Search found 51 matches

by Cynthia Gong 1L
Tue Dec 03, 2019 10:46 am
Forum: Amphoteric Compounds
Topic: Amphoteric/acidic/basic
Replies: 5
Views: 48

Re: Amphoteric/acidic/basic

Usually you would use the periodic table for this. Metals form basic oxides while nonmetals form acidic oxides. metalloids tend to form amphoteric oxides
by Cynthia Gong 1L
Tue Dec 03, 2019 10:42 am
Forum: Amphoteric Compounds
Topic: water
Replies: 4
Views: 28

Re: water

In a basic solution water will form OH- while in an acidic solution water accepts an H+ and forms a hydronium ion H3O+
by Cynthia Gong 1L
Tue Dec 03, 2019 10:40 am
Forum: Air Pollution & Acid Rain
Topic: Reducing Acid Rain
Replies: 4
Views: 339

Re: Reducing Acid Rain

Decrease energy consumption, use renewable sources, burn clean coal
by Cynthia Gong 1L
Tue Dec 03, 2019 10:38 am
Forum: Conjugate Acids & Bases
Topic: Question on Problem 6.21
Replies: 1
Views: 67

Re: Question on Problem 6.21

This is because oxygen is more electronegative and less likely to share its electrons with a proton
by Cynthia Gong 1L
Tue Dec 03, 2019 10:33 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strength of Strong Acids
Replies: 2
Views: 27

Re: Strength of Strong Acids

the strength of an acid can be ranked by the extent to which they ionize in an aqueous solution. Strong acids completely ionize, while weak acids only partially ionize
by Cynthia Gong 1L
Mon Nov 25, 2019 5:39 pm
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Alkali Metals and Alkaline Earth Metals
Replies: 2
Views: 172

Re: Alkali Metals and Alkaline Earth Metals

They are also strong because they completely dissociate in water
by Cynthia Gong 1L
Mon Nov 25, 2019 5:37 pm
Forum: Bronsted Acids & Bases
Topic: J.9C and ionic equations
Replies: 1
Views: 43

Re: J.9C and ionic equations

For complete ionic equations, write the balanced equation but with all strong electrolytes written as dissociated ions.
by Cynthia Gong 1L
Mon Nov 25, 2019 5:36 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: chemical equation states
Replies: 2
Views: 35

Re: chemical equation states

Acids are all aqueous because they must be able to dissociate in water. You are correct that when water is added, both products are aqueous as well.
by Cynthia Gong 1L
Mon Nov 25, 2019 5:34 pm
Forum: Biological Examples
Topic: Coordination Compounds
Replies: 2
Views: 36

Re: Coordination Compounds

I believe there was a chart Dr. Lavelle had sent out
by Cynthia Gong 1L
Mon Nov 25, 2019 5:31 pm
Forum: Naming
Topic: roman numerals
Replies: 7
Views: 55

Re: roman numerals

I believe the II refers to the +2 charge of the nickel in the compound.
by Cynthia Gong 1L
Mon Nov 18, 2019 10:22 pm
Forum: Dipole Moments
Topic: Determining state based on intermolecular interactions
Replies: 1
Views: 36

Re: Determining state based on intermolecular interactions

There is no specific interaction that would guarantee liquid state at room temperature, but a general guideline would be that gases have the weakest intermolecular interactions at room temperature (London Dispersion), liquids have interactions with strengths somewhere in between, and solids have the...
by Cynthia Gong 1L
Mon Nov 18, 2019 10:19 pm
Forum: Sigma & Pi Bonds
Topic: HW 2F.3
Replies: 2
Views: 35

Re: HW 2F.3

I think that's because the textbook used the resonance structure where there is one single-bonded O and one double-bonded O, and so as a result there is only one pi bond.
by Cynthia Gong 1L
Mon Nov 18, 2019 10:15 pm
Forum: Ionic & Covalent Bonds
Topic: Study Group
Replies: 8
Views: 104

Re: Study Group

I'm interested in joining this group too! Where do you guys meet?
by Cynthia Gong 1L
Mon Nov 18, 2019 10:14 pm
Forum: Ionic & Covalent Bonds
Topic: Is ionic or covalent stronger?
Replies: 4
Views: 65

Re: Is ionic or covalent stronger?

ionic bonds are stronger because the molecules will form a tightly knit crystal lattice structure that is extremely strong.
by Cynthia Gong 1L
Mon Nov 18, 2019 10:13 pm
Forum: Ionic & Covalent Bonds
Topic: HS vs HO
Replies: 4
Views: 42

Re: HS vs HO

The intramolecular bond between HO would be stronger than the intramolecular bond between HS because of the stronger effective nuclear charge present in the nucleus of O. As a result, HO is more tightly bound.
by Cynthia Gong 1L
Wed Nov 13, 2019 11:37 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: Covalent bonding
Replies: 5
Views: 38

Re: Covalent bonding

On the other hand, intramolecular forces such as covalent bonding occur between the individual atoms in a molecule.
by Cynthia Gong 1L
Wed Nov 13, 2019 11:32 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: intermolecular forces
Replies: 8
Views: 63

Re: intermolecular forces

An overall molecule has a dipole if there is a great difference in electronegativity between the individual atoms that compose that molecule.
by Cynthia Gong 1L
Wed Nov 13, 2019 11:31 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Intermolecular Forces
Replies: 2
Views: 21

Re: Intermolecular Forces

To determine the type of intermolecular force present, you look at the the difference in electronegativity between the atoms in a molecule. If the there is a great difference in electronegativity, a dipole-dipole interaction will occur with other polarized molecules or a dipole-induced dipole intera...
by Cynthia Gong 1L
Wed Nov 13, 2019 11:28 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Single/Double Bonds in Resonance
Replies: 6
Views: 55

Re: Single/Double Bonds in Resonance

Single, double ,and triple bonds are all considered one region of electron density in the VSEPR model. So regardless of resonance structures, the shape of the VSEPR model won't be affected.
by Cynthia Gong 1L
Wed Nov 06, 2019 11:03 pm
Forum: Dipole Moments
Topic: Dipole moments
Replies: 5
Views: 50

Re: Dipole moments

^^ Building upon what they said, dipole moments occur because electrons are pulled towards the more electronegative side of the bond, so one side becomes more negatively charged while the other side becomes more positively charged
by Cynthia Gong 1L
Wed Nov 06, 2019 10:59 pm
Forum: Bond Lengths & Energies
Topic: Midterm
Replies: 9
Views: 113

Re: Midterm

^^ Yep, he said he would try his best to get it done in a week.
by Cynthia Gong 1L
Wed Nov 06, 2019 10:58 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: smaller cations
Replies: 3
Views: 33

Re: smaller cations

Cation radii follows the normal atomic radii trend. It increases across a period and decreases down a group. This is because moving across, the number of protons increases, thus increasing effective nuclear charge and decreases the size. If we have 3 cations that are isoelectronic, for instance: Na+...
by Cynthia Gong 1L
Wed Nov 06, 2019 10:53 pm
Forum: Resonance Structures
Topic: Formal Charge Question
Replies: 15
Views: 142

Re: Formal Charge Question

The most stable and ideal resonance structure would have a formal charge of 0 on each individual atom. However, that may not happen if the molecule is charged. If we have something such as SO4(2-), then the individual formal charges on each individual atom should add up to a total of -2. If a resona...
by Cynthia Gong 1L
Wed Nov 06, 2019 10:48 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Central atom: formal charge v electronegativity
Replies: 3
Views: 31

Re: Central atom: formal charge v electronegativity

The least electronegative atom goes in the center since it is less likely to interact with the electrons in surrounding molecules. The more electronegative atoms typically go on the outside. It is ideal if all the formal charges are 0, but if that is not possible then negative formal charges should ...
by Cynthia Gong 1L
Tue Oct 29, 2019 12:17 pm
Forum: Dipole Moments
Topic: Atom Shapes
Replies: 2
Views: 23

Re: Atom Shapes

Yep! It's going to be covered in the next unit and will be included in the final, but will not be part of our midterm.
by Cynthia Gong 1L
Tue Oct 29, 2019 12:16 pm
Forum: Ionic & Covalent Bonds
Topic: When is the midterm?
Replies: 5
Views: 54

Re: When is the midterm?

The locations should be reposted again by the next class session, if not he will most likely email them to us.
by Cynthia Gong 1L
Tue Oct 29, 2019 12:13 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm
Replies: 10
Views: 108

Re: Midterm

I don't believe locations for the midterm have been released yet.
by Cynthia Gong 1L
Tue Oct 29, 2019 12:08 pm
Forum: Bond Lengths & Energies
Topic: bond lengths
Replies: 10
Views: 96

Re: bond lengths

Double and Triple bonds have more electrons, so they exert a stronger attractive force on the nuclei of the other atom, thus pulling the two atoms close together and reducing the bond length.
by Cynthia Gong 1L
Tue Oct 29, 2019 12:05 pm
Forum: Ionic & Covalent Bonds
Topic: Polar vs Nonpolar bond strength
Replies: 2
Views: 17

Re: Polar vs Nonpolar bond strength

Polarity definitely affects the bond strength. When you are talking about intermolecular bonds, polar bonds will always be stronger than non-polar bonds because polar bonds have dipole-dipole attraction, which are much stronger than the London Dispersion Forces that are only present in non-polar bon...
by Cynthia Gong 1L
Tue Oct 22, 2019 10:35 pm
Forum: Trends in The Periodic Table
Topic: Periodic Trend Exceptions
Replies: 7
Views: 63

Re: Periodic Trend Exceptions

Another exception is electron affinity for noble gases. Electron affinity increases across a period until you get to a noble gas, because when an electron is added to the full shell of a noble gas, the stability of the atom becomes destroyed.
by Cynthia Gong 1L
Tue Oct 22, 2019 10:32 pm
Forum: Trends in The Periodic Table
Topic: Ionic Radius
Replies: 4
Views: 39

Re: Ionic Radius

This is also because anions have more electrons, so there is more electron-electron repulsion present that causes the radius to be bigger.
by Cynthia Gong 1L
Tue Oct 22, 2019 4:29 pm
Forum: *Particle in a Box
Topic: Midterm
Replies: 17
Views: 1322

Re: Midterm

You can go into the SAC's test bank and see if they have Lavelle's old midterm
by Cynthia Gong 1L
Tue Oct 22, 2019 4:24 pm
Forum: DeBroglie Equation
Topic: Velocity
Replies: 13
Views: 192

Re: Velocity

For tests I believe everything will be in SI units. If not, we will get the conversion factors
by Cynthia Gong 1L
Tue Oct 22, 2019 4:16 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy for the 2nd Electron
Replies: 3
Views: 22

Re: Ionization Energy for the 2nd Electron

Conceptually, the 2nd ionization energy is higher than the first because there is less electron-electron repulsion present in the atom, which results in the remaining electrons being "held" onto tighter. Similarly, the 3rd ionization energy will always be higher than the 2nd, and so on.
by Cynthia Gong 1L
Tue Oct 22, 2019 4:11 pm
Forum: Trends in The Periodic Table
Topic: Hw Help 1F.22
Replies: 2
Views: 20

Re: Hw Help 1F.22

I believe there are color-coded periodic tables available that tell you what each type of element is:
ex. https://www.chemicalsafetyfacts.org/wp- ... d-650w.jpg
by Cynthia Gong 1L
Wed Oct 16, 2019 4:18 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Energy levels
Replies: 3
Views: 33

Re: Energy levels

The 4d orbital does have a higher energy level than the 5s orbital. Higher principal quantum numbers aren't necessarily always associated with higher energy levels, such as this case of 4d vs. 5s.
by Cynthia Gong 1L
Wed Oct 16, 2019 4:09 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Atomic Radius
Replies: 18
Views: 137

Re: Atomic Radius

The atomic radius is half the distance between the nuclei of two identical atoms bonded together. For the purpose of this class I don't think we would be calculating the exact value of the radius.
by Cynthia Gong 1L
Wed Oct 16, 2019 4:06 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Electron spin
Replies: 8
Views: 99

Re: Electron spin

I believe +1/2 and -1/2 are the only possible spin states
by Cynthia Gong 1L
Wed Oct 16, 2019 3:47 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Difference Between Ground and Excited States
Replies: 3
Views: 28

Difference Between Ground and Excited States

Can someone summarize how to tell whether an atom is in the ground state or excited state?
by Cynthia Gong 1L
Tue Oct 15, 2019 2:14 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Time of Use
Replies: 5
Views: 41

Re: Time of Use

The question will most likely ask you to calculate the uncertainty of momentum or the uncertainty in position
by Cynthia Gong 1L
Thu Oct 10, 2019 7:15 pm
Forum: SI Units, Unit Conversions
Topic: Problem E27
Replies: 1
Views: 70

Re: Problem E27

a) you know that the molar mass of water is ~18g, and that one mole of water contains 6.022 x 10^23 water molecules. To find the mass per molecule, simply divide the total molar mass by the number of water molecules b) molar mass of water is 18g, to find number of moles in 1kg divide 1kg (1000g) by ...
by Cynthia Gong 1L
Thu Oct 10, 2019 5:27 pm
Forum: Properties of Light
Topic: Energy Levels
Replies: 8
Views: 123

Energy Levels

Can someone pls explain why n=1 is the ultraviolet region, but when an electron drops down from a higher level, it loses energy? I was under the assumption that waves in the ultraviolet region have higher energy.
by Cynthia Gong 1L
Thu Oct 10, 2019 5:15 pm
Forum: Empirical & Molecular Formulas
Topic: Homework F9
Replies: 4
Views: 63

Re: Homework F9

^^ The technique above is what I was taught -- basically think of all of the decimals as fractions where you have to get rid of the denominator
by Cynthia Gong 1L
Thu Oct 10, 2019 5:11 pm
Forum: Limiting Reactant Calculations
Topic: L 35 Textbook Typo [ENDORSED]
Replies: 4
Views: 101

Re: L 35 Textbook Typo [ENDORSED]

@ ATingin_3I the t would stand for ton, and 1 ton equates to 1000kg
by Cynthia Gong 1L
Tue Oct 08, 2019 2:06 pm
Forum: Limiting Reactant Calculations
Topic: Test 1
Replies: 11
Views: 178

Re: Test 1

I think it will be sufficient if you do all the recommended problems since that gives you a good overview of all the different types of problem situations.
by Cynthia Gong 1L
Wed Oct 02, 2019 6:26 pm
Forum: Limiting Reactant Calculations
Topic: Limiting reactant
Replies: 4
Views: 23

Re: Limiting reactant

The limiting reactant should be the one that produces the fewest number of moles of product. That can be figured out by comparing mole ratios between that reactant and the product.
by Cynthia Gong 1L
Wed Oct 02, 2019 2:32 pm
Forum: Limiting Reactant Calculations
Topic: HW M19
Replies: 2
Views: 33

Re: HW M19

For all combustion problems, you would use molar ratios to solve for the empirical formula. For instance, in this problem you are given that there is 0.682 g of CO2 produced. The molecular weight of CO2 is around 44g, so you divide 0.682/44 to calculate the number of moles of CO2 that is produced in...
by Cynthia Gong 1L
Wed Oct 02, 2019 2:21 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Molar mass vs. Molecular Weight
Replies: 5
Views: 82

Re: Molar mass vs. Molecular Weight

^^ That is correct! We can use water as an example. For instance, water is made of hydrogen and oxygen. Hydrogen has a molar mass of 1.0079g while oxygen has a molar mass of 15.999. The values of molar mass are found from the periodic table. Meanwhile, water is a molecule made up of oxygen and hydro...
by Cynthia Gong 1L
Wed Oct 02, 2019 8:37 am
Forum: Student Social/Study Group
Topic: Study Group Fall 2019
Replies: 32
Views: 1568

Re: Study Group Fall 2019

I'm also interested! Hopefully we can get a few more people
by Cynthia Gong 1L
Tue Oct 01, 2019 11:34 am
Forum: Significant Figures
Topic: Determining how many sig figs to use
Replies: 3
Views: 63

Re: Determining how many sig figs to use

Typically your answer would contain the least amount of sig figs that is present in the question. Since in the example the number 2.1 has the least amount of sig figs of 2, your solution would contain 2 sig figs. As a result I believe your decimal answer would be rounded to 5.0. Hopefully someone el...

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