Search found 71 matches

by emwoodc
Sun Feb 07, 2021 11:35 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Delta U
Replies: 6
Views: 41

Re: Delta U

Internal energy is the energy associated with the random motion of molecules within the system!
by emwoodc
Sun Feb 07, 2021 11:33 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: When work and heat should be positive/negative
Replies: 6
Views: 22

Re: When work and heat should be positive/negative

heat = negative when the system is doing work and you are losing heat!
by emwoodc
Sun Feb 07, 2021 11:31 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Using R in thermodynamic equations
Replies: 24
Views: 77

Re: Using R in thermodynamic equations

try to identify the units first when deciding which R to use. All the units are provided on the equations sheet so I wouldn't worry too much about memorizing them! As I solved more problems I realized I could figure out which R to use by the equation I am using and what answer I need to provide.
by emwoodc
Sun Feb 07, 2021 11:28 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: delta U= delta H
Replies: 21
Views: 244

Re: delta U= delta H

This means that when there is constant pressure AND constant volume, delta H (enthalpy) equals delta U
by emwoodc
Sun Feb 07, 2021 11:27 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Cp and Cv
Replies: 7
Views: 40

Re: Cp and Cv

I saw this on a saplings hint and I was lost too! but I did some research and found that Cp-Cv=R!. I'm not sure if it'll come up later but Cp/Cv ratio is also called the heat capacity ratio.
by emwoodc
Sun Feb 07, 2021 11:24 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: types of gas
Replies: 8
Views: 22

Re: types of gas

you would have to draw out the Lewis structure and see if they are linear or not. Atom is pretty self-explanatory.
by emwoodc
Sun Feb 07, 2021 11:23 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Delta U in relation to q
Replies: 5
Views: 30

Re: Delta U in relation to q

Delta U or E is equal to q only when work =0 but I believe the common instance we see delta U equal q is when there is constant volume. I wouldn't worry about it too much.
by emwoodc
Sun Feb 07, 2021 6:31 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: deltaU
Replies: 29
Views: 100

Re: deltaU

Delta U is the change in internal energy of a system. it's equal to the net heat transferred in and out of the system .
by emwoodc
Sun Feb 07, 2021 6:29 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Spontaneous processes
Replies: 7
Views: 39

Re: Spontaneous processes

The second law of thermodynamics states that entropy always increases for a spontaneous process. I'm not exactly sure why but I believe it's because heat flowing into a surrounding would cause the motion of the molecules to increase? this would eventually increase entropy.
by emwoodc
Sun Feb 07, 2021 6:24 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Systems
Replies: 24
Views: 77

Re: Systems

The universe is said to be an isolated system! I believe Professor Lavelle mentioned it briefly during lecture.
by emwoodc
Sun Feb 07, 2021 6:22 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: enthalpy and heat
Replies: 10
Views: 56

Re: enthalpy and heat

Q refers to the energy transfer due to thermal reactions and enthalpy is the total heat content. They are not exchangeable.
by emwoodc
Sun Feb 07, 2021 6:20 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeters
Replies: 10
Views: 25

Re: Calorimeters

So calorimeters are used to measure the heat capacity of materials and this is measured by trapping the heat released from a chemical reaction.
by emwoodc
Sun Jan 24, 2021 10:58 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Ice Tables
Replies: 28
Views: 86

Re: Ice Tables

you use -x when the reaction is going towards the products and you use +x when the reaction is going towards the reactants
by emwoodc
Sun Jan 24, 2021 10:56 pm
Forum: Ideal Gases
Topic: Acids and Bases
Replies: 7
Views: 29

Acids and Bases

Do we have a section for acids and bases?
by emwoodc
Sun Jan 24, 2021 10:55 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H2O as a Gas
Replies: 69
Views: 453

Re: H2O as a Gas

when forming the ICE table it's important to remember that we don't include anything in the solid and liquid form! we definitely include it when it's a gas or aqueous. So for H2O, we would include it if it was a gas!
by emwoodc
Sun Jan 24, 2021 10:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: When to use ICE box
Replies: 23
Views: 102

Re: When to use ICE box

We use ICE boxes when we have an unknown concentration!
by emwoodc
Wed Jan 20, 2021 7:58 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Q and K
Replies: 46
Views: 171

Re: Q and K

You are correct! K is found at equilibrium and Q is found at any time of the reaction!
by emwoodc
Wed Jan 20, 2021 7:56 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Total Pressure
Replies: 26
Views: 106

Re: Total Pressure

the total pressure of a reaction is the sum of all the partial pressures in a reaction.
by emwoodc
Wed Jan 20, 2021 7:54 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature
Replies: 45
Views: 160

Re: Temperature

if the reaction is endothermic it will favor the product formation and if the reaction is exothermic the reaction will favor the reactant formation.
by emwoodc
Wed Jan 20, 2021 7:51 pm
Forum: Ideal Gases
Topic: Inverse Kc [ENDORSED]
Replies: 41
Views: 119

Re: Inverse Kc [ENDORSED]

The inverse Kc is for the inverse reaction ! :)
by emwoodc
Wed Jan 20, 2021 7:45 pm
Forum: Ideal Gases
Topic: Omitting solid/liquid
Replies: 19
Views: 93

Re: Omitting solid/liquid

the concentration of solids and liquids do not change! so when we calculate concentration they're omitted!
by emwoodc
Tue Jan 12, 2021 12:10 am
Forum: Ideal Gases
Topic: Units for Pressure
Replies: 41
Views: 844

Re: Units for Pressure

Dr. Lavelle said that bar is technically the correct unit but since atm is so close to bar you can use atm!
by emwoodc
Tue Jan 12, 2021 12:09 am
Forum: Ideal Gases
Topic: PV=nRT
Replies: 74
Views: 504

Re: PV=nRT

P: pressure
V: volume
n: moles
R: constant
T: temperature
by emwoodc
Tue Jan 12, 2021 12:06 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc vs Kp
Replies: 6
Views: 34

Re: Kc vs Kp

you could yes.
by emwoodc
Tue Jan 12, 2021 12:05 am
Forum: Ideal Gases
Topic: Gas constant R
Replies: 26
Views: 110

Re: Gas constant R

The Gas constant R is always given on the equations sheet and is constant so dw about memorizing it.
by emwoodc
Tue Jan 12, 2021 12:03 am
Forum: Ideal Gases
Topic: Units of Temperature
Replies: 82
Views: 344

Re: Units of Temperature

It would be Kelvin! Dr. Lavelle mentioned it during class.
by emwoodc
Fri Nov 29, 2019 9:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Explain VSEPR conceptually
Replies: 12
Views: 298

Re: Explain VSEPR conceptually

VESPR model is what we name all the models that are in 3D, gives us a more in-depth look at how the molecule is arranged in real life.
by emwoodc
Fri Nov 29, 2019 9:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent Shape
Replies: 31
Views: 1022

Re: Bent Shape

a bent shape can have either one or two lone pairs
by emwoodc
Fri Nov 29, 2019 9:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T-Shape
Replies: 5
Views: 150

Re: T-Shape

in the VSEPR model, you can see that it is not the same.
by emwoodc
Fri Nov 29, 2019 9:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular shape of carbon Dioxide
Replies: 10
Views: 163

Re: Molecular shape of carbon Dioxide

it would be linear
by emwoodc
Fri Nov 29, 2019 9:25 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw Shape
Replies: 12
Views: 182

Re: Seesaw Shape

<90 and <120
by emwoodc
Fri Nov 29, 2019 9:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Test 2
Replies: 6
Views: 146

Re: Test 2

you will probably get your score in discussion
by emwoodc
Fri Nov 29, 2019 9:22 pm
Forum: Hybridization
Topic: Overlapping of Orbitals
Replies: 2
Views: 87

Re: Overlapping of Orbitals

overlapping of bonds equal double and triple bonds.
by emwoodc
Fri Nov 29, 2019 9:21 pm
Forum: Hybridization
Topic: Bond angles
Replies: 2
Views: 87

Re: Bond angles

the reason why these bond angels are less comes from the lone pairs that are pressing the angles down. the only way it would be greater is possibly from removing those lone pairs maybe?
by emwoodc
Fri Nov 29, 2019 9:18 pm
Forum: Hybridization
Topic: Hybridization for elements like S, Xe, Br, etc.
Replies: 4
Views: 113

Re: Hybridization for elements like S, Xe, Br, etc.

hybridization should be the same for every element.
by emwoodc
Fri Nov 29, 2019 9:17 pm
Forum: Hybridization
Topic: double bonds
Replies: 7
Views: 126

Re: double bonds

a double bond would be a sigma and pi bond
by emwoodc
Fri Nov 29, 2019 9:16 pm
Forum: Hybridization
Topic: sigma or pi?
Replies: 20
Views: 404

Re: sigma or pi?

you count the number of bonds there are. for example, a single bond is a sigma bond, a double bond is sigma and pi, and a triple bond is sigma and two pi.
by emwoodc
Fri Nov 29, 2019 9:15 pm
Forum: Hybridization
Topic: Reason for 1 sigma and multiple pi bonds
Replies: 3
Views: 67

Re: Reason for 1 sigma and multiple pi bonds

when you have double and triple bonds, the orbitals are overlapping side by side and this side by side overlap is called pi bonds. Everything overlapping is called pi bonds so the ones that are no overlapping, which only happens once is called sigma bonds.
by emwoodc
Fri Nov 29, 2019 9:14 pm
Forum: Hybridization
Topic: Sigma and Pi bonds
Replies: 7
Views: 158

Re: Sigma and Pi bonds

so the single bonds are sigma bonds, the double bonds are sigma bonds and pi bonds, and triple bonds are one sigma bonds and two pi bonds
by emwoodc
Fri Nov 15, 2019 9:10 am
Forum: Lewis Structures
Topic: Xenon
Replies: 4
Views: 131

Re: Xenon

Xenon has an empty d orbital which allows it to have extended electrons.
by emwoodc
Fri Nov 15, 2019 9:10 am
Forum: Lewis Structures
Topic: Oxygen
Replies: 9
Views: 326

Re: Oxygen

where did you learn that oxygen can only have double bonds
by emwoodc
Fri Nov 15, 2019 9:09 am
Forum: Lewis Structures
Topic: Polar and Non polar covalent bonds in lewis structures
Replies: 5
Views: 86

Re: Polar and Non polar covalent bonds in lewis structures

defining them is not very necessary but knowing what it means should be helpful.
by emwoodc
Fri Nov 15, 2019 9:08 am
Forum: Lewis Structures
Topic: Ground-State Electron Configuration
Replies: 5
Views: 83

Re: Ground-State Electron Configuration

they're the same
by emwoodc
Fri Nov 15, 2019 9:08 am
Forum: Lewis Structures
Topic: Biradical
Replies: 2
Views: 56

Re: Biradical

a biradical is an even compound with two radical centers; however, we didn't really talk about it in class so we shouldn't have to know much about it.
by emwoodc
Fri Nov 15, 2019 9:06 am
Forum: Lewis Structures
Topic: Expanded Octet
Replies: 10
Views: 162

Re: Expanded Octet

elements beyond the 3rd period have extra room to take the extra electrons in! which allows it to be expanded
by emwoodc
Fri Nov 15, 2019 9:04 am
Forum: Lewis Structures
Topic: Lewis Dot Structures
Replies: 7
Views: 110

Re: Lewis Dot Structures

at the point where we are at the lecture, no
by emwoodc
Fri Nov 15, 2019 9:03 am
Forum: Lewis Structures
Topic: Bonds
Replies: 4
Views: 66

Re: Bonds

the strength and length changes when it is a double or triple bond so when you use it you should think about it
by emwoodc
Fri Nov 15, 2019 9:02 am
Forum: Lewis Structures
Topic: Center of a Lewis Structure
Replies: 7
Views: 151

Re: Center of a Lewis Structure

yes, lavelle specified in class that the atom with the lowest ionization energy should be at the center
by emwoodc
Fri Nov 15, 2019 9:02 am
Forum: Lewis Structures
Topic: Lewis Structure
Replies: 6
Views: 96

Re: Lewis Structure

calculate formal charge
by emwoodc
Fri Nov 15, 2019 8:59 am
Forum: General Science Questions
Topic: Test 2
Replies: 20
Views: 304

Re: Test 2

everything after the midterm is covered!
by emwoodc
Mon Oct 21, 2019 4:39 pm
Forum: Properties of Light
Topic: Homework due Next Week
Replies: 9
Views: 158

Re: Homework due Next Week

as long as the topic is still on the topic discussed we should be turning in homework according to it,
by emwoodc
Mon Oct 21, 2019 4:38 pm
Forum: Properties of Light
Topic: Speed of light
Replies: 13
Views: 158

Re: Speed of light

EMR is the speed of light so we typically use it
by emwoodc
Mon Oct 21, 2019 4:36 pm
Forum: SI Units, Unit Conversions
Topic: Unit conversion
Replies: 15
Views: 571

Re: Unit conversion

you use conversion factors!
by emwoodc
Mon Oct 21, 2019 4:35 pm
Forum: SI Units, Unit Conversions
Topic: Calculate using kg or g?
Replies: 13
Views: 492

Re: Calculate using kg or g?

you can't go wrong with always answer using grams and converting early on wouldn't hurt.
by emwoodc
Mon Oct 21, 2019 4:35 pm
Forum: SI Units, Unit Conversions
Topic: Additional Practice
Replies: 2
Views: 149

Re: Additional Practice

for review I don't know if you took AP Chem or not but my AP chem review books gave me a lot of review questions.
by emwoodc
Tue Oct 15, 2019 7:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 1 Solutions
Replies: 4
Views: 275

Re: Test 1 Solutions

I heard most of the test questions are similar to the ones in the homework so if you find the topic and compare solutions it'll be easy to figure out how to solve the problem! if not, going to office hours won't hurt.
by emwoodc
Tue Oct 15, 2019 7:24 pm
Forum: Administrative Questions and Class Announcements
Topic: Discussion about Test questions
Replies: 5
Views: 319

Re: Discussion about Test questions

Everyone is getting their tests back in their discussions this week so it should be okay to talk about them freely
by emwoodc
Tue Oct 15, 2019 7:22 pm
Forum: Administrative Questions and Class Announcements
Topic: Deadline to post
Replies: 7
Views: 492

Re: Deadline to post

it's 5 posts every week and the week ends with sunday night.
by emwoodc
Tue Oct 15, 2019 7:21 pm
Forum: Administrative Questions and Class Announcements
Topic: How to find my posts
Replies: 97
Views: 49773

Re: How to find my posts

click on your own username and you should be able to find all your responses and new topics
by emwoodc
Tue Oct 15, 2019 7:21 pm
Forum: Properties of Light
Topic: Quantum Topic Homework
Replies: 1
Views: 44

Quantum Topic Homework

If we are not done with Quantum Topic 1 by the end of week three, do we just keep turning in questions from that section? just new problems?
by emwoodc
Tue Oct 15, 2019 7:19 pm
Forum: Properties of Light
Topic: Next test
Replies: 23
Views: 463

Re: Next test

TA said we will be getting the equation sheet we got for every test.
by emwoodc
Tue Oct 15, 2019 7:18 pm
Forum: Properties of Light
Topic: 1A.15
Replies: 4
Views: 138

1A.15

Im not entirely sure what the R means in the equation. It throws me off
by emwoodc
Tue Oct 15, 2019 7:15 pm
Forum: Properties of Light
Topic: Variables and what they mean
Replies: 9
Views: 117

Re: Variables and what they mean

lamda is the upside down v with a little edge at the top and it symbolizes wavelength and the v is frequency
by emwoodc
Tue Oct 15, 2019 7:13 pm
Forum: Properties of Light
Topic: Homework
Replies: 11
Views: 139

Re: Homework

i personally did the first 5 questions that were on the homework list and I got full credit
by emwoodc
Sun Oct 06, 2019 11:11 pm
Forum: Significant Figures
Topic: Clarification with sig figs
Replies: 6
Views: 99

Re: Clarification with sig figs

if you round throughout the problem there's a chance that your measurements will be off and the answer will be off
by emwoodc
Sun Oct 06, 2019 11:09 pm
Forum: Significant Figures
Topic: Sig Figs When Adding and Subtracting
Replies: 3
Views: 81

Re: Sig Figs When Adding and Subtracting

when adding or subtracting you use the number with the least sig figs and match the answer to it
by emwoodc
Sun Oct 06, 2019 11:09 pm
Forum: Significant Figures
Topic: Sig Figs in Mulitstep Problems
Replies: 10
Views: 127

Re: Sig Figs in Mulitstep Problems

Yes, if you round the sig figs too early in the problem, it could produce an answer that's one or two numbers off
by emwoodc
Sun Oct 06, 2019 11:07 pm
Forum: Significant Figures
Topic: Rules for Significant Figures
Replies: 4
Views: 113

Re: Rules for Significant Figures

Most of them are mentioned but the one that gets me the most is the rule where if there is a decimal point the zeros after it always counts
by emwoodc
Sun Oct 06, 2019 11:05 pm
Forum: Significant Figures
Topic: Sig Figs in % Yield
Replies: 10
Views: 1321

Re: Sig Figs in % Yield

according to the rounding rule, it should be 64%

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