## Search found 20 matches

Thu Dec 07, 2017 3:18 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Diamagnetic VS Paramagnetic [ENDORSED]
Replies: 2
Views: 349

### Re: Diamagnetic VS Paramagnetic[ENDORSED]

Diamagnetic means that all electrons are paired, whereas paramagnetic means there must be at least one unpaired electron in the atom. You can also use "diamagnetic" and "paramagnetic" to describe an individual electron. If the electron is paired, it is diamagnetic, and if it is u...
Thu Dec 07, 2017 3:12 pm
Forum: Ideal Gases
Topic: R constant in PV=nRT
Replies: 2
Views: 334

### Re: R constant in PV=nRT

Yes, the R constant is included in the "constants and equations" sheet that we can use as reference during the final. Here is the full document, also available on the course website.
Sun Dec 03, 2017 3:23 pm
Forum: Ideal Gases
Topic: I deal gas law formula
Replies: 3
Views: 411

### Re: I deal gas law formula

The ideal gas law tells you that pressure and volume are inversely related, while pressure (and volume) are directly related to the number of moles and the temperature.
Sun Dec 03, 2017 3:19 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Sig Figs for Calculating pH and pOH
Replies: 4
Views: 277

### Re: Sig Figs for Calculating pH and pOH

Yes, I believe you are correct about the number of significant figures that the solution should have.
Tue Nov 21, 2017 2:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Difference Between Kp and Kc
Replies: 4
Views: 565

### Re: Difference Between Kp and Kc

If you are confused on knowing when to use which one, you just need to know that you can only use Kp when there is one or more gaseous product or reactant and no aqueous products or reactants.
Tue Nov 21, 2017 2:07 pm
Forum: Ideal Gases
Topic: 11.13
Replies: 2
Views: 212

### Re: 11.13

These reaction quotient expressions always involve products over reactants, but excluding solids and liquids. In a, the products are only solids so the numerator is just 1, while the denominator is the gaseous reactant raised to its coefficient (2) in the chemical reaction. In b, both products are a...
Wed Nov 15, 2017 4:49 pm
Forum: Lewis Structures
Topic: Unrelated midterm question
Replies: 2
Views: 205

### Re: Unrelated midterm question

Yes, near the bottom of Lavelle's website, there's a link that says "Midterm Solutions." It shows the breakdown of points for each question.
Wed Nov 15, 2017 4:46 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Maximum number of ligands
Replies: 3
Views: 245

### Re: Maximum number of ligands

Six is the maximum number of ligands, at least as far as the textbook gets into. This is because the electron pairs repel each other and realistically can't form a bond angle that would be less than 90º
Wed Nov 08, 2017 5:23 pm
Forum: Bond Lengths & Energies
Topic: Homework Problem 3.87
Replies: 5
Views: 403

### Re: Homework Problem 3.87

You know the relative lengths of the bonds because you know the relative electronegativities. F is more electronegative than Cl and Br, and therefore it will bring the electrons as close to it as possible, forming a shorter, stronger bond.
Wed Nov 08, 2017 5:12 pm
Forum: Lewis Structures
Topic: Central Atom? [ENDORSED]
Replies: 7
Views: 644

### Re: Central Atom?[ENDORSED]

The central atom is the one with the lowest ionization energy because having lower ionization energy means being more easily able to share/give up electrons rather than holding on to its lone pairs. An element's first ionization energy is simply the energy required to pull off one electron, so intui...
Wed Nov 01, 2017 4:02 pm
Forum: Trends in The Periodic Table
Topic: 2.71
Replies: 1
Views: 170

### 2.71

In problem 2.71, in discussing the cause of diagonal relationships, the solutions manual says "the lower-right element in the pair would generally be larger because it lies in a higher period, but it also will have a higher oxidation state." Can someone explain what oxidation state means h...
Wed Nov 01, 2017 3:53 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions to the Configuration Rules
Replies: 3
Views: 218

### Re: Exceptions to the Configuration Rules

Copper and chromium are most stable when they have either half filled or fully filled d-orbitals. In the case of chromium, you take away one of the s-orbital electrons so that the element can have a half filled d-orbital ([Ar] 3d5 4s1). With copper, you take away one of the s-orbital electrons so th...
Thu Oct 26, 2017 8:30 pm
Forum: Trends in The Periodic Table
Topic: atomic size
Replies: 4
Views: 273

### Re: atomic size

Generally, the element higher on the periodic table on the left side would have a smaller radius than an element is lower on the periodic table on the right side. This is because moving up and down on the periodic table involves a change in n-levels, which is a more drastic change in energy than jus...
Thu Oct 26, 2017 8:22 pm
Forum: Trends in The Periodic Table
Topic: Exceptions [ENDORSED]
Replies: 4
Views: 349

### Re: Exceptions[ENDORSED]

I believe copper and chromium are the only exceptions that we will need to know for test 3.
Thu Oct 19, 2017 3:34 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Wavelength Units
Replies: 5
Views: 299

### Re: Wavelength Units

Although the final answer may ask for nanometers, when plugging in wavelength to solve for another value, you would always use the meters, as it is the SI unit.
Thu Oct 19, 2017 3:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Magnetic Quantum Number
Replies: 6
Views: 370

### Re: Magnetic Quantum Number

The magnetic quantum number can range from -l to +l. One thing to note, however, is that only integer values are allowed for the magnetic quantum number. For instance, if l=2, the magnetic quantum number could be -2, -1, 0, 1, or 2.
Thu Oct 12, 2017 5:18 pm
Forum: Properties of Light
Topic: the quantum world [ENDORSED]
Replies: 2
Views: 197

### Re: the quantum world[ENDORSED]

We should know how to express wavelength in terms of nanometers as well as meters. With regard to frequency, we need to know the unit of 1 Hertz, equivalent to second^-1. We should also know how to express energy in joules as well as in kilojoules.
Thu Oct 12, 2017 5:03 pm
Forum: Properties of Electrons
Topic: De Broglie Equation
Replies: 3
Views: 1996

### Re: De Broglie Equation

You may also need to use the De Broglie equation if neither wavelength nor frequency are given, but mass and velocity are given. In such a case, you could substitute in (h/mv) for λ in equations like c=λ*frequency.
Thu Oct 05, 2017 4:32 pm
Forum: Molarity, Solutions, Dilutions
Topic: E1
Replies: 1
Views: 217

### Re: E1

Since the question asks about the length of the atoms strung together, we use the diameter instead of the radius. We want the length of across the entire atom, not just half of it. If we were using the 144 instead of 288, we would only be accounting for half of the length that extends the bottom of ...
Thu Oct 05, 2017 4:27 pm
Forum: Molarity, Solutions, Dilutions
Topic: E9 [ENDORSED]
Replies: 5
Views: 1650

### Re: E9[ENDORSED]

After dividing the 5.15 grams of magnesium sulfate heptahydrate by it's molar mass, we get the number of moles of magnesium sulfate heptahydrate present. However, the question asks how many oxygen atoms are present, so we must use the stoichiometric ratio of moles of oxygen per one mole of MgSO4.7H2...

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