Search found 73 matches

by Fanny Lee 2K
Sat Mar 16, 2019 9:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E° is not a state function
Replies: 2
Views: 68

E° is not a state function

Why is that sometimes we can add E° values together to get the overall E_cell° even though it not a state function?
by Fanny Lee 2K
Mon Mar 11, 2019 11:09 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: The slope of the tangent line with respect to the rate
Replies: 3
Views: 75

Re: The slope of the tangent line with respect to the rate

We do not need to derive it on the final. However you should know what it represents and why we derive it (to find the instantaneous rate).
by Fanny Lee 2K
Mon Mar 11, 2019 2:05 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Residual Entropy
Replies: 2
Views: 55

Re: Residual Entropy

NO can pack as NO or ON which are clearly identifiable whereas the three F positions in BF3 cannot be distinguished.
by Fanny Lee 2K
Mon Mar 11, 2019 2:00 am
Forum: General Rate Laws
Topic: Solving for the rxn order
Replies: 3
Views: 68

Re: Solving for the rxn order

You would have to make one reactant concentration small and the others large which makes the reaction rate dependent on only the small concentration reactant. Since they are such in large excess, they remain constant.
by Fanny Lee 2K
Mon Mar 11, 2019 1:56 am
Forum: Zero Order Reactions
Topic: Zero Order Reactions
Replies: 7
Views: 250

Re: Zero Order Reactions

Lavelle did not specifically explain what the differences were between the order reactions other than the graphs of the outcome relative to the concentration of reactions. However the differences of order reactions gives insight to the reaction mechanism. The rate of the reactions depend on the reac...
by Fanny Lee 2K
Tue Mar 05, 2019 7:19 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Purpose of Kinetics
Replies: 6
Views: 125

Re: Purpose of Kinetics

Before, we studied thermodynamics which tell us which way a reaction would occur in and its spontaneity. Thermodynamics is the study of energy--does not tell us how fast or slow a reaction is occurring. However with kinetics, it is the study of the rate of reaction.
by Fanny Lee 2K
Tue Mar 05, 2019 7:17 pm
Forum: Phase Changes & Related Calculations
Topic: ISOBARIC
Replies: 3
Views: 69

Re: ISOBARIC

Usually in atm or Torr. Just make sure the units are the same when combining equations together. The constant and formula sheet provided will give you the conversion factors.
by Fanny Lee 2K
Tue Mar 05, 2019 9:41 am
Forum: General Rate Laws
Topic: Overall Order
Replies: 3
Views: 64

Re: Overall Order

The order of reaction of a reactant indicates how much the rate of reaction changes if the concentration of the reactant is changed. It predicts how the reaction speed change over time.
by Fanny Lee 2K
Mon Feb 25, 2019 4:05 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Calculations [ENDORSED]
Replies: 3
Views: 65

Re: Calculations [ENDORSED]

At 0 degrees Celsius, the compound would not have vibrational or rotational entropy but will still have positional/residual entropy. That is why S is the only instance in which the elements at it's most stable form is not 0.
by Fanny Lee 2K
Mon Feb 25, 2019 4:02 pm
Forum: Balancing Redox Reactions
Topic: Balancing redox equations in acidic/basic solutions [ENDORSED]
Replies: 3
Views: 82

Re: Balancing redox equations in acidic/basic solutions [ENDORSED]

The question should tell you whether or not it is an acidic or basic solution
by Fanny Lee 2K
Mon Feb 25, 2019 4:00 pm
Forum: Balancing Redox Reactions
Topic: Water in Redox Reactions [ENDORSED]
Replies: 3
Views: 79

Re: Water in Redox Reactions [ENDORSED]

We add water in acidic solutions. The amount of the moles depend on how much oxygens in the reactant side. Balance the reactants with the corresponding number of hydrogens from water.
by Fanny Lee 2K
Tue Feb 19, 2019 11:47 am
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Entropy at 0 K
Replies: 6
Views: 260

Re: Entropy at 0 K

When the entropy is at 0, it forms a perfect crystal. However, it still has some positional entropy. Higher entropy levels would result in higher rotational and vibrational entropy.
by Fanny Lee 2K
Tue Feb 19, 2019 11:44 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Microstates
Replies: 7
Views: 307

Re: Microstates

You must take an account that microstates must occur within the same energy in order to calculate entropy.
by Fanny Lee 2K
Tue Feb 19, 2019 11:41 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: System vs Surroundings
Replies: 7
Views: 273

Re: System vs Surroundings

Simply, the system is the object you are observing and the surrounding is everything else.
by Fanny Lee 2K
Mon Feb 11, 2019 2:39 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Statistical vs Residual Entropy
Replies: 4
Views: 87

Re: Statistical vs Residual Entropy

I don't think it's a major focus of the midterm but possibly!!!
by Fanny Lee 2K
Mon Feb 11, 2019 2:35 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond enthalpies
Replies: 10
Views: 161

Re: Bond enthalpies

105085381 wrote:Will the bond dissociation energies definitely be given?

The bond dissociation energies will definitely be given but they are given in positive values assuming bonds are broken. Be sure to be careful with the signs when applying it in the midterm and final.
by Fanny Lee 2K
Mon Feb 11, 2019 2:31 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Conversions
Replies: 4
Views: 102

Re: Conversions

Yes the constants and equation sheet is updated since 14A and includes conversions from atm.L to joules. However the sheet also gives the ideal gas constants in which you can convert using those constants to find the correct units.
by Fanny Lee 2K
Wed Feb 06, 2019 3:52 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Isothermal reaction
Replies: 3
Views: 108

Re: Isothermal reaction

An isothermal process is a change of a system, in which the temperature remains constant: ΔT = 0. A non isothermal process is when the temperature is not constant.
by Fanny Lee 2K
Wed Feb 06, 2019 3:49 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Isochoric
Replies: 4
Views: 84

Re: Isochoric

Adiabatic system is when delta q = 0
isochoric system is when delta v =0
isobaric system is when delta p = 0
by Fanny Lee 2K
Wed Feb 06, 2019 3:43 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Why does q=-w?
Replies: 1
Views: 53

Re: Why does q=-w?

In an isothermal reversible reaction, the delta U is equal to 0. Given the equation delta U = q + w, q would equal -w.
by Fanny Lee 2K
Mon Jan 28, 2019 2:52 pm
Forum: Phase Changes & Related Calculations
Topic: State properties
Replies: 3
Views: 59

Re: State properties

For example volume, if you have 10 L of water then add 7 L and removed 3 L, you will end up with 14 L left while the overall change in of water would be 3L even thought there were changes in the intermediate steps. With this example, it shows that state functions does not depend on the steps in-betw...
by Fanny Lee 2K
Mon Jan 28, 2019 2:44 pm
Forum: Phase Changes & Related Calculations
Topic: Steam
Replies: 11
Views: 200

Re: Steam

When steam gets into contact with the air, doesn't it cool down immediately?
by Fanny Lee 2K
Mon Jan 28, 2019 2:36 pm
Forum: Ideal Gases
Topic: Q and K
Replies: 13
Views: 229

Re: Q and K

Q is used to compare to K when at equilibrium. It tells us which way the non-equilbrium solution will shift in order to reach equilibrium. When this state is reached, Q = K.
by Fanny Lee 2K
Tue Jan 22, 2019 12:14 am
Forum: Ideal Gases
Topic: ICE table
Replies: 11
Views: 347

Re: ICE table

Unlike molarity which only limits us to use the ICE table using concentrations, partial pressures can allow for bar or atm as long as you are consistent with the units throughout.
by Fanny Lee 2K
Tue Jan 22, 2019 12:08 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: autoprotolysis
Replies: 2
Views: 45

Re: autoprotolysis

Autoprotolysis is happening automatically in aqueous solutions. Lavelle talked about how in weak acids and bases, this concept can play a role of their concentration on the pH as a whole. If values are smaller than 10^-7, their effect is not great enough to change the pH from its neutral state.
by Fanny Lee 2K
Tue Jan 22, 2019 12:01 am
Forum: Identifying Acidic & Basic Salts
Topic: Effect of pH
Replies: 2
Views: 239

Re: Effect of pH

If I remember correctly Dr. Lavelle noted that the group II elements would affect the pH slightly but not significant enough so that the pH is affected. Keep in mind that sometimes the textbook would write equations using the double arrows for the 2+ cation.
by Fanny Lee 2K
Mon Jan 14, 2019 5:22 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids and Liquids in K
Replies: 4
Views: 83

Re: Solids and Liquids in K

Solids do not have a concentration, it can only be measured by mass and density. Pure liquids take part in very little of the reaction so the outcome of the liquid is quite insignificant. Dr. Lavelle used an analogy in class that explained this concept well: if you have a million dollars and you giv...
by Fanny Lee 2K
Mon Jan 14, 2019 5:15 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Module 4 Post Assessment #14
Replies: 3
Views: 101

Re: Module 4 Post Assessment #14

Adding water to the reactants will cause the yield of the products (in this case C6H12O6 and O2) to increase as well. If the partial pressure of CO2 is decreased, it will cause the products to decrease to make up for the loss of the partial pressure from the reactants.
by Fanny Lee 2K
Mon Jan 14, 2019 3:00 pm
Forum: Administrative Questions and Class Announcements
Topic: Test Dates
Replies: 3
Views: 90

Re: Test Dates

This is the link to his test dates:
https://lavelle.chem.ucla.edu/wp-conten ... hedule.pdf
The topics tested on each of the quizzes is not cumulative--meaning that it quizzes only material after each quiz. However, midterms and finals are indeed cumulative.
by Fanny Lee 2K
Mon Jan 14, 2019 2:51 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Quadratic Formula in Equilibrium
Replies: 4
Views: 70

Re: Quadratic Formula in Equilibrium

Going off from the response above, if the value of Kc is not less than 10^-4, then you must solve for the x value using the quadratic equation (cannot use shortcut). Dr. Lavelle included the rule about quadratic and cubic to help us when dealing with math equations with these properties.
by Fanny Lee 2K
Tue Jan 08, 2019 11:36 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Solids do not have concentrations?
Replies: 3
Views: 56

Re: Solids do not have concentrations?

yes, solids can be measured by mass and density. There is no such thing as a concentration of a solid.
by Fanny Lee 2K
Tue Jan 08, 2019 11:33 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Water in equilibrium constants
Replies: 4
Views: 56

Re: Water in equilibrium constants

Pure liquids (such as the solvent water) are not considered in the k expression since there is such a large excess and the amount used in the reaction is a very small amount, we can say that the concentrations do not change significantly. If the concentrations were used to find the equilibrium const...
by Fanny Lee 2K
Tue Jan 08, 2019 11:27 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Aqueous in K expression
Replies: 4
Views: 90

Re: Aqueous in K expression

If given both aqueous and gases, convert the pressure of the gas into a concentration unit using the ideal gas law.
by Fanny Lee 2K
Tue Jan 08, 2019 11:20 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kc vs Kp
Replies: 4
Views: 56

Re: Kc vs Kp

When you're given both units of concentration and units of pressure in an equilibrium equation, you must convert the units of pressure into units of concentration using the ideal gas law.
by Fanny Lee 2K
Mon Dec 03, 2018 2:58 pm
Forum: Naming
Topic: Order of Ligand Naming
Replies: 6
Views: 99

Re: Order of Ligand Naming

With a transition metal, it appears first in the coordination compound formula. However when you name it with the ligands, it appears last, after the ligands alphabetically.
by Fanny Lee 2K
Mon Dec 03, 2018 2:48 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Negative pH?
Replies: 5
Views: 90

Re: Negative pH?

Since the equation to calculate the pH is -log, the negative sign ensures that the value of pH is positive.
by Fanny Lee 2K
Mon Dec 03, 2018 2:46 pm
Forum: Lewis Acids & Bases
Topic: Lewis vs. Bronsted
Replies: 5
Views: 145

Re: Lewis vs. Bronsted

It's good to know that Lewis acid and bases are the "bigger" categories that encompasses the Bronsted acid and bases. Generally speaking, a Bronsted acid and base and be a lewis acid a base, but the lewis acid and base does not necessarily have to be Bronsted
by Fanny Lee 2K
Tue Nov 27, 2018 9:51 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Double Bonds as Regions of Electron Density
Replies: 5
Views: 77

Re: Double Bonds as Regions of Electron Density

Lone pairs are also considered regions of electron density!
by Fanny Lee 2K
Tue Nov 27, 2018 9:38 am
Forum: Determining Molecular Shape (VSEPR)
Topic: General question on Molecular Shape
Replies: 2
Views: 40

Re: General question on Molecular Shape

I would first draw out the lewis dot structure and use the steric numbers to determine the VSEPR shape of the molecule. If it is linear, trigonal planar, square planar, T shaped, and bent, then it is on the same plane. If the VSEPR shape is drawn using wedges, then it does not lie on the same plane.
by Fanny Lee 2K
Tue Nov 27, 2018 9:33 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecule Shape for HCN
Replies: 2
Views: 94

Re: Molecule Shape for HCN

Yes, HCN is linear. The bent shape only applies to lone pairs on the central atom. The lone pairs on the central atom have a stronger repulsion and thus push the two other bonds slightly closer together.
by Fanny Lee 2K
Mon Nov 19, 2018 12:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pair distortion
Replies: 2
Views: 56

Re: Lone Pair distortion

Bond angles will deviate from their ideal values according to the rule that lone pairs repel other electrons more strongly than bonding pairs. Being closer to the central atom causes lone-pairs take up more of the available 'bonding space'. Remember that lone-lone pair > lone-bonding pair > bonding-...
by Fanny Lee 2K
Mon Nov 19, 2018 12:35 pm
Forum: Ionic & Covalent Bonds
Topic: delta positive delta negative
Replies: 15
Views: 363

Re: delta positive delta negative

The more electronegative atom is the delta negative and the less electronegative atom is delta positive. The dipole moment is from the positive to the negative.
by Fanny Lee 2K
Mon Nov 19, 2018 12:28 pm
Forum: Dipole Moments
Topic: Polarity and Nonpolarity of the Same Molecule
Replies: 2
Views: 56

Re: Polarity and Nonpolarity of the Same Molecule

The individual intermolecular bonds can be polar within a molecule but in some cases if you look at the entire molecule as a whole, these dipole moments can cancel each other out, making the overall molecule non-polar while consisting of individual polar bonds. How the compounds are rearranged can d...
by Fanny Lee 2K
Tue Nov 13, 2018 8:49 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Formula
Replies: 3
Views: 68

Re: VSEPR Formula

In the VSEPR formulas, "A" stands for a central atom, "X" for an attached atom, and "E" for a lone pair.
by Fanny Lee 2K
Tue Nov 13, 2018 10:44 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs. NonPolar
Replies: 5
Views: 121

Re: Polar vs. NonPolar

Depending on where an element is on the periodic table, you can estimate how strong the electronegativity is. The larger the difference, the more polar since elements on the upper right is more electronegative than the upper left elements. Another ways is to see if the structure of the molecule is s...
by Fanny Lee 2K
Mon Nov 12, 2018 11:18 pm
Forum: Ionic & Covalent Bonds
Topic: What is Distortion?
Replies: 3
Views: 63

Re: What is Distortion?

Without the interactions of other atoms/molecules, the arrangement of electrons within the electron cloud would be symmetrical. Since the force is introduced, the electron cloud can be distorted, meaning it is shifted to one side. Depending on which atom has the stronger polarizing power or polariza...
by Fanny Lee 2K
Mon Nov 12, 2018 4:02 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Distortion
Replies: 3
Views: 103

Re: Distortion

polarizability applies to anions and polarization power applies to cations. The bigger the atom, the bigger the distortion.
by Fanny Lee 2K
Mon Nov 12, 2018 3:57 pm
Forum: Administrative Questions and Class Announcements
Topic: Step Up Sessions
Replies: 2
Views: 121

Re: Step Up Sessions

yes campus is closed so no sessions for 11/12
by Fanny Lee 2K
Tue Nov 06, 2018 12:26 am
Forum: Octet Exceptions
Topic: Octet Exceptions
Replies: 4
Views: 104

Re: Octet Exceptions

Elements in period 3 or lower on the periodic table can have an expanded octet. Elements H, He, Li, Be, and group 13 can have incomplete octets. Elements in the 2p orbital can only have an octet.
by Fanny Lee 2K
Tue Nov 06, 2018 12:22 am
Forum: Lewis Structures
Topic: BH4-
Replies: 2
Views: 138

Re: BH4-

Always try to have the charges in the outer elements of the Lewis Structure and have the anions on the element that is most electronegative.
by Fanny Lee 2K
Tue Nov 06, 2018 12:19 am
Forum: Trends in The Periodic Table
Topic: Electronegativity vs. Electron Affinity?
Replies: 11
Views: 377

Re: Electronegativity vs. Electron Affinity?

If an element has a high electronegativity, does that mean it has higher electron affinity?
by Fanny Lee 2K
Wed Oct 31, 2018 12:40 am
Forum: Lewis Structures
Topic: Lewis Structure of BrF3 [ENDORSED]
Replies: 3
Views: 229

Re: Lewis Structure of BrF3 [ENDORSED]

Since Br fills up the 4p orbital, it can have more than an octet.
by Fanny Lee 2K
Mon Oct 29, 2018 1:29 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: 4f, 5d, and 6s orbitals
Replies: 2
Views: 232

Re: 4f, 5d, and 6s orbitals

I'm pretty sure all of Group 6 and Group 11 elements are also part of the exception. I'm curious about your second question too, if anyone would please explain?
by Fanny Lee 2K
Mon Oct 29, 2018 1:25 pm
Forum: Administrative Questions and Class Announcements
Topic: Exam
Replies: 7
Views: 259

Re: Exam

Allotted time is two hours!
by Fanny Lee 2K
Mon Oct 29, 2018 1:19 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Finding Formal Charge
Replies: 3
Views: 101

Re: Finding Formal Charge

Knowing the formal charge on a particular atom in a structure is an important part of keeping track of the electrons and is important for establishing and predicting the reactivity. The formal charge on an atom in a molecule reflects the electron count associated with the atom compared to the isolat...
by Fanny Lee 2K
Mon Oct 22, 2018 1:32 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra Module 41
Replies: 1
Views: 35

Re: Atomic Spectra Module 41

The correct answer should be b because it releases more energy from n=5 to n=1 than n=4 to n=1. Since more energy is released, the wavelength of should be shorter for n=5 to n=1 than from n=4 to n=1.
by Fanny Lee 2K
Mon Oct 22, 2018 12:53 pm
Forum: Properties of Electrons
Topic: Transitions
Replies: 3
Views: 142

Re: Transitions

The electron absorbs energy and moves to a higher energy level. It then produces a line emission spectrum when it moves back down to a lower energy level (goes from an excited state to the ground state) and releases energy. The energy released is negative and should equal to the amount of energy put...
by Fanny Lee 2K
Mon Oct 22, 2018 12:41 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals
Replies: 2
Views: 89

Re: Orbitals

You would use the Rydberg Equation 1/λ = RZ2(1/n12 - 1/n22) and figure out the wavelength. N2 and n1 is related to the principal quantum number or energy quantum number. This formula works very well for transitions between energy levels of a hydrogen atom with only one electron. Use the initial ener...
by Fanny Lee 2K
Mon Oct 15, 2018 8:00 pm
Forum: Properties of Light
Topic: Lecture
Replies: 1
Views: 44

Re: Lecture

Lectures should be the same! Lavelle has lectures at 10am-10:50, 12pm-12:50, and 2pm-2:50pm
by Fanny Lee 2K
Mon Oct 15, 2018 5:54 pm
Forum: Properties of Light
Topic: Problem 1.21 6th Ed.
Replies: 1
Views: 37

Re: Problem 1.21 6th Ed.

Yes you touched upon the important aspects of what the photoelectric effect shows in which electromagnetic radiation has the properties of particles. Albert Einstein suggested that light consisted of particles (or packets) of energy called photons. The energy of the photon has energy when you multip...
by Fanny Lee 2K
Mon Oct 15, 2018 5:47 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Question 1.15 sixth edition
Replies: 10
Views: 164

Re: Question 1.15 sixth edition

To find the n values of the orbitals, you need to use the Rydberg equation: v=R((1/n(Initial)^2)-(1/n(Final)^2). First you need to find the frequency which you calculated as 2.922 x 10^15 s^-1. Plug in the frequency and n(initial) as 1. solve for n(final)^2 which should equal to 9. If we want to fin...
by Fanny Lee 2K
Wed Oct 10, 2018 1:34 pm
Forum: Empirical & Molecular Formulas
Topic: Question F13 ??
Replies: 2
Views: 161

Re: Question F13 ??

Hey Tyra, 5Cl and Cl5 are both the same thing but if you're comparing in terms of molar ratios, the form of 5Cl would be best. Technically speaking, both contain 5 moles of Chlorine. Also on the quiz, you don't need to know how to name to molecule/compounds, but definitely on future tests! Hope this...
by Fanny Lee 2K
Mon Oct 08, 2018 7:46 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity Question G5
Replies: 2
Views: 65

Re: Molarity Question G5

Hello!
You would use the formula Molarity = number of moles / volume (L). The reason we use this formula as opposed to the other one is that this question is asking for volume, not relating to dilution.
by Fanny Lee 2K
Mon Oct 08, 2018 7:39 pm
Forum: Properties of Light
Topic: Wavelength vs Frequency
Replies: 7
Views: 112

Re: Wavelength vs Frequency

The wavelength is the distance between the peaks or trouphs of a wave. The frequency is how many waves occur within a given time. The wavelength and frequency of light are closely related. The higher the frequency, the shorter the wavelength. Because all light waves move through a vacuum at the same...
by Fanny Lee 2K
Mon Oct 08, 2018 6:46 pm
Forum: Significant Figures
Topic: significant figures
Replies: 5
Views: 369

Re: significant figures

Your result will be 15.00

-Hope this helps :)
by Fanny Lee 2K
Mon Oct 08, 2018 6:41 pm
Forum: Empirical & Molecular Formulas
Topic: M19
Replies: 3
Views: 168

Re: M19

The professor said that anything on the test relating to naming compounds are given to you. However once we learn about the composition of the molecules and the names associated with it, then we are expected to know the formula.
by Fanny Lee 2K
Mon Oct 08, 2018 5:14 pm
Forum: Photoelectric Effect
Topic: Rydberg constant
Replies: 3
Views: 57

Re: Rydberg constant

Hello,
If you purchased the periodic table sheet with the formulas in the back, the Rydberg constant is listed on it. I'm not sure if Lavelle would allow us to use it considering the tests are closed book and notes! It doesn't hurt to memorize it :)
by Fanny Lee 2K
Mon Oct 08, 2018 5:10 pm
Forum: Administrative Questions and Class Announcements
Topic: How do the post hw points work
Replies: 5
Views: 148

Re: How do the post hw points work

I'm pretty sure it is due for the end of this week but to be 100% sure, email your TA and ask them for clarification!
by Fanny Lee 2K
Wed Oct 03, 2018 7:36 pm
Forum: SI Units, Unit Conversions
Topic: Week 2 homework
Replies: 2
Views: 77

Re: Week 2 homework

Hello! I believe we should be moving onto new topics for week two's homework. I'm aware that those who have discussion sessions earlier in the week have an disadvantage but I would suggest reviewing some of the content in the textbook and browsing Dr. Lavelle's website for helpful modules for help o...
by Fanny Lee 2K
Wed Oct 03, 2018 7:21 pm
Forum: Limiting Reactant Calculations
Topic: hi stuck again
Replies: 3
Views: 119

Re: hi stuck again

First you would balance the equation: C6H9Cl3 + 3AgNO3 --> 3AgCl + C6H9(NO3)3. Next, use the given masses of the reactants, convert 0.750 grams of C6H9Cl3 and 1000 grams of AgNO3 to moles by dividing by its molar mass. You should get 0.004 moles of C6H9Cl3 and 5.887 moles of AgNO3. Then determine th...
by Fanny Lee 2K
Tue Oct 02, 2018 7:45 pm
Forum: Molarity, Solutions, Dilutions
Topic: Fundamental E.1
Replies: 1
Views: 74

Re: Fundamental E.1

You need to double it to find the diameter!
by Fanny Lee 2K
Tue Oct 02, 2018 7:43 pm
Forum: Limiting Reactant Calculations
Topic: Confusion on Post-Module Assessment Q18?
Replies: 1
Views: 74

Re: Confusion on Post-Module Assessment Q18?

With the equation balanced, convert the two given grams to moles by dividing it by its molar mass. For NH3 you should get 1.26 moles and for O2 you should get 1.33 moles. Looking back at the balanced equation, there are 4 moles of NH3 and 5 moles of O2. Divide 1.26 moles by 4 and 1.33 moles by 5. Yo...
by Fanny Lee 2K
Tue Oct 02, 2018 7:35 pm
Forum: General Science Questions
Topic: Limiting Reactant Calculations
Replies: 2
Views: 161

Re: Limiting Reactant Calculations

First start of by balancing the equation and you should get C6H9Cl3 + 3AgNO3 --> 3AgCl + C6H9(NO3)3. Make sure the given masses of the reactants are converted into grams. In this case, 1.000 kg is equal to 1000 grams. Convert the grams to moles by dividing it by the molar mass. Determine the limitin...

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