Search found 45 matches

by Jasmine Chow 1F
Thu Feb 07, 2019 11:20 pm
Forum: Phase Changes & Related Calculations
Topic: Units of enthalpy
Replies: 5
Views: 22

Re: Units of enthalpy

Enthalpy is kJ/ mol
by Jasmine Chow 1F
Thu Feb 07, 2019 11:19 pm
Forum: Phase Changes & Related Calculations
Topic: Heat Curve
Replies: 6
Views: 24

Re: Heat Curve

I believe you should memorize it as it will help with bomb Calorimeter problems and other problems with various phase changes. Even if the curve is given I believe it would be helpful to memorize it anyways. It will save you time on the exam.
by Jasmine Chow 1F
Thu Feb 07, 2019 11:18 pm
Forum: Phase Changes & Related Calculations
Topic: Negative work
Replies: 11
Views: 47

Re: Negative work

Yes you can have negative work on a system. An example of this would be the system doing work on its surroundings. Increasing the volume does count as negative work by the system.
by Jasmine Chow 1F
Thu Jan 31, 2019 10:59 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Open, closed, or isolated systems
Replies: 10
Views: 44

Re: Open, closed, or isolated systems

An open system, like a cup of water, can exchange matter and energy with the environment. A closed system, like a closed water bottle, can only exchange energy. A isolated system like a sealed thermos can exchange neither.
by Jasmine Chow 1F
Thu Jan 31, 2019 10:56 pm
Forum: Phase Changes & Related Calculations
Topic: Steam vs Boiling Water
Replies: 10
Views: 50

Re: Steam vs Boiling Water

It takes more energy; in the form of heat; to go from water to steam than it does to go from water to boiling water. Since it takes more energy to go through that phase change you would get a worse burn.
by Jasmine Chow 1F
Thu Jan 31, 2019 10:55 pm
Forum: Phase Changes & Related Calculations
Topic: J vs. kJ
Replies: 9
Views: 33

Re: J vs. kJ

It depends on what the problem specifies. If it does not ask I usually keep the answer in the units the problem gave the values as.
by Jasmine Chow 1F
Thu Jan 24, 2019 1:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5% Rule
Replies: 5
Views: 51

Re: 5% Rule

you can use the 5% rule for a K value that is less than 10^-3 for acids and bases or equilibrium concentrations and pressures.
by Jasmine Chow 1F
Thu Jan 24, 2019 1:39 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: converting between kp and kc
Replies: 4
Views: 25

Re: converting between kp and kc

you will want to use the formula PV=nRT. if you just move the V to the other side you get P=nRT/v. But n/v is just concentration. So you replace n/v with your concentration for kc then you plug in your T and R constant to get P.
by Jasmine Chow 1F
Thu Jan 24, 2019 1:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units
Replies: 2
Views: 21

Units

What is the unit for pressure concentration used in Chem? Is it still molarity?
by Jasmine Chow 1F
Thu Jan 17, 2019 1:25 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Inert Gases
Replies: 5
Views: 44

Re: Inert Gases

Inert gases will not react with a reaction therefore it is not considered when calculating the equilibrium constant equation as nothing is changing for that gas and it is also not changing anything.
by Jasmine Chow 1F
Thu Jan 17, 2019 1:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Changes to K value
Replies: 9
Views: 40

Re: Changes to K value

Temperature is the only modification that can affect the K value. Pressure, volume, and concentration does not affect the K value but it does affect which side of the reaction is favored more.
by Jasmine Chow 1F
Thu Jan 17, 2019 1:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q vs K [ENDORSED]
Replies: 4
Views: 43

Re: Q vs K [ENDORSED]

The Q is the same thing as the K value however it is the constant when the reaction is not in equilibrium. So you often compare K and Q to see which side of the reaction is favored when it is not in equilibrium.
by Jasmine Chow 1F
Fri Jan 11, 2019 7:42 pm
Forum: Ideal Gases
Topic: Pressure of gasses
Replies: 5
Views: 38

Re: Pressure of gasses

I don't think we will be using it. He hasn't mentioned it in lecture yet.
by Jasmine Chow 1F
Fri Jan 11, 2019 7:36 pm
Forum: Ideal Gases
Topic: Pv=nRT [ENDORSED]
Replies: 12
Views: 84

Re: Pv=nRT [ENDORSED]

yes it is in Kelvin. If you need to convert to K from C add 273.
by Jasmine Chow 1F
Fri Jan 11, 2019 7:34 pm
Forum: Ideal Gases
Topic: Q and K [ENDORSED]
Replies: 35
Views: 780

Re: Q and K [ENDORSED]

There is no difference.
by Jasmine Chow 1F
Wed Dec 05, 2018 12:27 pm
Forum: Significant Figures
Topic: Sig Figs in the Middle of a Problem
Replies: 8
Views: 184

Re: Sig Figs in the Middle of a Problem

I would suggest waiting until the very end to round to the nearest sig fig. That way you still get the most accurate answer.
by Jasmine Chow 1F
Wed Dec 05, 2018 12:26 pm
Forum: Empirical & Molecular Formulas
Topic: Determining Empirical formula
Replies: 4
Views: 65

Re: Determining Empirical formula

You should first convert all your elements into moles. you then divide by the smallest mole value to get your empirical equation values. Last multiply if needed to get whole numbers.
by Jasmine Chow 1F
Wed Dec 05, 2018 12:21 pm
Forum: Naming
Topic: Oxidation number
Replies: 2
Views: 28

Re: Oxidation number

Cl will always have a negative 1- charge. So say you have something that says Cl2 then the overall charge will be 2-. In the case of [Fe Cl(OH2)5]^+ you will find the oxidation number of Fe. So Oh2 is a neutral ligand therefore there is no charge from this molecule. Since Cl is the only component th...
by Jasmine Chow 1F
Sat Dec 01, 2018 12:38 am
Forum: Ionic & Covalent Bonds
Topic: Intra vs Intermolecular forces
Replies: 9
Views: 130

Re: Intra vs Intermolecular forces

Intermolecular forces are weaker than intramolecular forces. Therefore it would be easier to break the bond between atoms that make up a molecule than to separate molecules. Intramolecular forces also consist of weak forces such as London dispersion and Van der Waals.
by Jasmine Chow 1F
Sat Dec 01, 2018 12:34 am
Forum: Hybridization
Topic: Delocalized Pi Bonding
Replies: 3
Views: 31

Re: Delocalized Pi Bonding

A delocalized pi bond is when electrons can freely move more that two nuclei. You will often see this in a lewis structure in carbon rings. Carbon rings often consist of double bonds. These pi bonds that are spread out over the lewis structure means the pi bonds are delocalized as they do not reside...
by Jasmine Chow 1F
Sat Dec 01, 2018 12:30 am
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 186
Views: 39179

Re: Saying Thank You to Dr. Lavelle

Thank you so much Dr. Lavelle for all the you do. Your lectures and all your resources have helped me do well and keep up with the class.
by Jasmine Chow 1F
Sat Nov 24, 2018 1:14 am
Forum: Ionic & Covalent Bonds
Topic: Bond Lengths
Replies: 10
Views: 112

Re: Bond Lengths

There is resonance therefore, you take the average of the two.
by Jasmine Chow 1F
Sat Nov 24, 2018 1:11 am
Forum: Administrative Questions and Class Announcements
Topic: How to find my posts
Replies: 28
Views: 15208

Re: How to find my posts

If you click on your account it should show you your post. Also if you had replied to someone there is a section that shows you how many times you have posted. If you click that it will should you all of your posts.
by Jasmine Chow 1F
Sat Nov 24, 2018 1:09 am
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 186
Views: 39179

Re: Saying Thank You to Dr. Lavelle

Thank you Dr. Lavelle for always keeping the class engaging. I also enjoy the fact that you have been using models in class to explain the molecular structure! Looking forward to your 14b lectures next quarter!
by Jasmine Chow 1F
Thu Nov 15, 2018 8:01 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 8
Views: 143

Re: Electronegativity

Electronegativity will increase upward and to the right of the periodic table. Some exceptions include noble gases, lanthanides, and actinides.
by Jasmine Chow 1F
Thu Nov 15, 2018 8:00 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 10
Views: 107

Re: Formal Charge

The formal charge is the best way to ensure your lewis structure is in the most stable state and to find its molecular shape via VSPER. Some ions may throw people off so formal charges are the best way to check your work.
by Jasmine Chow 1F
Thu Nov 15, 2018 7:58 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Memorizing the VSPER Models
Replies: 4
Views: 58

Memorizing the VSPER Models

I am currently trying to memorize all the VSPER models from the chart from the text book. What would be the best way to memorize all the information about the angles and what shapes belong with what?
by Jasmine Chow 1F
Thu Nov 08, 2018 2:52 pm
Forum: Resonance Structures
Topic: Radicals
Replies: 11
Views: 115

Re: Radicals

A radical has lone pairs. Usually a single electron for example the element NH4+.
by Jasmine Chow 1F
Thu Nov 08, 2018 2:50 pm
Forum: Lewis Structures
Topic: Double Bonds
Replies: 7
Views: 83

Re: Double Bonds

I usually check to see if a double bond is needed through the formal charges or through the pairs. If there is an odd number and there is a single lone electron I usually find a way to make it a double bond. Formal charges are the best way to check if another bond is needed.
by Jasmine Chow 1F
Thu Nov 08, 2018 2:48 pm
Forum: Lewis Structures
Topic: Formal charge question
Replies: 9
Views: 100

Re: Formal charge question

Once I see every element has its respective electrons and all the needed bond have been inserted I use the formal charge to solidify the lewis structure is in its most stable form. Its a great way to check your work.
by Jasmine Chow 1F
Tue Oct 30, 2018 9:55 pm
Forum: Trends in The Periodic Table
Topic: Electron affinity
Replies: 3
Views: 59

Re: Electron affinity

Electron affinity represents the energy spent or released when an electron is added to a gaseous molecule to create an ion. An example of this is the electron affinity of chlorine (-349 kJ mol-1) the negative sign represents a release in energy. Electronegativity is the tendency of atoms to attract ...
by Jasmine Chow 1F
Tue Oct 30, 2018 9:48 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: px,py,pz???
Replies: 6
Views: 80

Re: px,py,pz???

x,y, and z represent the different sections of an orbital each pair of elections can fill. These are just ways to distinguish between the different positions within the orbital.
by Jasmine Chow 1F
Tue Oct 30, 2018 9:46 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: How to do e- configuration shorthand?
Replies: 3
Views: 46

Re: How to do e- configuration shorthand?

You would only need to put [Xe] for the shorthand way as it is the closest Nobel gas.
by Jasmine Chow 1F
Tue Oct 23, 2018 11:36 am
Forum: Einstein Equation
Topic: Joules per photon?
Replies: 5
Views: 115

Re: Joules per photon?

You can just leave it in Joules.
by Jasmine Chow 1F
Tue Oct 23, 2018 11:34 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Value of Delta X
Replies: 8
Views: 165

Re: Value of Delta X

The delta x in the equation is usually in meters and is often what is solved for or given. If it is in pm you would need to convert it to m so you can solve the problem.
by Jasmine Chow 1F
Tue Oct 23, 2018 11:32 am
Forum: Properties of Light
Topic: Photoelectric Effect
Replies: 8
Views: 124

Re: Photoelectric Effect

The photoelectric effect is the emission of electrons caused by the threshold of the metal and the energy of the photon.
by Jasmine Chow 1F
Fri Oct 19, 2018 9:05 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Lyman vs Balmer
Replies: 6
Views: 61

Re: Lyman vs Balmer

the Lyman series releases electrons to the n=1 level and is often associated with UV rays, while the Balmer series will release electrons to the n=2 energy level and is often associated with visible light.
by Jasmine Chow 1F
Fri Oct 19, 2018 9:01 pm
Forum: Empirical & Molecular Formulas
Topic: Is it possible for the Empirical and Molecular formula to be the same? [ENDORSED]
Replies: 8
Views: 205

Re: Is it possible for the Empirical and Molecular formula to be the same? [ENDORSED]

yes! if the molecular formula can not be simplified it is the same as the molecular formula.
by Jasmine Chow 1F
Fri Oct 19, 2018 8:58 pm
Forum: Properties of Light
Topic: color of light
Replies: 11
Views: 131

Re: color of light

I have looked at a few sites and many have stated though the frequency and wavelength are inversely proportional to speed of light the wave length is often the indicator of what the color is.
by Jasmine Chow 1F
Wed Oct 10, 2018 8:13 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical & Molecular Formulas
Replies: 11
Views: 320

Empirical & Molecular Formulas

Can the empirical and molecular formula be the same?
by Jasmine Chow 1F
Wed Oct 10, 2018 8:12 pm
Forum: SI Units, Unit Conversions
Topic: Scientific Notation
Replies: 7
Views: 110

Re: Scientific Notation

There really isn't a difference but I would get use to writing in scientific notation as Dr. Lavelle said scientific notation is often used is in the lab. there is no specific time to convert it to scientific notation. I would just automatically make it into scientific notation just in case. It is a...
by Jasmine Chow 1F
Wed Oct 10, 2018 8:09 pm
Forum: Einstein Equation
Topic: sig fig numbers
Replies: 4
Views: 47

sig fig numbers

When you are doing an exam should the final answer be in the lowest number or the highest number of sig figs from the problem?
by Jasmine Chow 1F
Wed Oct 03, 2018 10:04 pm
Forum: Balancing Chemical Reactions
Topic: notation
Replies: 4
Views: 124

Re: notation

Yes he said it is important to do during an exam and it is also good practice once you begin working in labs and doing research.
by Jasmine Chow 1F
Wed Oct 03, 2018 10:03 pm
Forum: Balancing Chemical Reactions
Topic: Balancing reactions tips
Replies: 29
Views: 504

Re: Balancing reactions tips

When I balance equations I like to write the number of elements on both sides so I can see everything visually.

B2O3+Mg ------> MgO+B

B:2 B:1
O:3 O:1
Mg:1 Mg:1

Then you can see where to balance everything out.
by Jasmine Chow 1F
Wed Oct 03, 2018 9:55 pm
Forum: Significant Figures
Topic: Sig Figs?
Replies: 3
Views: 48

Sig Figs?

How do sig figs work?

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