Search found 30 matches

by yea-lyn pak_1G
Wed Dec 05, 2018 4:29 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: question 17.33 (sixth edition)
Replies: 1
Views: 15

Re: question 17.33 (sixth edition)

I think the safest bet would be to draw out the lewis structure to make sure that the nitrogen does have two electrons to donate and use for a bond.
by yea-lyn pak_1G
Wed Dec 05, 2018 4:26 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: What exactly is a ligand?
Replies: 2
Views: 19

Re: What exactly is a ligand?

A ligand is whatever ion or molecule is bonded to a metal atom through a coordinate bond. It's basically the electron pair donor. A coordinate bond is a covalent bond (which is when electrons are shared) in which the two electrons were provided by the same atom. Some common ligands are Cl - , Br - ,...
by yea-lyn pak_1G
Wed Dec 05, 2018 4:20 pm
Forum: Naming
Topic: Writing chemical formulas
Replies: 2
Views: 10

Re: Writing chemical formulas

I think it'd only matter - or matter the most - if you were drawing out a structure; then, the order would matter, and it'd be dependent on what is bonding to what. So if another atom was bonding with oxygen, you'd have to make sure that the O is next to that other atom, and that might mean you have...
by yea-lyn pak_1G
Wed Nov 28, 2018 5:40 pm
Forum: Naming
Topic: Naming
Replies: 1
Views: 25

Re: Naming

You find it by looking at its charge. So for that example (with the cobalt) that we did in class, we found that the cobalt has a charge of +2. We know its charge because the total compound is [Co(NH 3 ) 5 ]Cl2H 2 O. The H 2 O and ammonia are neutral, which leaves the two chlorines, which each have a...
by yea-lyn pak_1G
Wed Nov 28, 2018 5:37 pm
Forum: Hybridization
Topic: atomic orbitals
Replies: 2
Views: 25

Re: atomic orbitals

I think you mean region of electron density instead of atomic orbital. If that's the case, then yes a lone pair is counted as a region of electron density.
by yea-lyn pak_1G
Wed Nov 28, 2018 5:35 pm
Forum: Hybridization
Topic: Question 4.31 6th edition
Replies: 1
Views: 12

Re: Question 4.31 6th edition

I think the question wants you to define the hybridization and then explain what kind of shape that would be. So for example, if you had an sp3 hybridization orbital, its orbitals would be oriented towards the corners of a tetrahedron (thus in a tetrahedral shape).
by yea-lyn pak_1G
Sat Nov 24, 2018 11:52 pm
Forum: Octet Exceptions
Topic: list of exceptions and why?
Replies: 1
Views: 25

Re: list of exceptions and why?

I think there are three general cases where exceptions to the octet rule occur. This is a broad overview of them: 1. There are cases where there are an odd number of electrons around an atom/ion. When this occurs, the atom/ion is known as a free radical and these typically don't survive for long bec...
by yea-lyn pak_1G
Sat Nov 24, 2018 11:40 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Polarity and Boiling Point
Replies: 3
Views: 40

Re: Polarity and Boiling Point

Since a higher polarity means the atom/molecule has a stronger negatively charged end and a stronger positively charged end, this leads to greater dipole-dipole interactions between atoms/molecules. Thus, it's harder to pull apart the atoms or molecules and requires a higher boiling point.
by yea-lyn pak_1G
Sat Nov 24, 2018 11:33 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 8
Views: 98

Re: Formal Charge

You can just count the number of dots (each electron in a lone pair) and the number of lines (the number of pairs of electrons). Then subtract the number you counted from the number of valence electrons the atom has.
by yea-lyn pak_1G
Sat Nov 17, 2018 11:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular Structure
Replies: 1
Views: 25

Re: Molecular Structure

H20 only has four regions of electron density, whereas XeF4 has six regions of electron density. So when drawing the VSEPR model for XeF4, you would start out by drawing the fluorines symmetrically about Xe. Then, when you think about the placing of the two lone pairs of electrons, the most stable p...
by yea-lyn pak_1G
Wed Nov 14, 2018 4:52 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm Q4B
Replies: 4
Views: 85

Re: Midterm Q4B

Diffraction is a phenomenon that occurs with waves; diffraction is a result of waves interfering with each other. Thus, the fact that electrons are able to diffract means that they should have wavelike properties. De Broglie's equation basically states that everything has wavelike properties and tha...
by yea-lyn pak_1G
Wed Nov 14, 2018 4:48 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: What to memorize in VSEPR?
Replies: 8
Views: 78

Re: What to memorize in VSEPR?

You're going to need to know the bond angles, too, because this contributes to the overall shape of the structure.
by yea-lyn pak_1G
Wed Nov 14, 2018 4:47 pm
Forum: Resonance Structures
Topic: Formal Charge
Replies: 11
Views: 110

Re: Formal Charge

There are multiple structures that will get you the same, correct overall charge. Thus, you want the structure that has the most 0 formal charges as possible (because this ensures the most stability). If there is a negative formal charge on an atom, it should be on the most electronegative atoms (li...
by yea-lyn pak_1G
Sat Nov 10, 2018 11:57 am
Forum: Lewis Structures
Topic: Molecular shape and structure
Replies: 5
Views: 78

Re: Molecular shape and structure

You would need to do that when drawing a VSEPR, but I think Professor Lavelle also said that when drawing a VSEPR, simply writing/stating what kind of shape the structure is in (ie trigonal planar, linear, etc) will also suffice.
by yea-lyn pak_1G
Sat Nov 10, 2018 11:55 am
Forum: Balancing Chemical Reactions
Topic: Combustion Equation
Replies: 8
Views: 267

Re: Combustion Equation

O2 is always going to be added as a reactant in a combustion equation, and the products will include water and carbon dioxide.
by yea-lyn pak_1G
Sat Nov 10, 2018 11:53 am
Forum: *Shrodinger Equation
Topic: Shrodinger Equation
Replies: 3
Views: 132

Re: Shrodinger Equation

Shrodinger's equation gives the probability of finding an electron at a certain position. Thus, it can be used to explain the shape of orbitals and their orientations.
by yea-lyn pak_1G
Thu Nov 01, 2018 10:05 pm
Forum: Lewis Structures
Topic: central atoms
Replies: 8
Views: 102

Re: central atoms

The atom with the lowest electronegativity is usually in the center. Electronegativity increases as you go up and right through the periodic table.
by yea-lyn pak_1G
Thu Nov 01, 2018 10:02 pm
Forum: Lewis Acids & Bases
Topic: Lewis Acids and Bases on Midterm
Replies: 4
Views: 81

Re: Lewis Acids and Bases on Midterm

I think we do need to know because Professor Lavelle said that everything up to Wednesday's lecture would be on the test, and he did go over lewis acid/base during that lecture. An acid is the compound receiving an electron, whereas a base is the compound donating an electron.
by yea-lyn pak_1G
Thu Nov 01, 2018 9:58 pm
Forum: Ionic & Covalent Bonds
Topic: Copper Ions
Replies: 3
Views: 25

Re: Copper Ions

Their charges are different - Copper(I) has a charge of +1 while Copper(II) has a charge of +2.
by yea-lyn pak_1G
Thu Oct 25, 2018 5:34 pm
Forum: Quantum Numbers and The H-Atom
Topic: 2 Exceptions to the Electron Configuration
Replies: 3
Views: 47

Re: 2 Exceptions to the Electron Configuration

The d orbital gets an extra electron, while the s orbital loses one, and this is so because it just makes the atom more stable.
by yea-lyn pak_1G
Thu Oct 25, 2018 5:26 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Difference in energy between s-, p-, d-, f- orbitals in the same shell
Replies: 2
Views: 79

Re: Difference in energy between s-, p-, d-, f- orbitals in the same shell

I think the reason is because the s-orbital has more shielding; energy level in the s-orbital goes down because it's exposed more to the positive charge, whereas the other orbitals aren't as exposed. I'm not sure how that relates to nodal planes, though.
by yea-lyn pak_1G
Tue Oct 16, 2018 6:41 pm
Forum: Einstein Equation
Topic: Calculating Frequency of Light
Replies: 3
Views: 53

Re: Calculating Frequency of Light

So we make the energy positive because the change in energy of the electron is equal to the energy of the light emitted. When an electron is dropped from a higher energy level to a lower energy level, the electron loses some energy (this is delta E, or change in E). This energy is lost because it's ...
by yea-lyn pak_1G
Tue Oct 16, 2018 5:58 pm
Forum: Photoelectric Effect
Topic: Definition for photoelectric effect
Replies: 4
Views: 35

Re: Definition for photoelectric effect

The photoelectric effect is basically the emission of electrons when light is shone on a surface. In the photoelectric effect experiment, it was found that light waves with low frequency (long wavelength) cannot eject electrons, even with high intensity light.
by yea-lyn pak_1G
Tue Oct 16, 2018 5:51 pm
Forum: Properties of Electrons
Topic: Wave Properties of Electrons
Replies: 3
Views: 62

Re: Wave Properties of Electrons

In the case of an electron moving from an energy level to a higher energy level, like from n=1 to n=3, the electron would absorb light. It absorbs light because it needs energy to jump from a low state to a higher state. In contrast, when moving from a higher energy level to a lower energy level, it...
by yea-lyn pak_1G
Mon Oct 08, 2018 9:39 pm
Forum: General Science Questions
Topic: F9 6th edition
Replies: 1
Views: 67

Re: F9 6th edition

All of your math is right up until after you take the ratio. Rounding to 3 from 2.67 isn't the best way to get a whole number because the general rule for rounding is that the new number should be within 5% of the number you rounded from. Since you have 2.67, 2.67, and 1, the best way to get a whole...
by yea-lyn pak_1G
Mon Oct 08, 2018 9:33 pm
Forum: Empirical & Molecular Formulas
Topic: Determining Empirical and Molecular Formulas
Replies: 2
Views: 116

Re: Determining Empirical and Molecular Formulas

Not a hundred percent sure on this, but I think the general rule is that carbon is first, followed by hydrogen, and everything else remaining is placed alphabetically afterwards. So for example, if you have carbon, nitrogen, hydrogen, and oxygen, it would be: CHNO. I don't know if points are taken o...
by yea-lyn pak_1G
Mon Oct 08, 2018 9:29 pm
Forum: Photoelectric Effect
Topic: Significance of Photoelectric Effect
Replies: 3
Views: 33

Re: Significance of Photoelectric Effect

The initial purpose of the photoelectric effect experiment was to determine how much energy it takes to remove electrons from various metals. Basically, when you shine light onto a metal surface, electrons are given off, and a detector would pick up on those electrons. However, the results of the ex...
by yea-lyn pak_1G
Wed Oct 03, 2018 4:02 pm
Forum: Limiting Reactant Calculations
Topic: finding grams of product
Replies: 2
Views: 36

Re: finding grams of product

Using your example, you would have 0.3 moles of product that can be produced. Then, you'd have to find how many grams of the product is equal to 0.3 moles. So you would have to use the molar mass of the product. So, for example, if you have 0.3 moles of nitrogen produced, you would do (0.3mol)(14g/1...
by yea-lyn pak_1G
Tue Oct 02, 2018 7:17 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula
Replies: 5
Views: 67

Re: Empirical Formula

I think the general rule was that if you're going to round, the rounded number should be within 5% of the original answer you got.
by yea-lyn pak_1G
Tue Oct 02, 2018 7:09 pm
Forum: SI Units, Unit Conversions
Topic: Fundamentals Problem E15
Replies: 4
Views: 89

Re: Fundamentals Problem E15

In this problem, the metal hydroxide is notated as M(OH)2 because we don't know what the metal is; M(OH)2 is basically some metal with the hydroxide (OH). When the problem asks for the molar mass of the sulfide of the metal, it's asking for the molar mass of MS. Basically, the sulfide (S) is replaci...

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