## Search found 34 matches

Tue Jun 12, 2018 12:20 am
Forum: Lewis Acids & Bases
Topic: BaO [ENDORSED]
Replies: 1
Views: 257

### BaO[ENDORSED]

What makes BaO basic?
Sun Jun 10, 2018 11:43 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 12.49
Replies: 3
Views: 297

### Re: 12.49

Yes, we will be given the values.
Sun Jun 10, 2018 11:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent/angular [ENDORSED]
Replies: 5
Views: 338

### Re: Bent/angular[ENDORSED]

I believe angular is the same thing as bent.
Sun Jun 10, 2018 11:38 pm
Forum: Polyprotic Acids & Bases
Topic: ligand bonds
Replies: 2
Views: 446

### Re: ligand bonds

When written this way, the first atom is the element that is bonded to the central metal. The other two after that are bonded to that first atom.
Sun Jun 10, 2018 11:35 pm
Forum: Hybridization
Topic: pi bonds and sigma bonds [ENDORSED]
Replies: 4
Views: 430

### Re: pi bonds and sigma bonds[ENDORSED]

All bonds have one sigma bond. Double bonds have one sigma bond and one pi bond. Triple bonds have one sigma bond and 2 pi bonds.
Sun Jun 10, 2018 11:34 pm
Forum: Lewis Acids & Bases
Topic: pH
Replies: 3
Views: 367

### Re: pH

I think we just need to know if they are considered basic or acidic, but not the exact pH.
Thu Jun 07, 2018 3:55 pm
Forum: Bronsted Acids & Bases
Topic: Do we need to memorize table 12.2 and 12.3? [ENDORSED]
Replies: 3
Views: 399

### Re: Do we need to memorize table 12.2 and 12.3?[ENDORSED]

We do not need to memorize these.
Sun Jun 03, 2018 3:20 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR formula with 2 central atoms
Replies: 2
Views: 231

### VSEPR formula with 2 central atoms

How do you determine the VSEPR formula with 2 central atoms? For example, in 4.21 D how would you find the VSEPR formula for N2H4?
Sun May 27, 2018 5:46 pm
Forum: Lewis Structures
Topic: Single electron
Replies: 5
Views: 227

### Re: Single electron

Sun May 27, 2018 5:37 pm
Forum: Octet Exceptions
Topic: 3.61
Replies: 4
Views: 1578

### Re: 3.61

ICl4-1 has 36 valence electrons, but if you fill up all the octets there are still 4 left over. I is an exception to the octet rule so you can add lone pairs to it.
Sat May 26, 2018 10:27 am
Forum: Resonance Structures
Topic: ranking
Replies: 11
Views: 808

### Re: ranking

If they have the same formal charge overall, choose the one with the smallest individual formal charges. For example, if one of them has -2 and 2, so the formal charge is 0, and the other has all 0's, the one with all 0's is ranked higher.
Sun May 20, 2018 9:39 pm
Forum: Bond Lengths & Energies
Topic: Test 3
Replies: 8
Views: 417

### Re: Test 3

Yes, we have to draw lewis structures for test 3.
Sun May 20, 2018 4:27 pm
Forum: Lewis Structures
Topic: When to use lone pairs or bonds
Replies: 2
Views: 185

### When to use lone pairs or bonds

When drawing lewis structures with a central atom that is an exception to the octet rule, how do you know whether to add a double bond or an extra lone pair onto the central atom?
Fri May 18, 2018 9:22 pm
Forum: Formal Charge and Oxidation Numbers
Topic: 3.53
Replies: 4
Views: 487

### Re: 3.53

Yes. The overall formal charge for all of them are zero, so you have to look at the formal charges for each individual atom. Then choose the one that has formal charges closest to zero because that one is the most stable.
Mon May 14, 2018 1:24 pm
Forum: Lewis Structures
Topic: Homework 3.39
Replies: 1
Views: 152

### Homework 3.39

Write the complete Lewis structure for each of the following compounds: (a) ammonium chloride
I understand how to get the Lewis structure from the chemical formula, but I do not understand how to get the chemical formula of ammonium chloride.
Sun May 13, 2018 4:12 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy vs. Electron Affinity
Replies: 4
Views: 242

### Re: Ionization Energy vs. Electron Affinity

However, although ionization energy and electron affinity are different things, they both follow the same periodic table trends.
Sun May 13, 2018 4:08 pm
Forum: Lewis Structures
Topic: BrO- Lewis Structure
Replies: 2
Views: 783

### Re: BrO- Lewis Structure

Br has 7 valence electrons and O has 6. 7+6=13, add 1 because of the (-) so your total is 14 valence electrons. Br and O share a pair of electrons, so there are 2 dots between Br and O. then there are 2 more dots on each side of Br and O so that the total is 14 dots. Then you put brackets around the...
Sun May 13, 2018 4:02 pm
Forum: Lewis Structures
Topic: monatomic ion
Replies: 2
Views: 162

### monatomic ion

What is a monatomic ion as in question 3.25?
Sun May 06, 2018 11:08 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: midterm Q.7b [ENDORSED]
Replies: 3
Views: 247

### Re: midterm Q.7b[ENDORSED]

I think E infinity = 0 is meant to show that the highest energy level is 0, and as you approach n=1 you keep releasing energy, and if you are releasing energy from a value of 0 it must be negative.
Sun May 06, 2018 11:02 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: How many significant figures? [ENDORSED]
Replies: 5
Views: 263

### How many significant figures?[ENDORSED]

On one of the UA's practice tests (Lyndon's), question 7a asked "An excited hydrogen atom undergoes an electronic transition from n=3 to n=1. Calculate the frequency of the photon emitted." Since the question only contains numbers with 1 significant figure, should we answer with only one?
Sun May 06, 2018 10:43 pm
Forum: SI Units, Unit Conversions
Topic: #9 on Midterm Practice Review (unicorn)
Replies: 4
Views: 404

### Re: #9 on Midterm Practice Review (unicorn)

It doesn't matter if you convert mL to L before you solve the problem or after you solve it, as long as you use the same unit the whole time you are solving the problem. Answers are usually given in L, but the UA gave the answer in mL.
Sun Apr 29, 2018 9:09 pm
Forum: Quantum Numbers and The H-Atom
Topic: Nodal Planes- what are they exactly? [ENDORSED]
Replies: 6
Views: 11937

### Re: Nodal Planes- what are they exactly?[ENDORSED]

A nodal plane is a plane where the probability of finding an electron is zero.
Sun Apr 29, 2018 8:46 pm
Forum: DeBroglie Equation
Topic: Module Question [ENDORSED]
Replies: 3
Views: 334

### Re: Module Question[ENDORSED]

QuincyH1G wrote:whats the opposite?

The opposite, when the peak of one wave corresponds with the peak of another or when the trough of one wave corresponds with another, is called constructive interference.
Sun Apr 29, 2018 8:40 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Lyman Series
Replies: 4
Views: 204

### Re: Lyman Series

UV light is used in the Lyman series.
Mon Apr 23, 2018 12:18 am
Forum: Einstein Equation
Topic: finding frequency from Einstein's equation [ENDORSED]
Replies: 3
Views: 324

### Re: finding frequency from Einstein's equation[ENDORSED]

λ = h/p
since p is given and h is a constant, you can solve for λ with that equation. Then you can solve for frequency using λc=v because you know λ and c is a constant.
Mon Apr 23, 2018 12:12 am
Forum: Properties of Light
Topic: Wave and Particle
Replies: 10
Views: 718

### Re: Wave and Particle

Someone said this in another answer and I thought it was really helpful:
"An individual light particle is called a "photon." The flow of photons moves in a wave and have wave characteristics light wavelength and frequency."
Mon Apr 23, 2018 12:09 am
Forum: Properties of Light
Topic: Test 2 Material
Replies: 12
Views: 706

### Re: Test 2 Material

My TA said that there will be no material from test 1 repeated on test 2.
Sun Apr 15, 2018 9:28 pm
Forum: Photoelectric Effect
Topic: Example 1.5 c
Replies: 3
Views: 171

### Example 1.5 c

In example 1.5 in the textbook part c, we are told to set Ek to 0 to find the longest wavelength or radiation that is able to eject an electron, so hv=phi. They then concluded that lambda=ch/phi. How did they get to this conclusion?
Thu Apr 12, 2018 12:37 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant
Replies: 9
Views: 2420

### Re: Limiting Reactant

Once you calculate the moles of each reactant you have, given that the problem gave you two masses to begin with, you compare the ratios of those moles to the molar ratio provided by a balanced chemical equation. (The molar ratio is given by the stoichiometric coefficients). For example, if the rat...
Thu Apr 12, 2018 12:31 pm
Forum: Limiting Reactant Calculations
Topic: Knowing if it's Limiting Reactions
Replies: 6
Views: 392

### Re: Knowing if it's Limiting Reactions

Usually in the textbook the question does not explicitly state that it should be a limiting reactant calculation. You are expected to know how to interpret the information given to you to find out that it is a limiting reactant calculation. I suggest doing the textbook problems without looking at wh...
Thu Apr 12, 2018 12:22 pm
Forum: Molarity, Solutions, Dilutions
Topic: Mass percentage
Replies: 8
Views: 590

### Re: Mass percentage

Mass percentages should always add up to 100%. If yours don't, maybe you calculated something wrong, or maybe the question did not explicitly give you all the information. For example, if it is a combustion problem, the question might not have given you information about the O2 that is in the reacta...
Thu Apr 12, 2018 12:18 pm
Forum: Molarity, Solutions, Dilutions
Topic: Units - L or mL? [ENDORSED]
Replies: 15
Views: 1436

### Re: Units - L or mL?[ENDORSED]

If you are giving the answer in mL, make sure you label it, but it is usually better to give your answer in Liters.
Wed Apr 11, 2018 11:10 am
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant
Replies: 9
Views: 2420

### Re: Limiting Reactant

Could someone explain in more detail the "comparing" part of these steps? I do not understand what you do after you have the two different ratios, how do you compare them to know which is your limiting reagent? Using Allen's example, if you have .349 mol of Na, and the ratio of Na to Cl2 ...
Mon Apr 09, 2018 6:11 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Problems
Replies: 1
Views: 130

### Re: Limiting Reactant Problems

After finding the limiting reactant, you must look at the ratio of the limiting reactant to the product. Since the ratio is 1 mol CaC2 to 1 mol CaC2, the maximum yield of 1.56 mol CaC2 is 1.56 mol C2H2. Then you multiply this by the molar mass of C2H2 which is 26.038 g/mol. 1.56 mol x 26.038 g/mol =...