q vs K

Q is not at equilibrium, it is just products over reactants at any given time during the reaction. K is the equilibrium constant of the products over her reactants.
by 504939134
Thu Jan 09, 2020 2:22 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Re: Q and Ke: Small K value and Large K value
Replies: 7
Views: 23

Re: Q and Ke: Small K value and Large K value

The reaction quotient is the amount of products over reactants at any time during the Rxn, it is calculated the same way as K but it is not at equilibrium.
by 504939134
Sun Dec 08, 2019 7:41 pm
Forum: Student Social/Study Group
Topic: Class Grading
Replies: 35
Views: 490

Re: Class Grading

I hope this is true! But yeah I have heard that his final grades are curved but test aren’t.
by 504939134
Sun Dec 08, 2019 12:26 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Ph and poH of weak acids
Replies: 8
Views: 44

Ph and poH of weak acids

Will we be asked to measure the ph and PoH of weak acids and bases?
by 504939134
Sun Dec 08, 2019 12:25 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: CO2 in blood
Replies: 1
Views: 19

CO2 in blood

So if there is a lot of co2 in the blood it will cause there to be more carbonic acid in the blood which in turn creates more H30+ molecules increasing the pH?
by 504939134
Sat Dec 07, 2019 4:20 pm
Forum: Identifying Acidic & Basic Salts
Topic: Titration
Replies: 1
Views: 18

Titration

Does anyone know what we will have to know about titrations? Or will that not be on the final?
by 504939134
Sat Dec 07, 2019 4:18 pm
Forum: Identifying Acidic & Basic Salts
Topic: 6D.11
Replies: 1
Views: 27

6D.11

For part a in 6D. 11 it asks whether an aqueous solution of each of the following salts has a pH equal to, greater than or less than 7. How would you determine this?
by 504939134
Sun Dec 01, 2019 11:02 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acting as a base
Replies: 1
Views: 19

Acting as a base

Can any biological compound with a lone pair act as a base? Or is this only true for Nitrogen?
by 504939134
Sun Dec 01, 2019 11:00 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Use of Bronsted or Lewis Definitions
Replies: 7
Views: 39

Re: Use of Bronsted or Lewis Definitions

You can use either one, but for now I would use the bronsted definition as it mentions protons which is what we are focusing on in this section.
by 504939134
Sun Dec 01, 2019 10:58 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Amphoteric compounds
Replies: 4
Views: 28

Amphoteric compounds

What are amphoteric compounds and why are they important? Would h20 be considered an amphoteric compound?
by 504939134
Sun Dec 01, 2019 10:56 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Difference between weak acids/bases and strong acids/bases
Replies: 6
Views: 34

Re: Difference between weak acids/bases and strong acids/bases

Strong acids and bases will fully ionize and disassociate while weak acids and bases will not fully ionize. Strong acids will produce more photons in solutions than weak acids.
by 504939134
Sun Dec 01, 2019 10:54 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acids Vs. Bases
Replies: 11
Views: 58

Re: Acids Vs. Bases

I like to remember that if it is an acid it will donate protons, it is a proton donator. If it is a base it will be a proton acceptor.
by 504939134
Sun Nov 24, 2019 10:52 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Transition metals
Replies: 1
Views: 17

Transition metals

Are only transition metals in the d block able to form ligand complexes?
by 504939134
Sun Nov 24, 2019 10:49 pm
Forum: Naming
Topic: Trans and Cis
Replies: 8
Views: 49

Re: Trans and Cis

Yes, whenever you see that there are the same two molecules on the same side you will know it is cis, and if you see them on opposite sides it is trans.
by 504939134
Sun Nov 24, 2019 10:43 pm
Forum: Hybridization
Topic: Shapes
Replies: 3
Views: 24

Re: Shapes

Specific shapes will tell you the amount of electronic density that is found. For example for Tetrahedral you have 4 regions of electron density regions, which means there will be 4 hybridization orbitals which is sp3.
by 504939134
Sun Nov 24, 2019 10:39 pm
Forum: Hybridization
Topic: sigma or pi?
Replies: 20
Views: 102

Re: sigma or pi?

Whenever you see a single bond know that it is sigma. When you see a double or triple bond one will be sigma and the other two will be pi bonds. Sigma bonds are single covalent bonds.
by 504939134
Sun Nov 24, 2019 10:38 pm
Forum: Hybridization
Topic: Hybridization number
Replies: 3
Views: 25

Hybridization number

Will the hybridization orbitals always be equal to the number of electronic density regions? If yes, why?
by 504939134
Thu Nov 21, 2019 9:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Week 8 homework
Replies: 2
Views: 49

Week 8 homework

Does anyone know if we can turn in homework this week on molecular structures since we have the test 2 on it this week?
by 504939134
Sun Nov 17, 2019 10:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Double and triple bonds
Replies: 4
Views: 25

Double and triple bonds

I know that double and triple bonds are not considered double or triple regions of electron density, but why? Why do we not count them as such?
by 504939134
Sun Nov 17, 2019 10:37 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 7
Views: 45

Re: Bond Angles

Due to lone pair repulsion, the more lone pairs there are the more repulsion there will be.
by 504939134
Sun Nov 17, 2019 10:33 pm
Forum: Hybridization
Topic: Test 2
Replies: 11
Views: 71

Re: Test 2

Dr. Lavelle mentioned in lecture that test 2 will not include hybridization.
by 504939134
Sun Nov 17, 2019 10:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Shape
Replies: 3
Views: 23

Re: Molecular Shape

When you have 5 regions of electron density your electronic shape is Trigonal bipyramid, such as BrF3, but since in those regions two of those are lone pairs the molecular shape will be T shape. As for NH3, your regions of electronic density is 4 giving it an electronic shape of a tetrahedral, and s...
by 504939134
Sun Nov 17, 2019 10:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E21 part d
Replies: 1
Views: 15

Re: 2E21 part d

In my discussion my TA said that it is sufficient to just write that the bond angles are less than 109.
by 504939134
Sun Nov 10, 2019 6:46 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: Structure and bond type
Replies: 2
Views: 17

Structure and bond type

By just looking at a Lewis structure how can we distinguish the type of bond and dipole moment present?
by 504939134
Sun Nov 10, 2019 6:25 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: Boiling point
Replies: 5
Views: 25

Boiling point

How does a molecules bond type relate to its boiling point? Which types of bonds will cause higher or lower boiling points?
by 504939134
Sun Nov 10, 2019 6:17 pm
Forum: Ionic & Covalent Bonds
Topic: Ionization of Nitrogen vs Oxygen
Replies: 11
Views: 61

Re: Ionization of Nitrogen vs Oxygen

Due to Nitrogen’s half filled orbitals, it makes it more stable and more difficult to remove and electron as opposed to oxygen which has two paired electrons.
by 504939134
Sun Nov 03, 2019 8:19 pm
Forum: Electronegativity
Topic: which bond
Replies: 4
Views: 36

Re: which bond

If the electronegativity difference between the two elements is greater than or equal to 2.5 then it is a ionic bond, if the difference is equal to or below 1.5 it is a covalent bond. Basically the greater the difference in electronegativity the more pull on electrons one element will have over the ...
by 504939134
Sun Nov 03, 2019 8:14 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: isoelectronic definition
Replies: 7
Views: 43

Re: isoelectronic definition

Isoelectric refers to elements that have the same amount of electrons, but have very different chemical characteristics.
by 504939134
Sun Nov 03, 2019 8:09 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: What are the octet exceptions?
Replies: 11
Views: 66

Re: What are the octet exceptions?

Octet exceptions are the first 4 elements in the periodic table which are; H,He,Li, and Be, as they will never have a full octet. An exception to this octet guideline are all elements after Neon, so in the 3p block and on, these elements are allowed to have more than 8 electrons, they don’t have to ...
by 504939134
Sun Nov 03, 2019 8:06 pm
Forum: Lewis Structures
Topic: Which element at center of the structure
Replies: 6
Views: 28

Re: Which element at center of the structure

The element with the lowest ionization energy will always be in the middle, but hydrogen will never be in the middle. Just look at your periodic table and remember that the ionization energy increases as you go across the periodic table (left to right)
by 504939134
Sun Nov 03, 2019 8:04 pm
Forum: Lewis Structures
Topic: Resonance Structure
Replies: 4
Views: 29

Re: Resonance Structure

If asked for a Lewis structure for an element with multiple variations (resonance) you have to include the resonance structures and indicate that there is a hybridization of the the structure, which will be a a combination of the resonance structures. To be safe I would always include it.
by 504939134
Sun Oct 27, 2019 7:41 pm
Forum: Trends in The Periodic Table
Topic: Electron affinity equation
Replies: 1
Views: 16

Electron affinity equation

Can someone explain why in order to find the electron affinity, you need to subtract the energy of the neutral atom from the energy of the final. Thank you.
by 504939134
Sun Oct 27, 2019 7:38 pm
Forum: Ionic & Covalent Bonds
Topic: Writing Electron Configurations for an Ion
Replies: 6
Views: 36

Re: Writing Electron Configurations for an Ion

When writing the electron configuration of an ion, it changes from that of its parent element because you are changing the number of electrons in the element. When writing the change configuration you have to look at the charge of the ion, if its a positive charge it means that electrons were remove...
by 504939134
Sun Oct 27, 2019 7:34 pm
Forum: Lewis Structures
Topic: Clarification
Replies: 6
Views: 53

Re: Clarification

In the lecture Professor Lavelle states that obtaining a formal charge of 0 is much more important than following the octet rule.
by 504939134
Sun Oct 27, 2019 7:32 pm
Forum: Ionic & Covalent Bonds
Topic: Resonance
Replies: 10
Views: 71

Re: Resonance

Resonance just means you can write a Lewis structure in different ways, you can write bonds in different ways, but it is still the same molecule.
by 504939134
Sun Oct 27, 2019 7:30 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Bonds
Replies: 11
Views: 75

Re: Covalent Bonds

Covalent bonds can only be formed by nonmetals, and metals are more likely to form ionic bonds. Remember that metals often times become cations because it is easier for them to give up electrons. Non metals have high ionization energy.
by 504939134
Sun Oct 20, 2019 12:06 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Radiation Type
Replies: 5
Views: 32

Re: Radiation Type

Since there was a question in the homework which asked to name the types of light/radiation from highest to lowest energy, I am assuming we will be tested on it and expected to memorize them, that would be my safest guess.
by 504939134
Sun Oct 20, 2019 12:02 am
Forum: Properties of Light
Topic: Unit for Wavelength
Replies: 34
Views: 160

Re: Unit for Wavelength

It is measured in meters, it is a distance. You can give it in picometers, and nanometers as well.
by 504939134
Sat Oct 19, 2019 11:44 pm
Forum: Photoelectric Effect
Topic: One photon one atom interaction
Replies: 14
Views: 87

Re: One photon one atom interaction

After increasing the frequency and the threshold of the electrons being met, in order to have more electrons being ejected you can then increase the intensity as it produces more photons at this energy, which increases photon, electron interactions. But remember that this will not change the amount ...
by 504939134
Sat Oct 19, 2019 11:41 pm
Forum: Photoelectric Effect
Topic: Intensity of Light
Replies: 5
Views: 37

Re: Intensity of Light

When you increase the intensity of light you are only increasing the number of photons being emitted, this does not increase the energy that each photon emits. In order to have electrons be released from metal, the energy of each individual photon must be high enough to pass the energy threshold and...
by 504939134
Sat Oct 19, 2019 11:39 pm
Forum: Properties of Light
Topic: 1A.9 Energy of Photon
Replies: 12
Views: 79

Re: 1A.9 Energy of Photon

After you find the wavelength of the radiation, you then find the energy by using E=h*v, which is Plancks constant 6.626x10^-34J times frequency which is given. Hope this helps!
by 504939134
Sat Oct 19, 2019 11:35 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Spin up and spin down
Replies: 13
Views: 100

Spin up and spin down

I am having a hard time understanding the concept of different spin states in electrons, I never learned this in High school chem. Can anyone explain how we know if an electron is in a spin up or spin down state?
by 504939134
Sat Oct 19, 2019 11:27 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electron States
Replies: 3
Views: 33

Electron States

What did Professor Lavelle mean when he said that an electron is in a particular state, not in a specific orbital? I am having a hard time understanding this concept.
by 504939134
Sat Oct 12, 2019 10:42 pm
Forum: Properties of Electrons
Topic: Electron Energy Levels
Replies: 8
Views: 47

Re: Electron Energy Levels

From what I recall Professor Lavelle saying is that each atom has unique electronic structures and energy levels, which is why they can only absorb or emit unique frequencies that are allowed by their unique structures.
by 504939134
Sat Oct 12, 2019 10:37 pm
Forum: Photoelectric Effect
Topic: Wave-like Properties
Replies: 4
Views: 46

Re: Wave-like Properties

What I got from lecture was that the larger the mass the smaller the wavelength properties making it not detectable. So anything less that 10^-15m does not have detestable wavelength properties.
by 504939134
Sat Oct 12, 2019 10:35 pm
Forum: Photoelectric Effect
Topic: 1B.7 part b
Replies: 1
Views: 24

Re: 1B.7 part b

For part b you are asked to find the energy emitted by 5 mg of Sodium atoms. You first have to find the number of moles in 5mg of Na, you then take this number and calculate the energy by multiplying the number of moles in 5mg of Na by Avogrado’s constant over 1 mole, you then multiple that by what ...
by 504939134
Sat Oct 12, 2019 10:26 pm
Forum: Photoelectric Effect
Topic: Classic Wave in Photoelectric effect
Replies: 5
Views: 44

Classic Wave in Photoelectric effect

Why does does the the model equation Ek=1/2Me-ve^2 not change when you increase intensity? How is this different from the wave model?
by 504939134
Sat Oct 12, 2019 9:58 pm
Forum: Photoelectric Effect
Topic: Removing electrons in Photoelectric concept
Replies: 2
Views: 16

Removing electrons in Photoelectric concept

In lecture we went over the photoelectric effect, and I understood that if an incoming photon does not have the energy needed to remove an electron, and electron won’t be ejected. My question is what is that threshold that the photon should hit? What energy level are we comparing it to and why?
by 504939134
Wed Oct 02, 2019 11:20 pm
Forum: Empirical & Molecular Formulas
Topic: Clarification on the Vitamin C Example
Replies: 6
Views: 72

Re: Clarification on the Vitamin C Example

I believe this was because we are supposed to round up.
by 504939134
Wed Oct 02, 2019 11:18 pm
Forum: Empirical & Molecular Formulas
Topic: HW 1 Problem F.9
Replies: 7
Views: 145

Re: HW 1 Problem F.9

Yes, the empirical formula is the ratio of elements, unlike the molecular formula which gives you the exact numbers of elements in a compound.
by 504939134
Wed Oct 02, 2019 11:17 pm
Forum: Empirical & Molecular Formulas
Topic: QUESTION F.21 HW
Replies: 3
Views: 34

Re: QUESTION F.21 HW

You would first find the number of moles of each element. For example for the moles of Carbon you would divide the mass of the element in the compound which is 1.11mg (remember to convert this to grams) to the molar mass of carbon which is 12.01 g. Mol^-1. You would then find the moles of the rest o...
by 504939134
Wed Oct 02, 2019 11:11 pm
Forum: Empirical & Molecular Formulas
Topic: Question F.13 [ENDORSED]
Replies: 4
Views: 43

Question F.13 [ENDORSED]

In this question is 4.14g also its percent composition? Would you assume that 4.14g translates to 4.14%?
by 504939134
Wed Oct 02, 2019 11:09 pm
Forum: Empirical & Molecular Formulas
Topic: Fundamental F question 7
Replies: 3
Views: 44

Fundamental F question 7

I’m having trouble finding the molar mass of the unknown metal, I set the mass of the compound to 100g but I do not know how I’d get to the molar mass of the metal. How would you get to the molar mass with only the mass percentage of it?

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