## Search found 61 matches

Wed Jan 20, 2021 9:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW Question
Replies: 3
Views: 20

### HW Question

If the Ka of a monoprotic weak acid is 8.6×10−6, what is the pH of a 0.33 M solution of this acid?

How would I do this problem?
Sun Jan 17, 2021 10:20 pm
Forum: Ideal Gases
Topic: Kp?
Replies: 20
Views: 41

### Re: Kp?

Yes, partial pressure only applies to gases.
Sun Jan 17, 2021 10:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Week 1 #6
Replies: 10
Views: 30

### Re: Sapling Week 1 #6

You find Q by using the equation Q=products/reactants. Make sure you remember that the numbers in front get used as exponents, and products go on top.
Sun Jan 17, 2021 10:16 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Total Pressure
Replies: 20
Views: 43

### Re: Total Pressure

Total pressure is all pressures combined at equilibrium. It is found by adding up the partial pressures of all the compounds in a reaction.
Sun Jan 17, 2021 10:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Week 1 #9
Replies: 3
Views: 33

### Re: Sapling Week 1 #9

Im honestly struggling to see any faults in your work. Was your final answer 0.825 M? If it was I do not know, maybe contact your TA to help.
Fri Jan 15, 2021 8:46 pm
Forum: Ideal Gases
Topic: Hw Question #4
Replies: 5
Views: 50

### Hw Question #4

At a certain temperature, the given reaction has an equilibrium constant of Kp=369 .

PCl3(g)+Cl2(g)↽−−⇀PCl5(g)

PCl5 is placed in a sealed container at an initial pressure of 0.0800 bar . What is the total pressure at equilibrium?

How would I go about doing this?
Sun Jan 10, 2021 1:16 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H2O
Replies: 44
Views: 280

### Re: H2O

The only time that this is included in the table is when it is in gas (g) form. The compound is not included if it is in liquid or solid phases.
Sun Jan 10, 2021 1:13 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Picking Value when doing Quadratic Equation
Replies: 10
Views: 29

### Re: Picking Value when doing Quadratic Equation

Based on the results you get, one should be the obvious answer. For example, if your two answers are 2 and -2, the answer is 2 as you use the positive number. Additionally, if that number is larger than the original concentration, then it won't be the answer. You can't have more of a change than the...
Sun Jan 10, 2021 1:07 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW Question
Replies: 2
Views: 20

### HW Question

At a certain temperature, 0.820 mol SO3 is placed in a 4.50 L container.

2SO3(g)↽−−⇀2SO2(g)+O2(g)

At equilibrium, 0.170 mol O2 is present. Calculate Kc.

For this would you just have to find the molarity of each compound and then plug it into the equation for Kc?
Sun Jan 10, 2021 1:05 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: HW Question
Replies: 8
Views: 41

### HW Question

Consider the reaction of NH3 and I2 to give N2 and HI. 2NH3(g)+3I2(g)↽−−⇀N2(g)+6HI(g)K Using two or more of the given equations, determine the equilibrium constant, K , for the reaction of NH3 with I2. H2(g)+I2(g)↽−−⇀2HI(g)I2(g)↽−−⇀2I(g)N2(g)+3H2(g)↽−−⇀2NH3(g)H2(g)+Cl2(g)↽−−⇀2HCl(g)Ka=160Kb=2.1×10−3...
Sun Jan 10, 2021 1:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units
Replies: 27
Views: 85

### Re: Units

I believe for pressure bars are what we use (they are very similar to atm).
Tue Dec 15, 2020 3:22 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: What are the bond angles for T shaped?
Replies: 17
Views: 116

### Re: What are the bond angles for T shaped?

Slightly less than 90 degrees as the electron pairs have repulsion.
Tue Dec 15, 2020 3:04 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem community points
Replies: 16
Views: 118

### Re: Chem community points

The new due date is thursday, so it wont be updated until then!
Tue Dec 15, 2020 3:01 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Square Planar vs. Tetrahedral
Replies: 15
Views: 123

### Re: Square Planar vs. Tetrahedral

Tetrahedral has 4 bonds to atoms, and no lone pairs (AX4). Square planar has 4 bonds to atoms, and 2 lone pairs(AX4E2).
Tue Dec 15, 2020 2:59 pm
Forum: Student Social/Study Group
Topic: Curve
Replies: 29
Views: 204

### Re: Curve

There is no curve, but he did say that he is adding 10 points to the final grade. That should help!
Tue Dec 15, 2020 2:58 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Ground State of H
Replies: 3
Views: 38

### Re: Ground State of H

yes! that is what that means!
Sun Dec 06, 2020 9:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: HW Question coordination number
Replies: 4
Views: 25

### HW Question coordination number

After guessing a few times I got that the coordination number for [Co(SO4)(NH3)5]+ is 6.
Does anyone know why this is?
Sun Dec 06, 2020 9:08 pm
Forum: Properties of Light
Topic: Photoelectric Effect
Replies: 14
Views: 138

### Re: Photoelectric Effect

Yes it is. The energy of the photon-the threshold energy is = to the kinetic energy.
Sun Dec 06, 2020 9:03 pm
Forum: Properties of Light
Topic: Is c always the speed of light?
Replies: 88
Views: 457

### Re: Is c always the speed of light?

In this case, this will only be the speed of light. It may change in future classes (I'm not sure), but for now this is the speed of light. The constant is around 3 x 10^8
Sun Dec 06, 2020 8:56 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: How to find coordination number.
Replies: 10
Views: 33

### Re: How to find coordination number.

To find the coordination number, you need to look at how many ligands are connected to the central atom. For example, in the compound [CuCl2]-, the coordination number is 2. There are 2 Cl atoms around the Cu atom. Another example would be Ba[FeBr4]2. Since you only count whats on the inside of the ...
Sat Dec 05, 2020 9:42 pm
Forum: Naming
Topic: en
Replies: 8
Views: 76

### en

When naming compounds, what does en mean?
Sat Dec 05, 2020 9:40 pm
Forum: Lewis Acids & Bases
Topic: Application to the Period Table
Replies: 6
Views: 49

### Re: Application to the Period Table

From the lectures, we learn that the left side (alkali metals) usually give rise to base oxidation. On the right side you generally see acid oxides being formed from the halogens, etc. In the middle, near the transition metals and metalloids you will see amphoteric atoms. Hope this helps!
Sat Dec 05, 2020 9:34 pm
Forum: Dipole Moments
Topic: Polarity from Shape
Replies: 12
Views: 108

### Re: Polarity from Shape

Bent molecules are asymmetrical, generally leading to a polar molecule. For example, since water is bent and the two H atoms are electronegative towards the O atom, it does not cancel out. This is why water is polar, and most bent molecules follow that trend.
Sat Dec 05, 2020 9:23 pm
Forum: Lewis Acids & Bases
Topic: Bronsted vs. Lewis bases
Replies: 11
Views: 72

### Re: Bronsted vs. Lewis bases

They are similar, but have some differences. A Lewis base is a base in which an electron is donated to another atom. A Bronsted base is one who accepts a proton (from an H), making that atom basic. They talk about different reactions but lead to the same concept.
Sat Dec 05, 2020 8:59 pm
Forum: Naming
Topic: HW Question #1
Replies: 7
Views: 93

### HW Question #1

Does anyone know how to answer this? My questions asks what the name of this compound is. Thank you!

[Co(NH3)4Cl2]Cl
Sat Dec 05, 2020 8:56 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Numbers
Replies: 8
Views: 55

### Re: Coordination Numbers

Hi! Coordination number refers to the number of ligand atoms bonding to the central transition metal. For example, if the compound is ZnCl4 there are 4 chlorine atoms bound to the central atom, Zinc. If you have brackets (e.g K4[Fe(Cn)6]-) you would only count the atoms on the inside. So in this cas...
Sun Nov 22, 2020 12:44 pm
Forum: Hybridization
Topic: HW Question
Replies: 3
Views: 49

### HW Question

What is the hybridization of phosphorus in each of the molecules or ions?
The first molecule shown is PCl3
thank you!
Sun Nov 22, 2020 12:41 pm
Forum: Lewis Structures
Topic: Central Atom Question
Replies: 20
Views: 135

### Re: Central Atom Question

H will never be the central atom because it is only allowed to form 1 bond to fill its octet.
Sun Nov 22, 2020 12:40 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Expanded Octets
Replies: 9
Views: 85

### Re: Expanded Octets

Usually, atoms after the 3p subshell can have an expanded octet, but I'm not sure what the rule is for atoms in the 6p subshell.
Sun Nov 22, 2020 12:38 pm
Forum: Trends in The Periodic Table
Topic: Ionic Character
Replies: 11
Views: 92

### Ionic Character

How do you determine ionic/covalent character again?
There was a question on the midterm that I was stuck on.
Sun Nov 22, 2020 12:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling #4
Replies: 5
Views: 47

### Sapling #4

How many outer atoms and lone pairs are present in a molecule with a see‑saw shape?

Do you guys know?
Sun Nov 15, 2020 9:33 pm
Forum: Ionic & Covalent Bonds
Topic: midterm 2: knowing compounds
Replies: 14
Views: 76

### Re: midterm 2: knowing compounds

Because we haven't been taught nomenclature of names of compounds yet they will be provided in this midterm.
Sun Nov 15, 2020 9:29 pm
Forum: Ionic & Covalent Bonds
Topic: Homework due date
Replies: 49
Views: 336

### Re: Homework due date

Sunday at 11:59 pm, not Sunday at 12:00 am.
Sun Nov 15, 2020 9:28 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation Sapling 9
Replies: 6
Views: 80

### Oxidation Sapling 9

Using number 9 in the sapling hw as an example, how do you find the oxidation number? And how do you know which structure is applies to? Thank you!
Sun Nov 15, 2020 9:26 pm
Forum: General Science Questions
Topic: Midterm 2
Replies: 12
Views: 91

### Re: Midterm 2

The last 8 on outline 2 and all of outline 3!
Sun Nov 15, 2020 6:06 pm
Forum: Bond Lengths & Energies
Topic: Hydrogen Bonding
Replies: 13
Views: 68

### Re: Hydrogen Bonding

Hi! There are no exceptions, only happens when F, O, N, H are present.
Sun Nov 08, 2020 11:29 pm
Forum: SI Units, Unit Conversions
Topic: conversion factors
Replies: 8
Views: 62

### Re: conversion factors

Nope, any ones that aren't given on the constants and equations sheet will be given in the problem!
Sun Nov 08, 2020 11:27 pm
Forum: Student Social/Study Group
Topic: Mid-quarter Check in
Replies: 67
Views: 281

### Re: Mid-quarter Check in

I hate online school, I wish we were on campus!
Sun Nov 08, 2020 11:23 pm
Forum: Ionic & Covalent Bonds
Topic: HW Question
Replies: 4
Views: 54

### HW Question

Select which intermolecular forces of attraction are present between CH3CHO molecules.

does anyone know what they are?
Sun Nov 08, 2020 11:21 pm
Forum: Ionic & Covalent Bonds
Topic: HW Question
Replies: 2
Views: 21

### HW Question

Urea is an organic compound widely used as a fertilizer. Its solubility in water allows it to be made into aqueous fertilizer solutions and applied to crops in a spray. What is the maximum theoretical number of water molecules that one urea molecule can hydrogen bond with? Ignore shape for the purpo...
Sun Nov 08, 2020 11:16 pm
Forum: Student Social/Study Group
Topic: Veterans Day
Replies: 16
Views: 134

### Re: Veterans Day

My other classes are having us change to another day, so i'm guessing it is either cancelled or postponed.
Sun Nov 01, 2020 6:39 pm
Forum: Student Social/Study Group
Topic: Sappling #27
Replies: 3
Views: 47

### Re: Sappling #27

No it is not relevant, just plug in the uncertainty in velocity to find the uncertainty in position.
Sun Nov 01, 2020 6:13 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Question 26 Sapling
Replies: 5
Views: 61

### Question 26 Sapling

On the Sapling HW, it asks

What is the minimum uncertainty in an electron's velocity (Δvmin) if the position is known within 13 Å.

How do I solve this?
Sun Nov 01, 2020 6:12 pm
Forum: DeBroglie Equation
Topic: energy of a photon
Replies: 3
Views: 32

### energy of a photon

The E Coli bacterium is about 2.4 μm long. Suppose you want to study it using photons of that wavelength or electrons having that de Broglie wavelength.

What is the energy E photon of the photon?

How do I solve this?
Sat Oct 31, 2020 4:43 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: N levels for electron configurations
Replies: 6
Views: 45

### Re: N levels for electron configurations

The l # represents the subshell. In this case, when l=1 it represents the p subshell. As we know, there can be a total of 6 electrons. To take it even further, they could ask using the ml value as well. For the p subshell, there are three possible orbitals: -1, 0, and 1. We know that each orbital ca...
Sat Oct 31, 2020 4:30 pm
Forum: Trends in The Periodic Table
Topic: Electron Affinity
Replies: 2
Views: 39

### Electron Affinity

Here is my question on number 23. The electron affinity of thulium has been measured by a technique known as laser photodetachment electron spectroscopy. In this technique, a gaseous beam of the anions of an element is bombarded with photons from a laser. Electrons from the anion are then ejected an...
Wed Oct 28, 2020 9:27 pm
Forum: DeBroglie Equation
Topic: Conversions
Replies: 9
Views: 94

### Conversions

Im studying for the midterm and going over questions from the book. There is one asking you to find the wavelength of a baseball traveling 92 mph, and I know how to solve it. However, I know that you need a number to convert miles to kilometers, will we need to memorize this and other conversions fo...
Sat Oct 24, 2020 2:07 pm
Forum: Einstein Equation
Topic: Usage of E=hv
Replies: 10
Views: 101

### Re: Usage of E=hv

Yes this is used for photons as there is no mass, but when there is mass (an electron has a constant mass listed on the constants sheet) then you use DeBroglie's equation to solve for wavelength. Hope this helped!
Sat Oct 24, 2020 2:02 pm
Forum: Student Social/Study Group
Topic: Midterm Prep
Replies: 15
Views: 99

### Re: Midterm Prep

My TA said that it would be around 10 questions, with no more than 4 long multiple step problems. To study I recommend doing the book questions and going over lectures.
Sat Oct 24, 2020 1:57 pm
Forum: Properties of Light
Topic: Constants
Replies: 21
Views: 106

### Re: Constants

I would use how ever many are shown on the sheet of equations and constants that we print out, but the more that you use the closer your answer will be to the correct answer.
Mon Oct 19, 2020 3:41 pm
Forum: DeBroglie Equation
Topic: Question about 10/19/2020 lecture regarding DeBrogile Equation example
Replies: 4
Views: 38

### Re: Question about 10/19/2020 lecture regarding DeBrogile Equation example

That number is the universal mass of an electron. I'm guessing we don't have to memorize it, if it's on the midterm i'm sure it will be provided.
Sun Oct 18, 2020 2:40 pm
Forum: Photoelectric Effect
Topic: Practice Quiz Question
Replies: 3
Views: 20

### Practice Quiz Question

In my practice quiz, the question had the unit keV. What is that?
Sun Oct 18, 2020 2:36 pm
Forum: Einstein Equation
Topic: m vs nm
Replies: 66
Views: 438

### Re: m vs nm

If the question asks, then I assume that you would need to convert to nm. However, if it doesn't mention anything Lavelle said that meters will work in the solution.
Sun Oct 18, 2020 2:29 pm
Forum: Student Social/Study Group
Topic: studying for exams
Replies: 21
Views: 251

### Re: studying for exams

I think going over the textbook problems is the best overall way to study as these will be like the questions on the midterm. When it comes closer to the exam I would go over notes, and even though you don't need to memorize equations I would make sure you know when and how to use each one.
Sun Oct 18, 2020 2:25 pm
Forum: Limiting Reactant Calculations
Topic: Difference between limiting reactant and limiting reagent?
Replies: 14
Views: 109

### Re: Difference between limiting reactant and limiting reagent?

These terms mean the same thing and are used interchangeably in a question. You calculate them both the same way!
Sun Oct 18, 2020 2:23 pm
Forum: Photoelectric Effect
Topic: photoelectric effect
Replies: 17
Views: 127

### Re: photoelectric effect

Yes, they are the same thing. They both are the amount of energy required from a wave of light to remove an electron from a metal.
Fri Oct 09, 2020 2:28 pm
Forum: Balancing Chemical Reactions
Topic: State of matter in reaction
Replies: 9
Views: 37

### Re: State of matter in reaction

The state of matter doesn't affect how you should balance the equation (law of conservation of mass), but it should be written out when writing the equation down.
Fri Oct 09, 2020 2:21 pm
Forum: SI Units, Unit Conversions
Topic: Angstroms
Replies: 7
Views: 64

### Re: Angstroms

Im guessing that it would just be a capital A, but if not then you could probably write it out (10^-10 m).
Thu Oct 08, 2020 5:16 pm
Forum: Administrative Questions and Class Announcements
Replies: 12
Views: 126

In order to get these points (maximum 5 points per week), you must post on the chemistry community page, this could be either asking questions or answering other people's questions.
Thu Oct 08, 2020 5:13 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Textbook question E.1
Replies: 7
Views: 86

### Re: Textbook question E.1

HI! So first I would change the radius to diameter, so multiply the 144 by 2. Next you need to find how many atoms come in one mole of Ag, and to do that you would multiply 1 mole by 6.02x10^23 (avagadro's constant). When you find out how many atoms, multiply that by 288 pm (the length each atom tak...
Thu Oct 08, 2020 5:06 pm
Forum: SI Units, Unit Conversions
Topic: Sig figs and molar mass
Replies: 18
Views: 101

### Re: Sig figs and molar mass

What I do is I use the periodic table given by Sapling, and use the correct amount of significant figures given by the problem(always use the least amount of sig figs presented by a piece of the equation). We all use the same periodic table during tests, but generally I would use Sapling as the peri...