Search found 54 matches

by Doreen Liu 4D
Tue Dec 03, 2019 7:48 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Weak Acid
Replies: 2
Views: 21

Weak Acid

Hydrofluoric acid is a weak acid. Which of the following images best represents a solution of hydrofluoric acid? The blue spheres represent fluorine and the white spheres, hydrogen.

The answer is the one without any bonds - why is that true?
by Doreen Liu 4D
Tue Dec 03, 2019 7:44 pm
Forum: Bronsted Acids & Bases
Topic: Homework J.23
Replies: 1
Views: 21

Homework J.23

The oxides of nonmetallic elements are called acidic oxides because they form acidic solutions in water. Write the balanced chemical equations for the reaction of 1 mol of formula units of each acidic oxide with 1 mol of water molecules to form an oxo- acid and name the acid formed: (a) CO2; (b) SO3.
by Doreen Liu 4D
Tue Dec 03, 2019 6:02 pm
Forum: Conjugate Acids & Bases
Topic: 6.13 Homework
Replies: 1
Views: 31

6.13 Homework

Draw the Lewis structure of boric acid, B(OH)3. (a) Is resonance important for its description? (b) The proton transfer equilibrium for boric acid is given in a footnote to Table 6C.1. In that reaction does boric acid act as a Lewis acid, a Lewis base, or neither? Justify your answer by using Lewis ...
by Doreen Liu 4D
Mon Dec 02, 2019 7:29 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentates
Replies: 1
Views: 17

Polydentates

Why is CO3^2- a tridentate ligand while Oxalate (C2O4^2-) is a bidentate not a tetradentate ligand?
by Doreen Liu 4D
Mon Dec 02, 2019 7:20 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Water as Monodente
Replies: 1
Views: 18

Water as Monodente

Why is water always a monodentate ligand if it has two lone pairs on the Oxygen atom?
by Doreen Liu 4D
Tue Nov 26, 2019 2:39 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity Formula / Calculation
Replies: 5
Views: 75

Re: Molarity Formula / Calculation

The two molarity formula that would be most helpful is: M=n/L and M1V1=M2V2, where n= number of moles, L = liter, M=molarity
by Doreen Liu 4D
Tue Nov 26, 2019 2:37 pm
Forum: Significant Figures
Topic: Sig Figs on Tests
Replies: 24
Views: 284

Re: Sig Figs on Tests

You should calculate/round to the fewest number of sig figs given in a problem.
by Doreen Liu 4D
Tue Nov 26, 2019 2:36 pm
Forum: Industrial Examples
Topic: Difference between biological and industrial examples?
Replies: 3
Views: 54

Re: Difference between biological and industrial examples?

Biological examples would be the body's natural response while industrial examples could be pharmaceuticals.
by Doreen Liu 4D
Tue Nov 26, 2019 2:33 pm
Forum: Biological Examples
Topic: Cisplatin
Replies: 8
Views: 41

Re: Cisplatin

Its structure helps it to bind to DNA molecules and prevent replication.
by Doreen Liu 4D
Tue Nov 26, 2019 2:32 pm
Forum: Naming
Topic: Naming
Replies: 3
Views: 31

Re: Naming

In a coordination compound, the ligands are named before the metal. Write down the names of the ligands in the following order: neutral, negative, positive.
by Doreen Liu 4D
Tue Nov 26, 2019 2:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw Shape
Replies: 12
Views: 77

Re: Seesaw Shape

The angle would be <90.
by Doreen Liu 4D
Tue Nov 19, 2019 9:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Big Molecule
Replies: 2
Views: 27

Big Molecule

How do we draw the lewis structure for CH3CHCHCN?
by Doreen Liu 4D
Tue Nov 19, 2019 9:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Section 2E #27a
Replies: 1
Views: 29

Section 2E #27a

What would be the Lewis Structure of C5H5N? Would we have to know how to draw that on the test?
by Doreen Liu 4D
Tue Nov 19, 2019 8:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: HW 2F:21a
Replies: 2
Views: 27

HW 2F:21a

Can someone explain how to determine the shape and angle of the molecule C2H4?
by Doreen Liu 4D
Tue Nov 19, 2019 8:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: See-Saw Shape
Replies: 3
Views: 28

See-Saw Shape

For a see-saw shape (AX4E), would the angles be <90?
by Doreen Liu 4D
Tue Nov 19, 2019 8:44 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2.45 Homework Question
Replies: 1
Views: 31

2.45 Homework Question

Can someone help me with the lewis structure of the molecule H2C double bonded to CHCHO?
by Doreen Liu 4D
Tue Nov 19, 2019 8:43 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E: Question 29
Replies: 3
Views: 24

Re: 2E: Question 29

The dipole moment for 1 would be the largest because the C-Cl bond vectors are pointing most nearly in the same direction in 1 whereas in 2 the C-Cl vectors point more away from each other, giving a larger cancellation of dipole.
by Doreen Liu 4D
Tue Nov 12, 2019 9:55 pm
Forum: *Shrodinger Equation
Topic: Shrodinger Equation
Replies: 4
Views: 41

Re: Shrodinger Equation

It describes the wave function or state function of a quantum-mechanical system
by Doreen Liu 4D
Tue Nov 12, 2019 9:54 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Magnetic Quantum numbers
Replies: 13
Views: 107

Re: Magnetic Quantum numbers

The magnetic quantum numbers is the -l to l values. If l=1, then ml would be -1, 0, and 1.
by Doreen Liu 4D
Tue Nov 12, 2019 9:53 pm
Forum: DeBroglie Equation
Topic: unit of wavelength
Replies: 5
Views: 76

Re: unit of wavelength

The unit is most likely in meters.
by Doreen Liu 4D
Tue Nov 12, 2019 9:52 pm
Forum: Dipole Moments
Topic: Dipole Moments
Replies: 4
Views: 32

Dipole Moments

Do CH3Cl, CH2Cl2, and CHCl3 all have dipole moments because of the lone pairs on the chlorine?
by Doreen Liu 4D
Tue Nov 12, 2019 9:49 pm
Forum: Bond Lengths & Energies
Topic: Bond lengths in molecules
Replies: 7
Views: 46

Re: Bond lengths in molecules

A double and triple bond is stronger but shorter than a single bond. The stronger the bond, the harder it is to break - so it would take more energy to break a double/triple bond than a single bond.
by Doreen Liu 4D
Tue Nov 12, 2019 9:48 pm
Forum: Dipole Moments
Topic: Intermolecular Forces
Replies: 6
Views: 34

Intermolecular Forces

Which has a higher boiling point? CHI3 or CHF3?
by Doreen Liu 4D
Wed Nov 06, 2019 2:59 pm
Forum: Lewis Structures
Topic: Expanded Octets
Replies: 6
Views: 36

Re: Expanded Octets

For some elements, expanded octets are not allowed (i.e. some period 2 elements), so just be careful when you're drawing those.
by Doreen Liu 4D
Wed Nov 06, 2019 11:52 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Probability
Replies: 3
Views: 51

Re: Probability

The p and d orbitals are not symmetrical and s orbital is symmetrical.
by Doreen Liu 4D
Wed Nov 06, 2019 11:49 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Midterm
Replies: 6
Views: 90

Re: Midterm

It is good to know the experiments because they will provide an understanding of what you are actually solving for.
by Doreen Liu 4D
Wed Nov 06, 2019 11:48 am
Forum: Properties of Light
Topic: Rydberg Equation
Replies: 5
Views: 82

Re: Rydberg Equation

I think we just have to know that the Lyman series corresponds to UV while the Balmer series corresponds to the visible light.
by Doreen Liu 4D
Tue Nov 05, 2019 3:20 pm
Forum: Properties of Electrons
Topic: Multi-electron atom
Replies: 2
Views: 39

Multi-electron atom

What are some of the factors affecting the energy of an electron in a many-electron atom?
by Doreen Liu 4D
Tue Nov 05, 2019 3:04 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectroscopy vs. Molecular Spectroscopy
Replies: 1
Views: 25

Atomic Spectroscopy vs. Molecular Spectroscopy

Can someone explain the difference between Atomic and Molecular spectroscopies?
by Doreen Liu 4D
Tue Oct 29, 2019 10:14 pm
Forum: Resonance Structures
Topic: Resonance Clarification
Replies: 8
Views: 45

Re: Resonance Clarification

Some Lewis Structures have multiple bonds (double/triple bonds) in different equivalent locations. You have resonance when you can place multiple bonds in different places (i.e. the placement of the double bonds)
by Doreen Liu 4D
Tue Oct 29, 2019 10:03 pm
Forum: Lewis Structures
Topic: Formal Charge
Replies: 2
Views: 20

Formal Charge

The formal charge equation is FC=V-(L+S/2) where V=valence electrons and L=lone pairs. What is the "S" in the equation?
by Doreen Liu 4D
Tue Oct 29, 2019 9:28 pm
Forum: Lewis Structures
Topic: Complex Lewis Structures
Replies: 1
Views: 15

Complex Lewis Structures

Can someone explain what the process is when trying to draw a complex Lewis Structure? For example, the lewis structure for section 2B question 11 part c - glycine.
by Doreen Liu 4D
Tue Oct 29, 2019 9:26 pm
Forum: Lewis Structures
Topic: Homework Problem 2B.9(b)
Replies: 2
Views: 18

Homework Problem 2B.9(b)

When drawing the lewis structure of Potassium Phosphide, do we connect the K+ together or do we separate them around the P^3- structure?
by Doreen Liu 4D
Wed Oct 23, 2019 11:14 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Spin Quantum Number
Replies: 6
Views: 30

Spin Quantum Number

I know that the spin quantum (ms) describes the angular momentum of an electron, but I am confused on when to use that number +1/2 and -1/2 or is it only for drawing the arrows?
by Doreen Liu 4D
Wed Oct 23, 2019 11:11 am
Forum: Photoelectric Effect
Topic: post module assignment Q 19
Replies: 4
Views: 34

Re: post module assignment Q 19

The answer should be D. None of the other ones is a correct representation of the photoelectric effect.
by Doreen Liu 4D
Wed Oct 23, 2019 11:09 am
Forum: Properties of Light
Topic: Constant for Speed of Light
Replies: 14
Views: 86

Re: Constant for Speed of Light

In the solutions manual, often the value 2.99x10^8 is used, so I think for accuracy purposes, use the 2.99 value on the test.
by Doreen Liu 4D
Wed Oct 23, 2019 11:07 am
Forum: Properties of Light
Topic: Destructive Interference
Replies: 3
Views: 39

Re: Destructive Interference

Destructive interference can only happen when the trough of one wave meets the peak of another wave. In other words, if they are the "opposite," then they will cancel out.
by Doreen Liu 4D
Wed Oct 23, 2019 11:05 am
Forum: Properties of Light
Topic: Photons
Replies: 3
Views: 33

Re: Photons

No, photons do not have a mass. They do have energy and momentum, but no mass.
by Doreen Liu 4D
Thu Oct 17, 2019 6:24 pm
Forum: DeBroglie Equation
Topic: De Broglie Problem
Replies: 4
Views: 23

De Broglie Problem

A baseball must weigh between 5 and 5.25 ounces. What is the wavelength of a 5.15 ounce ball thrown at 92mph.
Can someone help me with this problem? Also, would I have to turn both the ounces and the miles/hour into SI units before I can start solving it?
by Doreen Liu 4D
Thu Oct 17, 2019 6:20 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: magnetic quantum number, ml
Replies: 2
Views: 15

Re: magnetic quantum number, ml

The magnetic quantum number represents the number of orbitals in each subshell (-l to l)
by Doreen Liu 4D
Thu Oct 17, 2019 6:17 pm
Forum: *Shrodinger Equation
Topic: Uncertainty Principle Problem
Replies: 3
Views: 18

Uncertainty Principle Problem

What is the minimum uncertainty in the speed of an electron confined within an atom diameter of 3.50 pm?
Is the delta x in the equation the diameter? If so, do I need to change it to meters before I can use the diameter?
by Doreen Liu 4D
Thu Oct 17, 2019 6:13 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Equations
Replies: 3
Views: 27

Photoelectric Effect Equations

The velocity of an electron from a metal surface by a photon is 3.6 x 10^3 km/s. What is the wavelength of ejected e-?
For this question, since wavelength can be calculated by both h/mv and hc/E, how do I determine which one to use?
by Doreen Liu 4D
Thu Oct 17, 2019 6:06 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty Value
Replies: 8
Views: 43

Uncertainty Value

When the uncertainty is some value plus minus another value (e.g. 2.35±0.1 pm), is the uncertainty value 0.1 or is the value altogether the uncertainty?
by Doreen Liu 4D
Thu Oct 10, 2019 9:21 pm
Forum: Einstein Equation
Topic: Energy of photons to Moles
Replies: 2
Views: 55

Energy of photons to Moles

To calculate the energy of one mole of photon, which equation do I use? Can I just multiply the energy of the photon by Avogadro's number?
by Doreen Liu 4D
Thu Oct 10, 2019 9:19 pm
Forum: Properties of Electrons
Topic: work needed
Replies: 2
Views: 39

Re: work needed

The diagram is not a necessity, but it could be useful to visualize what you are working with. You can solve the problem regardless.
by Doreen Liu 4D
Thu Oct 10, 2019 9:17 pm
Forum: Photoelectric Effect
Topic: Work Function
Replies: 4
Views: 60

Re: Work Function

The work function is in the energy of photons equation. It is the threshold energy which is the minimum energy needed to free electrons from a certain metal.
by Doreen Liu 4D
Thu Oct 10, 2019 9:14 pm
Forum: Properties of Light
Topic: Electromagnetic Spectrum
Replies: 5
Views: 51

Re: Electromagnetic Spectrum

I believe the spectrum is something you should know. Just remember that the more dangerous waves like Gamma rays and x-rays are on the high frequency, low wavelength end of the spectrum, while waves like microwaves and radio waves are on the low frequency, high wavelength end of the spectrum.
by Doreen Liu 4D
Thu Oct 10, 2019 9:02 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Intensity of Light
Replies: 7
Views: 52

Photoelectric Effect Intensity of Light

When the experiment changed the intensity of the light on the metal, does that mean the frequency increased? How is intensity measured?
by Doreen Liu 4D
Thu Oct 03, 2019 8:55 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Units in Answer
Replies: 18
Views: 186

Re: Units in Answer

You should always answer with the unit that the question is asking. If it began with moles and asked how many moles are in the end, then keep/convert answer into moles, but if it began with grams and asked for the mass, then keep/convert answer into mass.
by Doreen Liu 4D
Thu Oct 03, 2019 8:51 am
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula Purpose
Replies: 13
Views: 156

Re: Empirical Formula Purpose

The empirical formula shows clearly of all the elements in a certain compound as well as the ratio. However, in Chemistry, the molecular formula is more commonly used rather than empirical formula.
by Doreen Liu 4D
Thu Oct 03, 2019 8:21 am
Forum: Limiting Reactant Calculations
Topic: Homework Question
Replies: 3
Views: 30

Homework Question

Can someone help me with this limiting reactant problem? "Find limiting reagent if 21.4g NH3 is reacted with 42.5g of O2." How do I find the limiting reagent if the ratio is not 1:2?
by Doreen Liu 4D
Wed Oct 02, 2019 9:45 pm
Forum: Significant Figures
Topic: Powers of 10
Replies: 10
Views: 96

Re: Powers of 10

You can write an answer in powers of 10 when it can be easily understood and for sig figs purposes.
by Doreen Liu 4D
Wed Oct 02, 2019 9:22 pm
Forum: Molarity, Solutions, Dilutions
Topic: Unit Conversion for Molarity/Dilution
Replies: 3
Views: 30

Re: Unit Conversion for Molarity/Dilution

When you calculate the molarity, you should convert it to the SI unit L before you calculate so you don't forget to do it at the end.

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