## Search found 30 matches

Mon Jun 11, 2018 11:40 pm
Forum: Lewis Acids & Bases
Topic: identifying strong acids
Replies: 2
Views: 258

### identifying strong acids

since we know that strong bases are located in groups 1 and 2 of the periodic table, is there a way to locate where strong acids are?
Mon Jun 11, 2018 1:43 pm
Forum: Limiting Reactant Calculations
Topic: combustion reaction
Replies: 1
Views: 162

### Re: combustion reaction

In a combustion reaction your compound reacts with O2 gas to form Co2 and h2o. To go about this problem, like the nicotine problem, you must determine the molecular formula of your compound. To do so find the mols if each element in your compound as you usually would. Once you have done this you can...
Mon Jun 11, 2018 1:36 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: weak acids
Replies: 4
Views: 299

### weak acids

What should we know about weak acids for the final since we wont have to do calculations?
Sun Jun 03, 2018 10:19 pm
Forum: Hybridization
Topic: hybridization of an atom
Replies: 2
Views: 146

### hybridization of an atom

Some questions on the UA’s worksheets ask to find the hybridization of an atom, for example Cl.

I’m a bit confused on exactly what hybridization is and how I can find it based on the shape ClF3 the question asks to draw.
Sun Jun 03, 2018 8:40 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polar and nonpolar molecules
Replies: 5
Views: 207

### polar and nonpolar molecules

4.25 on the h.w. asks to determine which of the following molecules is polar or non polar.

For example, CH2Cl2

How can I determine this from the structure?
Sun Jun 03, 2018 8:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: hw 4.21 a
Replies: 2
Views: 125

### hw 4.21 a

problem 4.21 asks to write the lewis structure and give the approximate bond angle of:

C2H4

I can draw the structure easily enough, with the two bonded C's in the center but I'm having trouble understanding why it is a trigonal planar, when there five bonds?
Sun May 27, 2018 8:50 pm
Forum: Bond Lengths & Energies
Topic: Test 3 bond length question
Replies: 8
Views: 422

### Test 3 bond length question

There was a question on Test 3 that asked which of the two bonds was longer and whether or not it was the stronger bond of the two? This question confused me because isn't the longer the bond mean that it is the weaker the bond? Am I thinking about this incorrectly?
Sun May 27, 2018 7:30 pm
Forum: Octet Exceptions
Topic: expanded octets
Replies: 5
Views: 305

### expanded octets

Hello!
I was a bit confused on the concept of the expanded octet while drawing lewis structures.
I know that any element with a 3d orbital will have an expanded octet but up to how do I know up to how many electrons it can hold?
Tue May 22, 2018 12:47 am
Forum: Lewis Structures
Topic: 3.63
Replies: 1
Views: 95

### Re: 3.63

Since Xe has an expanded octet you know it can hold more than 8 electrons. To find how many electrons the expanded octet can hold you should first add up the total number of valence electrons of your compound, then draw your lewis structure as you usually would. You will notice that you are missing ...
Sun May 20, 2018 10:30 pm
Forum: Ionic & Covalent Bonds
Topic: ionic character
Replies: 10
Views: 355

### Re: ionic character

Vivian Gonzalez 1A wrote:I am also confused as to what the term covalent character means or is referring to. Can someone please explain?

I think covalent character means the same thing as ionic character. One compound would have a greater covalent character if the difference in electronegativity is greater
Sun May 20, 2018 10:27 pm
Forum: Ionic & Covalent Bonds
Topic: ionic character
Replies: 10
Views: 355

### Re: ionic character

Thank you! This was really helpful!!! How would I be able to determine which element of the compound is more electronegative?
Sun May 20, 2018 10:22 pm
Forum: Ionic & Covalent Bonds
Topic: ionic character
Replies: 10
Views: 355

### ionic character

One of the UA's workshop worksheets included a question that asked to determine which compound has greater ionic character, I was a bit confused on what to do for this question, does it mean which bond is ionic bond is stronger?
Sun May 13, 2018 9:21 pm
Forum: Formal Charge and Oxidation Numbers
Topic: hw 3.53
Replies: 3
Views: 176

### hw 3.53

the question asks: Determine the formal charge on each atom in the following molecules. Identify the structure of lower energy in each pair. I know how to determine the formal charge by using the formal charge equation but I'm not entirely sure how I would identify the structure with the lower energ...
Sun May 13, 2018 8:03 pm
Forum: Resonance Structures
Topic: resonance structures on exams
Replies: 5
Views: 250

### resonance structures on exams

If a question asks us to draw the Lewis structure would we be required to give all the resonance structures or is one variation of them okay?
Sun May 13, 2018 7:54 pm
Forum: Formal Charge and Oxidation Numbers
Topic: formal charge equation
Replies: 3
Views: 218

### formal charge equation

I was a bit confused on what each term of the formal charge equation meant, can someone give an explanation? When and why are we suppose to use it?
Sun May 06, 2018 10:43 pm
Forum: Molarity, Solutions, Dilutions
Topic: Test 1, Q1 [ENDORSED]
Replies: 4
Views: 403

### Re: Test 1, Q1[ENDORSED]

For part B to find the concentration of the lithium ions you find the moles from the previous question and add the 0.100 mols from the new solution. You then divide by the total volume, which in this problem would be 2.00 L.
Sun May 06, 2018 10:34 pm
Forum: Molarity, Solutions, Dilutions
Topic: Midterm Prep Worksheet- Molarity [ENDORSED]
Replies: 2
Views: 207

### Midterm Prep Worksheet- Molarity[ENDORSED]

One of the questions on a UA worksheet asked to find the molarity of 55.1 g of KCl that was dissolved approximately in 75ml of water and then added to a final volume of 125mL. Trying the problem on my own I initially added the volumes together but when going over the question we used only the final ...
Sun May 06, 2018 12:41 am
Forum: Empirical & Molecular Formulas
Topic: Test 1 Question 7
Replies: 3
Views: 288

### Re: Test 1 Question 7

To find the empirical formula when you are given grams rather than percent mass you can start of by converting the grams into moles while also taking into account the ratio. For example take the 8.45 g of CO2 and divide by the molar mass to get mols of CO2 then use the ratio of 1 mol of C per 1 mol ...
Sun Apr 29, 2018 7:29 pm
Forum: Photoelectric Effect
Topic: h.w. 1.65 [ENDORSED]
Replies: 2
Views: 189

### h.w. 1.65[ENDORSED]

the questions asks: 1.65 The energy required to break a C∫C bond in a molecule is 348 kJ mol 1. Will visible light be able to break this bond? If yes, what is the color of that light? If not, what type of electromagnetic radiation will be suitable? I'm confused on how I would be able to determine wh...
Sun Apr 29, 2018 7:10 pm
Forum: Properties of Light
Topic: Test #2: Q6 [ENDORSED]
Replies: 10
Views: 597

### Re: Test #2: Q6[ENDORSED]

I also used both E=hv and wavelength= c/v and came up with the same answer but using wavelength= hc/E is quicker and would result in less calculator error.
Sun Apr 29, 2018 6:59 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: hw 2.13 [ENDORSED]
Replies: 2
Views: 140

### hw 2.13[ENDORSED]

Question 2.17 asks to Describe the orientation of the lobes of the px-, py-, and pz-orbitals with respect to the reference Cartesian axes.
I'm not sure what the orientation of the lobes means. What exactly should we know about lobes?
Sun Apr 22, 2018 8:10 pm
Forum: Photoelectric Effect
Topic: 1.33 HW Confusion (part a)
Replies: 2
Views: 151

### Re: 1.33 HW Confusion (part a)

Yes, to find the wavelength you can use the de Broglie relationship, since you are given the velocity and know that the mass of the electron is 9.10 x 10^-28
Sun Apr 22, 2018 7:56 pm
Forum: Photoelectric Effect
Topic: hw 1.23 [ENDORSED]
Replies: 3
Views: 136

### hw 1.23[ENDORSED]

Problem 1.23 asks to calculate the wavelength of a photon emitted with energy of 140.511 keV. How would I convert keV into J?
Sun Apr 22, 2018 7:47 pm
Forum: DeBroglie Equation
Topic: Ch.1 #41 [ENDORSED]
Replies: 6
Views: 516

### Re: Ch.1 #41[ENDORSED]

to convert from pm to m in order to use the equation you can multiply 100 pm by 10^-12
Sun Apr 15, 2018 10:19 pm
Forum: Photoelectric Effect
Topic: Example 1.5 [ENDORSED]
Replies: 8
Views: 315

### Re: Example 1.5[ENDORSED]

You should look at the constants worksheet that value is given.
Sun Apr 15, 2018 10:14 pm
Forum: SI Units, Unit Conversions
Topic: moles to atoms [ENDORSED]
Replies: 3
Views: 273

### Re: moles to atoms[ENDORSED]

to convert from mols to atoms you would multiply by Avogadro's number since there are 6.022* 10^23 atoms per 1 mole.
Sun Apr 15, 2018 10:11 pm
Forum: Properties of Electrons
Topic: Photoelectric Effect and its light intensity [ENDORSED]
Replies: 2
Views: 124

### Re: Photoelectric Effect and its light intensity[ENDORSED]

In order for electrons to be ejected, the energy of the photon must be the same as or greater than the work function or threshold energy. The only way to increase the energy of the photon to be able to eject electrons is to increase the frequency of the incoming photon. This results in a shorter wav...
Sun Apr 15, 2018 10:03 pm
Forum: Photoelectric Effect
Topic: work function given in kJ*mol^-1
Replies: 2
Views: 86

### work function given in kJ*mol^-1

If the work function is given in kJ*mol^-1 how would i get rid of the mol^-1 since the units are suppose to be in just J?
Sun Apr 15, 2018 9:50 pm
Forum: Photoelectric Effect
Topic: Module Question 27.A
Replies: 4
Views: 191

### Re: Module Question 27.A

I think the m in this equation is the mass of the electron
Sun Apr 15, 2018 9:44 pm
Forum: Photoelectric Effect
Topic: Quantum World Worksheet question 6b [ENDORSED]
Replies: 1
Views: 92

### Quantum World Worksheet question 6b[ENDORSED]

I had a question on problem 6b which asks what is the maximum energy of the electrons emitted when light of 7.3 * 10^14 Hz is used. Is the maximum energy they're asking you to find the same thing as kinetic energy and therefore would I have to use the equation KE= energy of photon - work function?