Search found 66 matches

by kristinalaudis3e
Sun Jan 24, 2021 11:39 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: isolated system
Replies: 9
Views: 231

Re: isolated system

yes because isolated systems cant exchange energy or matter!
by kristinalaudis3e
Sun Jan 24, 2021 11:34 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: intensive vs extensive
Replies: 8
Views: 209

Re: intensive vs extensive

extensive depends on the amount of a substance (ex: mass) while intensive doesn't depend on the amount of a substance (ex: density).
it is important to know so that you can use the right constants in your equation
by kristinalaudis3e
Sun Jan 24, 2021 11:31 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Differences
Replies: 6
Views: 210

Re: Differences

isolated systems can't exchange energy or matter so no outside sources can affect the reaction, open systems can exchange both energy and matter so a lot of outside factors can affect the reaction, and closed systems can only exchange energy so few outside sources such as temperature can affect the ...
by kristinalaudis3e
Sun Jan 24, 2021 11:28 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Open Systems
Replies: 12
Views: 205

Re: Open Systems

since open systems allow for the exchange of matter and energy, I think that any thermodynamic equation can be used so long as you pay attention to if it has constant pressure and volume
by kristinalaudis3e
Sun Jan 24, 2021 11:26 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: closed system
Replies: 8
Views: 146

Re: closed system

Closed systems have a fixed amount of matter and don't allow for the exchange of matter. A clear example would be like the water bottle example mentioned above. A closed water bottle doesn't allow the water inside to leak!
by kristinalaudis3e
Sun Jan 17, 2021 11:42 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units to know
Replies: 11
Views: 24

Re: Units to know

I think for pressure, you need to know atm and torr!
by kristinalaudis3e
Sun Jan 17, 2021 11:38 pm
Forum: Ideal Gases
Topic: Kc vs. Kp
Replies: 14
Views: 41

Re: Kc vs. Kp

Kc and Kp are calculated in the same way and both can be used for gases, but the only difference is that one is for partial pressures and one is for concentration. for whichever version you choose, make sure youre consistent with it the whole way through!
by kristinalaudis3e
Sun Jan 17, 2021 11:36 pm
Forum: Ideal Gases
Topic: Gas for equilibrium equation
Replies: 8
Views: 31

Re: Gas for equilibrium equation

P is used to note that it is partial pressure being used instead of concentration! but both Kc and Kp can be used for gases
by kristinalaudis3e
Sun Jan 17, 2021 11:34 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling Week 1 #5
Replies: 8
Views: 45

Re: Sapling Week 1 #5

yes just multiply them!!
by kristinalaudis3e
Sun Jan 17, 2021 11:33 pm
Forum: Ideal Gases
Topic: Inverse Kc
Replies: 34
Views: 85

Re: Inverse Kc

if it goes fro A+B--> C then it would be K but if it goes from C-->A+B then it would be 1/K
by kristinalaudis3e
Sun Jan 17, 2021 11:29 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Box
Replies: 10
Views: 35

Re: ICE Box

if it gives you the initial value, then the change is -(stoich coefficient)x but if there is no initial concentration, then the change is +(stoich coefficient)x
by kristinalaudis3e
Sun Jan 10, 2021 10:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: change in K
Replies: 22
Views: 66

Re: change in K

because K is a constant, the only thing that changes K is temperature :)
by kristinalaudis3e
Sun Jan 10, 2021 10:20 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Sapling #2
Replies: 3
Views: 35

Re: Sapling #2

definitely use the ICE table as the other responses said, but also don't forget to divide the moles by liters in order to get molarity!
by kristinalaudis3e
Sun Jan 10, 2021 10:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5G.1
Replies: 4
Views: 12

Re: 5G.1

yes Q would change!!
by kristinalaudis3e
Sun Jan 10, 2021 10:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Concentration vs Pressure
Replies: 9
Views: 41

Re: Concentration vs Pressure

when calculating, yes they are the same mathematically, but conceptually they are different. concentration is solely based on moles whereas partial pressures are related to temperatures and moles
by kristinalaudis3e
Sun Jan 10, 2021 10:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Stoichiometric Coefficients
Replies: 5
Views: 22

Re: Stoichiometric Coefficients

I don't think Lavelle explained it either, but as long as you remember that they become exponents when calculating K and Q, then I think you should be fine :)
by kristinalaudis3e
Tue Dec 15, 2020 8:10 pm
Forum: Hybridization
Topic: Double Pi Bonds
Replies: 6
Views: 61

Re: Double Pi Bonds

So in a triple bond, one is a sigma bond and 2 are pi bonds. For the sigma bonds, they will overlap end to end, but for the pi bonds, they have to overlap side by side. The 2 pi bonds are formed when the unoccupied p orbitals that are not overlapping end to end then overlap side by side with the oth...
by kristinalaudis3e
Tue Dec 15, 2020 8:04 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Oxidation #s help
Replies: 5
Views: 31

Oxidation #s help

How oxidation numbers, I know that you would usually look at the number of ligands attached to the central Atom and based off their charges calculate the oxidation number of the whole molecule, but if there is an atom attached to the outside (so not the central atom), can you use only that atom to c...
by kristinalaudis3e
Tue Dec 15, 2020 8:02 pm
Forum: Lewis Acids & Bases
Topic: Lewis acids and bases vs Bronsted Acids and Bases
Replies: 4
Views: 37

Lewis acids and bases vs Bronsted Acids and Bases

What exactly is the difference between these two? or can I assume that a Lewis acid is a bronsted base and a Lewis base is a bronsted acid.
by kristinalaudis3e
Tue Dec 15, 2020 7:59 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Bond Angles
Replies: 8
Views: 74

Bond Angles

For a lewis structure with 3 bonds and one lone pair have a bond angle closer to 106 (from lecture) or will it have a bond angle that is just less than that of a tetrahedral (109.5)?
by kristinalaudis3e
Tue Dec 15, 2020 7:57 pm
Forum: Bronsted Acids & Bases
Topic: Acids in solution
Replies: 3
Views: 22

Acids in solution

Hello,

In lecture Lavelle stated that acid in a solution will be at pH 6. Does he mean the acid itself is at pH 6 or does he mean the solution will become pH 6?
by kristinalaudis3e
Sun Dec 06, 2020 11:28 pm
Forum: Dipole Moments
Topic: London Dispersion Forces
Replies: 8
Views: 70

Re: London Dispersion Forces

London dispersion forces happen in all molecules because electrons are constantly moving around the nucleus and when electrons randomly become closer to each other, they create temporary dipoles which is a form of attraction.
by kristinalaudis3e
Sun Dec 06, 2020 11:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: sigma vs pi bonds
Replies: 33
Views: 185

Re: sigma vs pi bonds

Sigma bonds are in all bonds while pi bonds are only in double and triple bonds. In a single bond there is only one sigma bond. In a double bond, there is one sigma and one pi bond and in a triple bond there is one sigma and 2 pi bonds.
by kristinalaudis3e
Sun Dec 06, 2020 11:23 pm
Forum: Biological Examples
Topic: Hemoglobin
Replies: 12
Views: 226

Re: Hemoglobin

Hemoglobins transports oxygen through the blood and myoglobins store oxygen in the muscles
by kristinalaudis3e
Sun Dec 06, 2020 11:21 pm
Forum: Lewis Acids & Bases
Topic: Water
Replies: 62
Views: 492

Re: Water

it can act as both!
by kristinalaudis3e
Sun Dec 06, 2020 11:20 pm
Forum: Identifying Acidic & Basic Salts
Topic: Concept of pH
Replies: 10
Views: 51

Re: Concept of pH

high H+ count is acidic and low H+ count is basic
by kristinalaudis3e
Fri Nov 27, 2020 12:54 pm
Forum: Hybridization
Topic: Sapling #12
Replies: 27
Views: 190

Re: Sapling #12

The hybridization of atoms depends on the number of regions of electron density. both C and O have 4 regions, therefore it has a sp3 hybridization.
by kristinalaudis3e
Fri Nov 27, 2020 12:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling 17
Replies: 8
Views: 79

Re: Sapling 17

I made 2 linear structures as well with the first containing double bonds between all 3 carbons and the carbons at the ends each have 2 hydrogens attached with a single bond. The next linear structure had the 3 carbons connected by a single and a triple bond. The single bonded carbon at the end has ...
by kristinalaudis3e
Fri Nov 27, 2020 12:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Sapling 16
Replies: 6
Views: 54

Re: Sapling 16

having a delocalized pi bond means that the pi bond doesn't have one set place and had the option to be placed elsewhere within the molecule. You know that there are delocalized pi bonds usually when there are resonance structures.
by kristinalaudis3e
Fri Nov 27, 2020 12:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: sigma bonds and single bonds
Replies: 5
Views: 29

Re: sigma bonds and single bonds

sigma bonds occur in single, double, and triple bonds. I like to think of it kinda like how London forces are present in all bonds. The only additional info you need to know is that double and triple bonds also contain pi bonds, with double bonds having one pi bond and triple bonds having two.
by kristinalaudis3e
Fri Nov 27, 2020 12:37 pm
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: ionic liquids
Replies: 7
Views: 102

Re: ionic liquids

it is a salt in a liquid state and has a really low melting point
by kristinalaudis3e
Fri Nov 27, 2020 12:35 pm
Forum: *Liquid Structure (Viscosity, Surface Tension, Liquid Crystals, Ionic Liquids)
Topic: Liquid crystals
Replies: 2
Views: 34

Re: Liquid crystals

A liquid crystal has properties between those of typical liquids and solids. They are able to flow like a liquid but will be arranged in a way similar to crystals.
by kristinalaudis3e
Mon Nov 23, 2020 12:01 am
Forum: Coordinate Covalent Bonds
Topic: How?
Replies: 3
Views: 80

How?

How do I know if it will actually bond to make a coordinate covalent bond? I understand that one accepts the pair and one donates the pair, but how do you know if it will willingly donate?
by kristinalaudis3e
Mon Nov 23, 2020 12:00 am
Forum: Octet Exceptions
Topic: Expanded octets
Replies: 2
Views: 36

Expanded octets

How do I know how big expanded octets can expand?
by kristinalaudis3e
Sun Nov 22, 2020 11:59 pm
Forum: Bond Lengths & Energies
Topic: Higher Melting Point
Replies: 27
Views: 218

Re: Higher Melting Point

CHI3 has a higher melting point because it has stronger bonds. Because of its size, it has more polarizability.
by kristinalaudis3e
Sun Nov 22, 2020 11:58 pm
Forum: Dipole Moments
Topic: Dipole Moments [ENDORSED]
Replies: 3
Views: 62

Dipole Moments [ENDORSED]

Can someone please explain what a dipole moment is? I know that dipoles have partial charges but what is a dipole moment?
by kristinalaudis3e
Sun Nov 22, 2020 11:57 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 4
Views: 53

Resonance Structures

How do I know the true length of bonds when there are resonance structures? Specifically, how do I know which ones contribute the most?
by kristinalaudis3e
Sun Nov 15, 2020 7:56 am
Forum: Bond Lengths & Energies
Topic: Covalent Bond Length
Replies: 13
Views: 133

Re: Covalent Bond Length

the higher the electronegativity of the atom, the stronger the pull on electrons meaning that the bond length would be shorter and stronger. same goes for atomic radius. if the atoms have a small radius, the electrons are more tightly held, meaning the bonds would be stronger and shorter. triple bon...
by kristinalaudis3e
Sun Nov 15, 2020 7:51 am
Forum: Lewis Structures
Topic: how to draw lewis structures w double bonds
Replies: 3
Views: 37

how to draw lewis structures w double bonds

how do you know if you need to make the central atom have a double bond with the other atoms or if you can just leave them as lone pair electrons on the central atom?
by kristinalaudis3e
Sun Nov 15, 2020 7:49 am
Forum: Resonance Structures
Topic: Determining oxidation numbers?
Replies: 9
Views: 42

Re: Determining oxidation numbers?

the oxidation numbers of all the atoms should equal the charge on the whole compound. on the sapling question, we know that oxygen has an oxidation number of -2, so if there are four oxygens (-2x4=-8) and the whole compound needs to equal -1, then the oxidation number of chlorine should be +7
by kristinalaudis3e
Sun Nov 15, 2020 7:40 am
Forum: Lewis Structures
Topic: Lewis structure based on oxidation #
Replies: 2
Views: 39

Re: Lewis structure based on oxidation #

on the hint given by sapling, it states that the sum of the oxidation numbers is equal to the formal charge of the molecule. knowing that there was a formal charge of -1 on the whole molecule and that the four oxygens each had a oxidation number of -2 (totaling to -8), you can deduce the chlorine at...
by kristinalaudis3e
Sun Nov 15, 2020 7:38 am
Forum: Electronegativity
Topic: hydrogen bonds w/ carbon
Replies: 5
Views: 34

hydrogen bonds w/ carbon

why can't H make a hydrogen bond with carbon? I understand that hydrogen bonds can be made with N, O, and F because they're extremely electronegative and so they pull electrons towards them (making it partially negative), but then the difference in electronegativity of carbon and hydrogen is not sig...
by kristinalaudis3e
Sun Nov 08, 2020 11:59 pm
Forum: Lewis Structures
Topic: Lewis Structure Drawing
Replies: 2
Views: 10

Lewis Structure Drawing

Hi what is the general guideline for drawing lewis structures? Thanks!
by kristinalaudis3e
Sun Nov 08, 2020 11:58 pm
Forum: Octet Exceptions
Topic: octet rule exceptions
Replies: 6
Views: 44

Re: octet rule exceptions

1. odd number of electrons in molecules, ex: NO
2. when 1+ atoms in a molecule have 8+ electrons, ex: SF6
3. when 1+ atoms in a molecule have >8 electrons, ex: BCl3
by kristinalaudis3e
Sun Nov 08, 2020 11:55 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy/Effective Nuclear Charge
Replies: 3
Views: 24

Re: Ionization Energy/Effective Nuclear Charge

I think they're relieved because the oxygen atom needs one electron in the p levels to be stable and when its ionized, the electrons are spinning in opposing ways.
by kristinalaudis3e
Sun Nov 08, 2020 11:52 pm
Forum: Ionic & Covalent Bonds
Topic: HW Question
Replies: 2
Views: 21

Re: HW Question

Start by drawing the lewis structure of the compound and you'll notice that hydrogen bonds can occur for NOF atoms because they'll bond to the lone pairs. This means that there will be 8.
by kristinalaudis3e
Sun Nov 01, 2020 5:35 am
Forum: Properties of Light
Topic: 1A.3 Question
Replies: 3
Views: 52

Re: 1A.3 Question

The answer is C because using the equation c=wavelength*v we know that c is a constant. Therefore if there are bigger wavelengths, then the frequency must decrease and if there are smaller wavelengths, then frequency must increase (they are inversely related). The change in the electrical field refe...
by kristinalaudis3e
Sun Nov 01, 2020 5:23 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Sapling HW Q17
Replies: 18
Views: 141

Re: Sapling HW Q17

An easy way to remember atomic radius size trends on the periodic table is that it increases going to the left and it increases going down. The explanation above does a good job of explaining why, but this is just a little too for memorization purposes :)
by kristinalaudis3e
Sun Nov 01, 2020 5:17 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Sapling HW Q21
Replies: 4
Views: 41

Re: Sapling HW Q21

The trend for electron affinity on the periodic table is that it increases from left to right and it decreases from top to bottom. Those with high electron affinity are also more likely to release energy when placing an electron while those with low electron affinity will absorb energy. Therefore, B...
by kristinalaudis3e
Sun Nov 01, 2020 5:11 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Affinity
Replies: 4
Views: 27

Re: Electron Affinity

When an electron has a high electron affinity, it will release a lot of energy when it gains an electron while one w a low electron affinity will release very little energy and absorb it.
by kristinalaudis3e
Sun Nov 01, 2020 5:00 am
Forum: Trends in The Periodic Table
Topic: Question about Ionization energy
Replies: 4
Views: 34

Re: Question about Ionization energy

Hello, Ionization energy is the energy needed to remove an electron, so I guess it could just describe the concept as a whole, whereas the first ionization energy is the energy needed to remove an electron from a neutral atom while the second ionization is the energy needed to remove an electron fro...
by kristinalaudis3e
Sun Oct 25, 2020 11:42 pm
Forum: Quantum Numbers and The H-Atom
Topic: Energy Level Excited
Replies: 8
Views: 69

Re: Energy Level Excited

An excited electron is one that gains energy through photons and this makes it move to an energy level higher than the ground state. I like to think of the ground state as the base level that electrons are already on. So when it moves from a higher energy level back to its ground state, it is releas...
by kristinalaudis3e
Sun Oct 25, 2020 11:38 pm
Forum: Properties of Electrons
Topic: Geiger and Marsden Experiment
Replies: 2
Views: 27

Re: Geiger and Marsden Experiment

They were able to discover that atoms had a concentrated mass within the nucleus (including all the positive charges) through their foil experiment because of how the the alpha particle beamed scattered after hitting foil. They found that most of the particles could go through and only a tiny fracti...
by kristinalaudis3e
Sun Oct 25, 2020 11:18 pm
Forum: Ionic & Covalent Bonds
Topic: Strength of bonds
Replies: 13
Views: 90

Re: Strength of bonds

Covalent bonds are the strongest bonds, hydrogen bonds are the weakest, and ionic bonds are moderately strong. I hope this helps :)
by kristinalaudis3e
Sun Oct 25, 2020 11:04 pm
Forum: Photoelectric Effect
Topic: Photons vs electrons
Replies: 2
Views: 23

Re: Photons vs electrons

I agree with the statement above. In the photoelectric effect, we want the energy in the photon to be enough to eject one electron. Therefore, they would have to be a 1:1 ratio. Hopefully, this is helpful!
by kristinalaudis3e
Sun Oct 25, 2020 11:00 pm
Forum: Properties of Light
Topic: 1A.9 problem
Replies: 7
Views: 76

Re: 1A.9 problem

To convert 300 MHz to Hz you would multiply it by 10^6. This is because Hz refers to the frequency, in which one cycle goes every second. MHz or Megahertz indicates millions, which is 1 x 10^6. I hope this helps!
by kristinalaudis3e
Sun Oct 18, 2020 11:36 pm
Forum: Limiting Reactant Calculations
Topic: General Limiting Question
Replies: 9
Views: 68

Re: General Limiting Question

For the most part, the limiting reactant determines how much products can be produced with the full consumption of that reactant, so technically yes. Making less products than calculated possible with the limiting reactant is also a possibility. I hope this helps!
by kristinalaudis3e
Sun Oct 18, 2020 11:32 pm
Forum: Balancing Chemical Reactions
Topic: Syntax Question
Replies: 4
Views: 49

Re: Syntax Question

Yes they are the same! It is essentially like math where if you have something in parentheses and they are multiplied by a number, that number gets distributed to everything inside the parentheses. In this case, (OH) has a subscript of 2, there for it would be distributed to the O and the H to make ...
by kristinalaudis3e
Sun Oct 18, 2020 11:25 pm
Forum: Significant Figures
Topic: How do I know how many sig figs to use?
Replies: 6
Views: 99

Re: How do I know how many sig figs to use?

When you multiply or divide, your answer should have the same number of sig figs as the value with the smallest number of significant figures. 55.5 (3 sig figs) / 2.5 (2 sig figs) = 22.2, but you need only 2 sig figs so it would be 22. When you add or subtract, you answer should have the same number...
by kristinalaudis3e
Sun Oct 18, 2020 8:13 pm
Forum: Balancing Chemical Reactions
Topic: Textbook Problem H.11
Replies: 1
Views: 24

Re: Textbook Problem H.11

For the second stage, I believe those are the right compounds, but you just have to balance them. So from what we know about Fe3O4 + CO -------> Fe + CO2, we can see that there is more Fe on the left than the right. To balance this, we simply add a 3 in front of the Fe on the right to create Fe3O4 +...
by kristinalaudis3e
Sun Oct 18, 2020 7:58 pm
Forum: Significant Figures
Topic: How to use Scientific Notation
Replies: 9
Views: 106

Re: How to use Scientific Notation

They multiply and divide normally. For mw personally, it may be a little more work but I take the terms out of their scientific notation and multiply/divide normally, then put my answer back into scientific notation with the correct number of sig figs. This helps me make sure that I am doing it corr...
by kristinalaudis3e
Sun Oct 11, 2020 5:13 am
Forum: Molarity, Solutions, Dilutions
Topic: Formulas involved in Determining Solution Concentration
Replies: 8
Views: 86

Re: Formulas involved in Determining Solution Concentration

I was also confused about this when doing the sapling homework, as I tried to use m1v1-m2v2 when in reality all I had to do was use m=n/v. I think from that problem I learned that you just have to look closely at what they give you. if the question gives you any 3 parts of the m1v1=m2v2 formula, tha...
by kristinalaudis3e
Sun Oct 11, 2020 5:02 am
Forum: Significant Figures
Topic: Scientific Notation
Replies: 4
Views: 39

Scientific Notation

Should we always be using scientific notation for our answers? I know this question can be a little vague so if anyone has any overall tips for when to use scientific notation/how to use scientific notation I would really appreciate it!
by kristinalaudis3e
Sun Oct 11, 2020 4:58 am
Forum: Significant Figures
Topic: When should I start looking at sig figs?
Replies: 31
Views: 235

Re: When should I start looking at sig figs?

I think for more accuracy, you should keep all the decimals during intermediate steps and then use sig figs for your final result. For example, if you get an answer during step one and then round it and then use that rounded number for step two and so on, the likelihood of error increases between ea...
by kristinalaudis3e
Sun Oct 11, 2020 4:49 am
Forum: Significant Figures
Topic: Sig Fig for numbers like 200, 3300, 4000
Replies: 6
Views: 49

Re: Sig Fig for numbers like 200, 3300, 4000

To begin, there are 4 rules for sig figs. 1. any digit that isn't a 0 is significant 2. any zeros sandwiched between 2 non-zero digits are significant 3. leading zeros aren't significant 4. if there is a decimal point, any zeros trailing a non-zero digit is significant Therefore, 0.005 actually has ...
by kristinalaudis3e
Sun Oct 11, 2020 2:01 am
Forum: Empirical & Molecular Formulas
Topic: Sapling HW#9
Replies: 3
Views: 55

Sapling HW#9

#9 said "Caproic acid has the odor of goats. (In fact, Capra is the genus of the domestic goat.) The compound contains only C, H, and O and was experimentally found to have a molar mass of 110±10 g/mol . When a 1.000 g sample of caproic acid is burned in excess oxygen, 2.275 g CO2 and 0.929 g H...

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