Search found 50 matches

by Ryan Chew 1K
Sat Dec 07, 2019 7:41 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: Test 2, Question 7A
Replies: 3
Views: 42

Re: Test 2, Question 7A

The H bonded to the C atom on the right side of the molecule does not count as a hydrogen bonding site since the electronegativity difference between C and H is not enough for there to be a strong partial positive charge on the hydrogen. H bonding can only occur with F, O, or N atoms.
by Ryan Chew 1K
Sat Dec 07, 2019 7:38 pm
Forum: Lewis Structures
Topic: Lewis for carbon monoxide
Replies: 3
Views: 22

Re: Lewis for carbon monoxide

C and O have a combined total of 10 valence electrons available for bonding. This means that there must be a triple bond with two lone pairs on each atom to satisfy the octet rule, with each atom having 8 electrons. Having only a double bond would means there wouldn't be enough electrons to satisfy ...
by Ryan Chew 1K
Sat Dec 07, 2019 7:34 pm
Forum: Calculating the pH of Salt Solutions
Topic: HW 6D.11
Replies: 1
Views: 28

Re: HW 6D.11

It seems that the Al3+ hybridizes its s, p, and d orbitals to form 6 hybridized orbitals. The reason why it's 6 is because that's the maximum number of H2O molecules that can fit around a Al3+ ion, and by having the maximum number of bonds, it is the most stable. Here is a good resource if you want ...
by Ryan Chew 1K
Sat Dec 07, 2019 7:20 pm
Forum: Naming
Topic: -ate, -ide, -ite, -o
Replies: 3
Views: 28

Re: -ate, -ide, -ite, -o

According to the textbook, for any anion inside the [ ] (so any anion directly bonded to the central metal cation), the ending should be an -ato or an -ido or an -ito. For example, the Chloride anion is written as chlorido. The -ido is part of a newer change, but both the -ido and the -o suffixes a...
by Ryan Chew 1K
Sat Dec 07, 2019 7:19 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strong vs. Weak Acids
Replies: 3
Views: 37

Re: Strong vs. Weak Acids

The structure of oxyacids involves the H atom bonding to the O atom and then to the Cl, I, or whichever atom is remaining. Since the H is not directly bonded to the Cl or I, the bond length is not relevant. Instead, the electronegativity is more important. This is because the Cl or I atom pulls elec...
by Ryan Chew 1K
Sat Dec 07, 2019 7:13 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: Test 2, Question 7A
Replies: 3
Views: 42

Re: Test 2, Question 7A

Yes, you are correct. Each O atom counts as two H bonding sites due to the two lone electron pairs.
by Ryan Chew 1K
Sat Dec 07, 2019 7:09 pm
Forum: Naming
Topic: -ate, -ide, -ite, -o
Replies: 3
Views: 28

Re: -ate, -ide, -ite, -o

The -ate suffix is used for the central metal cation is part a coordination compound that has an overall negative charge (K4[Fe(CN)6] is potassium hexacyanoferrate(II)). The -ide suffix is used for an anion that bonds to the coordination compound (anion that comes after the brackets). The -ite suffi...
by Ryan Chew 1K
Sat Dec 07, 2019 1:32 am
Forum: Naming
Topic: Easy Way to Name/Remember
Replies: 2
Views: 27

Re: Easy Way to Name/Remember

Name the ligands and then the central metal cation in one word. The ligands should be in alphabetical order, ignoring the prefixes, and the central metal cation should be last with its oxidation state. If there is a cation in front of the brackets that bonds to the coordination compound, name the el...
by Ryan Chew 1K
Sat Dec 07, 2019 1:28 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Identifying Acids and Bases
Replies: 2
Views: 25

Re: Identifying Acids and Bases

Yes, if a molecule has a lone pair, it could be used to bond with H+. By donating an electron to the H+, it acts as a Lewis base. For charges, we know that positive transition metal cations act as acids by weakening the bond between H and O in H2O molecules. We also know that negatively charged anio...
by Ryan Chew 1K
Sat Dec 07, 2019 1:24 am
Forum: Conjugate Acids & Bases
Topic: Conjugate base of strong and weak acids
Replies: 1
Views: 25

Re: Conjugate base of strong and weak acids

If we think of it in terms of a reaction and using a chemical equation, it is easier to understand the logic behind this. The dissociation of an acid or base is a reversible reaction. This means that at equilibrium, both the forward and reverse reactions are occurring simultaneously. Let's say that ...
by Ryan Chew 1K
Sat Dec 07, 2019 1:19 am
Forum: Identifying Acidic & Basic Salts
Topic: Weak acid and weak base
Replies: 1
Views: 23

Re: Weak acid and weak base

Since the weak acid and base both do not dissociate very much, the solution will contain mostly the weak acid, weak base, and very small amounts of the salt and its ions. A salt is formed, but the pH is determined by the weak acid and weak base, not the salt.
by Ryan Chew 1K
Sat Dec 07, 2019 1:12 am
Forum: Conjugate Acids & Bases
Topic: 6A.4
Replies: 1
Views: 32

Re: 6A.4

Urea is actually a base, and it reacts with H2O to produce NH3 and CO2. The two H+ come from the H2O and bond to the NH2 groups, and the bonds to the remaining C=O atoms.
by Ryan Chew 1K
Sat Dec 07, 2019 1:06 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6D.11 part d
Replies: 1
Views: 17

Re: 6D.11 part d

In both parts, the K+ cation is a Group 1 element, so we know that it does not affect the pH. The difference is in the anion. The F- anion is the conjugate base of a weak acid (HF), so that means it will lower the pH by acting as a base. For HBr, the Br- anion is the conjugate base of a strong acid ...
by Ryan Chew 1K
Sat Dec 07, 2019 1:03 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6C21
Replies: 2
Views: 31

Re: 6C21

I don't see any H2O components in 6C21. Are you sure you are referring to the correct question? Or do you mean 6D11?
by Ryan Chew 1K
Sat Dec 07, 2019 1:00 am
Forum: Lewis Acids & Bases
Topic: Memorizing Charges of Transition Metals
Replies: 9
Views: 56

Re: Memorizing Charges of Transition Metals

Can't the same metal have different oxidation states, though? Like Fe can be +2 or +3 Yes, but to figure out which oxidation state the metal has, we use the ligands to figure out the charge that we must balance out. As such, memorizing the ligands essentially works towards knowing the oxidation sta...
by Ryan Chew 1K
Sat Dec 07, 2019 12:58 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Ka and Kb
Replies: 3
Views: 29

Re: Ka and Kb

No, I don't think the book goes into detail about bases that accept multiple protons, but it should be the same as polyprotic acids, only in reverse order. The same trends apply.
by Ryan Chew 1K
Sat Dec 07, 2019 12:57 am
Forum: Amphoteric Compounds
Topic: how to identify?
Replies: 5
Views: 70

Re: how to identify?

Yes, amphiprotic compounds fall in the category of amphoteric compounds. All amphiprotic compounds (I don't know about exceptions) are amphoteric, but not all amphoteric compounds are amphiprotic.
by Ryan Chew 1K
Sat Dec 07, 2019 12:55 am
Forum: Calculating the pH of Salt Solutions
Topic: 6D11 E and F
Replies: 1
Views: 39

Re: 6D11 E and F

When the salts are in an aqueous solution, the cation and anion will react differently. In the case of AlCl3, the small, highly positive Al3+ cation will interact with the water molecules and will cause the water molecules to give up a proton, acting as an acid. The Cl- anion is the conjugate base o...
by Ryan Chew 1K
Sat Dec 07, 2019 12:47 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: HW 6C.17.
Replies: 1
Views: 24

Re: HW 6C.17.

The presence of the nitrogen atom usually denotes a weaker base. Furthermore, HBrO is a weak acid, so its conjugate base (BrO-) will be a relatively strong base.
by Ryan Chew 1K
Sat Dec 07, 2019 12:45 am
Forum: Naming
Topic: Naming Anionic Ligands
Replies: 3
Views: 30

Re: Naming Anionic Ligands

I think both are fine, it's just that -ido is part of a newer change, but the old system remains valid still.
by Ryan Chew 1K
Sat Dec 07, 2019 12:43 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid Strength- Acetic vs Formic Acid
Replies: 4
Views: 54

Re: Acid Strength- Acetic vs Formic Acid

The acetic acid has a methyl group attached (CH3), which is an electron-donating compound. As such, the anionic form of the acetic acid is less stable since the CH3 does not delocalize the negative charge and instead adds to it. Meanwhile, the H atom attached to the formic acid is electron-withdrawi...
by Ryan Chew 1K
Wed Dec 04, 2019 10:59 pm
Forum: Lewis Acids & Bases
Topic: Characteristics of Lewis acids
Replies: 2
Views: 27

Re: Characteristics of Lewis acids

What differentiates Bronsted acids from Lewis acids are the definitions of each. However, they are both acids, so they would still share the same properties that acids have, though their strengths may vary.
by Ryan Chew 1K
Wed Dec 04, 2019 10:51 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: Hydrogen bonding
Replies: 1
Views: 24

Re: Hydrogen bonding

A hydrogen bonding site is where there are any lone electron pairs that can experience electrostatic interactions with an atom from another molecule. This is why the O atom in water can form 2 hydrogen bonds with two other hydrogen atoms. For hydrogen bonding to occur, there only needs to be a F, O,...
by Ryan Chew 1K
Wed Dec 04, 2019 10:40 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Ka and Kb
Replies: 3
Views: 29

Re: Ka and Kb

Yes I would assume so since polyprotic bases and Kb values act similar to acids other than accepting protons. Although it is in reverse, polyprotic bases would accept protons less and less readily the more protons they gain.
by Ryan Chew 1K
Wed Dec 04, 2019 10:33 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Resonance and Acid strength
Replies: 1
Views: 18

Re: Resonance and Acid strength

Resonance stabilizes the products of acid dissociation reactions by delocalizing the negative charge so it is spread out more evenly among all the atoms. Since the product is more stable, the equilibrium is shifted to the right, leading to a stronger acid since it will more readily dissociate.
by Ryan Chew 1K
Wed Dec 04, 2019 10:31 pm
Forum: Lewis Acids & Bases
Topic: Memorizing Charges of Transition Metals
Replies: 9
Views: 56

Re: Memorizing Charges of Transition Metals

Can't the same metal have different oxidation states, though? Like Fe can be +2 or +3 Yes, but to figure out which oxidation state the metal has, we use the ligands to figure out the charge that we must balance out. As such, memorizing the ligands essentially works towards knowing the oxidation sta...
by Ryan Chew 1K
Wed Dec 04, 2019 10:27 pm
Forum: Identifying Acidic & Basic Salts
Topic: amphoteric versus amphiprotic
Replies: 1
Views: 15

Re: amphoteric versus amphiprotic

Amphiprotic substances can donate or accept H+. This means they are also amphoteric since they can act as either an acid or a base. However, amphoteric substances make up a broader category than amphiprotic substances. This is because there are different definitions of acids and bases (Lewis, Bronst...
by Ryan Chew 1K
Wed Dec 04, 2019 10:22 pm
Forum: Naming
Topic: Cation Order
Replies: 1
Views: 15

Re: Cation Order

I believe writing the cations and anions in the order they are named/written is fine. So pentaamminechloroplatinum(IV) bromide would be [Pt(NH3)5Cl]Br3. Alphabetical order is very important when naming the compounds. Otherwise, the order is not essential as long as the general arrangement is correct.
by Ryan Chew 1K
Wed Dec 04, 2019 10:14 pm
Forum: Naming
Topic: Ligands
Replies: 2
Views: 16

Re: Ligands

Yes, I believe my TA mentioned something about naming ligands likely being on the final, so it would be best to memorize the chart.
by Ryan Chew 1K
Wed Dec 04, 2019 10:13 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: How do you tell if parts of a molecule are in the same plane?
Replies: 2
Views: 17

Re: How do you tell if parts of a molecule are in the same plane?

It mostly depends on the shape. I found looking at Google images of 3D representations of VSEPR theory shapes helped a lot. https://tse4.mm.bing.net/th?id=OIP.EZWgs8att7jBKyzxvarQ_gHaEC&pid=Api For example, in a seesaw-shaped molecule, there are two different planes that the atoms are in. The tw...
by Ryan Chew 1K
Tue Dec 03, 2019 1:16 am
Forum: Bronsted Acids & Bases
Topic: Relative Acid Strength
Replies: 1
Views: 29

Re: Relative Acid Strength

The methyl group is electron releasing group, meaning that it is more likely to donate an electron. This is because the carbon is slightly more electronegative than the hydrogen, and its partial negative charge repulses its remaining electron. Since it is more likely to donate an electron compared t...
by Ryan Chew 1K
Tue Dec 03, 2019 1:01 am
Forum: Lewis Acids & Bases
Topic: Memorizing Charges of Transition Metals
Replies: 9
Views: 56

Re: Memorizing Charges of Transition Metals

Yes, I think it is best to memorize the charges of the transition metals, especially since nitrite is relatively simple to memorize.
by Ryan Chew 1K
Tue Dec 03, 2019 12:58 am
Forum: Naming
Topic: Mono for Ligands with only one
Replies: 1
Views: 18

Re: Mono for Ligands with only one

I don't think it is necessary, seeing as how the homework and lecture omit the mono prefix. It seems like it would be too redundant especially with the length of some ligand names.
by Ryan Chew 1K
Mon Dec 02, 2019 11:29 pm
Forum: Amphoteric Compounds
Topic: how to identify?
Replies: 5
Views: 70

Re: how to identify?

Compounds containing multiple hydrogen atoms are amphoteric since they can donate and accept hydrogens. For compounds that don't contain multiple hydrogens, we know that certain elements form amphoteric compounds. These elements include copper, zinc, tin, lead, aluminium, and beryllium, and they for...
by Ryan Chew 1K
Mon Dec 02, 2019 11:19 pm
Forum: Naming
Topic: Table 9C.1
Replies: 6
Views: 49

Re: Table 9C.1

I think to be safe, I would memorize them, especially since they are used in the homework problems. However, I would ask a TA or professor about this.
by Ryan Chew 1K
Mon Nov 18, 2019 10:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Exact Bond Angles for Test 1
Replies: 3
Views: 34

Exact Bond Angles for Test 1

Do we need to know the exact bond angles for molecular shapes that have lone electron pairs or can we just say slightly less than 109.5 degrees for AX3E and AX2E2 (NH3 and H2O)?
by Ryan Chew 1K
Sun Oct 20, 2019 10:56 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Sequence of Orbitals in a Singl
Replies: 3
Views: 19

Re: Sequence of Orbitals in a Singl

I believe that Dr. Lavelle said that it is random/arbitrary since px, py, and pz can all be generalized to the p subshell.
by Ryan Chew 1K
Sun Oct 20, 2019 10:53 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal Planes
Replies: 3
Views: 37

Re: Nodal Planes

Nodal planes can tell us the properties of atoms in how they can interact with each other. Since atoms can form bonds with each other through their electrons, nodal planes are important since they are essentially regions where no electrons can be found. As such, this is related to orbitals since som...
by Ryan Chew 1K
Sun Oct 20, 2019 10:49 pm
Forum: *Shrodinger Equation
Topic: Schrodinger's Equation
Replies: 2
Views: 22

Re: Schrodinger's Equation

Image
by Ryan Chew 1K
Sun Oct 20, 2019 10:45 pm
Forum: Properties of Electrons
Topic: What's the difference between a shell, a subshell, an energy level, and an orbital?
Replies: 8
Views: 60

Re: What's the difference between a shell, a subshell, an energy level, and an orbital?

The three quantum numbers (n, l, and ml) describe an orbital, which is the math function used to describe an electron's probable position. The principle quantum number (n) refers to the overall energy and size of the orbital. An energy shell and energy level are interchangeable terms. The angular mo...
by Ryan Chew 1K
Sun Oct 20, 2019 10:32 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Spin
Replies: 2
Views: 14

Re: Electron Spin

The arrows are different directions to indicate the opposite electron spins. Although the electrons aren't actually spinning up and down, we can indicate their spins with up and down arrows. As to why we write the up arrow before the down arrow, I believe it is arbitrary seeing as how the direction ...
by Ryan Chew 1K
Sun Oct 13, 2019 2:07 pm
Forum: Properties of Light
Topic: Problem 1.31
Replies: 1
Views: 28

Re: Problem 1.31

To solve this, we must calculate the energy of the photons of each laser. First, we start with the high-intensity red ruby laser and calculate the frequency. c = \lambda v 3.00 \times 10^{8} m/s = (694 \times 10^{-9} m)(v) v = 4.32 \times 10^{14} Hz Then, we substitute the frequency ...
by Ryan Chew 1K
Sun Oct 13, 2019 1:32 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Self-test 1B.4B
Replies: 2
Views: 25

Re: Self-test 1B.4B

For this, you would use the DeBroglie Equation to calculate the wavelength of a moving object with momentum.



by Ryan Chew 1K
Sat Oct 12, 2019 7:54 pm
Forum: Properties of Light
Topic: Equations We’ve Learned So Far
Replies: 11
Views: 97

Re: Equations We’ve Learned So Far

Is there a specific example or equation you're having trouble with? I'm not sure if I can describe all of them.
by Ryan Chew 1K
Sat Oct 12, 2019 7:51 pm
Forum: Properties of Light
Topic: Absorption Spectra
Replies: 1
Views: 35

Re: Absorption Spectra

In absorption spectroscopy, light excites the electrons of a gas, causing them to jump to higher energy levels. The electrons are not as stable at higher energy levels, so they drop back down to their original energy level, releasing the energy in the form of light. Depending on the element, the abs...
by Ryan Chew 1K
Sun Oct 06, 2019 10:03 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic vs Covalent
Replies: 29
Views: 371

Re: Ionic vs Covalent

covalent network are the strongest (ex. diamond and graphite) are stronger than ionic however covalent bonds themselves are usually weaker than ionic bonds. How much of knowledge like this will be required for the final in this class? Right now, we haven't gotten to covalent networks, but in genera...
by Ryan Chew 1K
Fri Oct 04, 2019 12:26 pm
Forum: Properties of Light
Topic: Amplitude? [ENDORSED]
Replies: 8
Views: 84

Re: Amplitude? [ENDORSED]

Does that mean that a higher amplitude corresponds to a higher intensity of light?
by Ryan Chew 1K
Fri Oct 04, 2019 12:24 pm
Forum: Properties of Light
Topic: CHEM 1A
Replies: 2
Views: 38

Re: CHEM 1A

When electrons transition from higher energy levels to lower energy levels, they go from a state of higher energy to a state of lower energy. During this process, energy is released in the form of light.
by Ryan Chew 1K
Wed Oct 02, 2019 12:16 am
Forum: Empirical & Molecular Formulas
Topic: Clarification on the Vitamin C Example
Replies: 6
Views: 71

Re: Clarification on the Vitamin C Example

Elaborating on the rounding aspect, all the numbers provided have three significant figures. Since one of the numbers is less than 1, it makes sense for there to be some small mass lost in the calculations as the other numbers would be rounded.
by Ryan Chew 1K
Wed Oct 02, 2019 12:01 am
Forum: Significant Figures
Topic: General Rules to Help with Sig Figs
Replies: 18
Views: 188

Re: General Rules to Help with Sig Figs

I understand how to keep track of sig figs after calculations, but I'm not sure when I should use them. Do I round between each calculation or at the very end for the final answer? If at the very end, how do we know how many sig figs to use?

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