Search found 31 matches
- Tue Jun 12, 2018 7:57 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Angles
- Replies: 3
- Views: 590
Re: Bond Angles
In this case I believe having your answer written as <109.5 is fine, my TA usually doesn't require us to be more specific than that unless the problem specifically states such.
- Tue Jun 12, 2018 7:43 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Dipole Moments
- Replies: 1
- Views: 327
Dipole Moments
Will we be expected to calculate exact dipole moments on the final or will questions be limited to asking us to identify whether the compound is polar or non polar?
- Sun Jun 10, 2018 9:39 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: Strong Base Ionization
- Replies: 2
- Views: 705
Strong Base Ionization
Are strong bases always completely ionized in water?
Thanks in advance!
Thanks in advance!
- Sun Jun 10, 2018 4:17 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: lecture 6/6 [ENDORSED]
- Replies: 3
- Views: 685
Re: lecture 6/6 [ENDORSED]
Oxides of Main Group Elements - As discussed, metal oxides react with water to form strong bases. - Many nonmetal oxides react with water to form acids. Carbon Dioxide + Water <—> Carbonic Acid CO2 (g) + H2O (l) <—> H2CO3 (aq) Sulfur Dioxide = Water <—> Sulphurous Acid SO2 (g) + H2O (l) <—> H2SO3 (a...
- Sat Jun 09, 2018 8:34 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2984929
Re: Post All Chemistry Jokes Here
A photon checks into a hotel and is asked if he needs any help with his luggage. He says, "No, I'm traveling light."
- Sat Jun 09, 2018 8:32 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2984929
Re: Post All Chemistry Jokes Here
If you're not part of the solution, you're part of the precipitate.
- Sat Jun 09, 2018 8:29 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2984929
Re: Post All Chemistry Jokes Here
Did you hear Oxygen went on a date with Potassium?
It went OK.
It went OK.
- Thu May 31, 2018 10:25 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Helpful Chart
- Replies: 18
- Views: 1478
Helpful Chart
This post doesn't have a question, just a chart from my TA that might make memorization easier! # of regions of e- density. arrangement of e- densities (bond angles). 2 linear (180) 3 trigonal planar (120) 4 tetrahedral (109.5) 5 trigonal bipyramidal (120, 90) 6 octahedral (90)
- Thu May 31, 2018 10:13 am
- Forum: Hybridization
- Topic: Hybridization
- Replies: 2
- Views: 380
Re: Hybridization
Hybridization is the concept of mixing atomic orbitals into new hybrid orbitals suitable for the pairing of electrons to form chemical bonds.
- Thu May 31, 2018 10:10 am
- Forum: Hybridization
- Topic: VSEPR
- Replies: 11
- Views: 1491
Re: VSEPR
Valence - Shell - Electron - Pair - Repulsion Model
- Thu May 31, 2018 10:09 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR AXE
- Replies: 4
- Views: 525
VSEPR AXE
When using the VSEPR formula, knowing that for E you write the number of electron pairs, what would you write when dealing with a radical? Do you put E 0.5 or is it still E 1?
Thanks in advance!
Thanks in advance!
- Tue May 22, 2018 12:12 pm
- Forum: Bond Lengths & Energies
- Topic: Test 3 Material Question
- Replies: 3
- Views: 531
Re: Test 3 Material Question
I believe test 3 covers what we've learned in chapter 3 and those two small sections in chapter 6.
Hope this helps!
Hope this helps!
- Fri May 18, 2018 9:42 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 2984929
Re: Post All Chemistry Jokes Here
Helium walks into a bar.
The bar tender says, "We don't serve noble gasses in here."
Helium doesn't react.
The bar tender says, "We don't serve noble gasses in here."
Helium doesn't react.
- Thu May 17, 2018 12:03 am
- Forum: Ionic & Covalent Bonds
- Topic: Formaldehyde Formula
- Replies: 2
- Views: 475
Formaldehyde Formula
Why is it that the chemical formula for formaldehyde is HCHO and not H2CO?
- Thu May 17, 2018 12:01 am
- Forum: Ionic & Covalent Bonds
- Topic: Question 3.11
- Replies: 1
- Views: 306
Re: Question 3.11
It's pretty much just calculating the ground state in reverse. Knowing that the noble gas is Argon, the metal(s) must come from the fourth period of the periodic table since Argon is located in the third. a) 3d6 tells you there is 6 electrons, but you need to add an additional 3 since the question s...
- Mon May 14, 2018 12:02 am
- Forum: Lewis Structures
- Topic: Formal Energy / Formal Charge [ENDORSED]
- Replies: 2
- Views: 559
Formal Energy / Formal Charge [ENDORSED]
Are formal energy and formal charge the same thing?
- Mon May 14, 2018 12:00 am
- Forum: Lewis Structures
- Topic: Dots or lines [ENDORSED]
- Replies: 5
- Views: 705
Re: Dots or lines [ENDORSED]
My TA did this as well and he said it would be fine to do on a test or quiz since the two dots or the one line are referring to the same two electrons. He actually recommended using lines on the test instead of individual dots because it's a huge time saver if you're dealing with a complicated Lewis...
- Sun May 13, 2018 11:46 pm
- Forum: Resonance Structures
- Topic: Number of Resonance Strucutres
- Replies: 3
- Views: 581
Re: Number of Resonance Strucutres
Finding the formal charge is usually a good indicator for how many resonance structures you'll have. For example, if you calculate the formal charges in PO4^3-, you find that P= +1 and 0= -1. Knowing the formal charges can cancel, and also that there are four times as many O as P, you know you'll ha...
- Sun May 06, 2018 6:08 pm
- Forum: Trends in The Periodic Table
- Topic: Trends to Know
- Replies: 12
- Views: 1279
Trends to Know
For the midterm, I know the important trends to know are atomic radii, ionic radii, and ionization energy. Are there any other trends I'm forgetting that we should definitely know? And if so, could you explain the trend?
- Sun May 06, 2018 5:59 pm
- Forum: Ionic & Covalent Bonds
- Topic: Midterm Topics [ENDORSED]
- Replies: 33
- Views: 4707
Re: Midterm Topics [ENDORSED]
Will we need to be able to draw electron configurations for the midterm?
- Sun May 06, 2018 5:23 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Moles [ENDORSED]
- Replies: 2
- Views: 443
Re: Moles [ENDORSED]
"mole of solute stay the same" implies that even if the concentration of a substance is changed, if the same amount of the original substance is the same then the moles would remain unchanged. in terms of a practical example, if you have a cup of coke and you pour water into it, although t...
- Sun Apr 22, 2018 4:38 pm
- Forum: Photoelectric Effect
- Topic: 1.25 part B
- Replies: 2
- Views: 316
1.25 part B
To find how much energy is emitted by 5.00mg of sodium atoms, do you have to convert the 5.00mg of sodium to atoms and then multiply by the energy found in part A? Thanks in advance.
- Sun Apr 22, 2018 4:32 pm
- Forum: Photoelectric Effect
- Topic: 1.33 Part D
- Replies: 2
- Views: 336
1.33 Part D
(d) What kind of electromagnetic radiation was used?
For part C, I found a wavelength of 8.8. nm but I am unaware exactly how to find which region this falls into.
For part C, I found a wavelength of 8.8. nm but I am unaware exactly how to find which region this falls into.
- Sun Apr 22, 2018 12:18 pm
- Forum: Photoelectric Effect
- Topic: Energy spectrum
- Replies: 4
- Views: 396
Re: Energy spectrum
Each line represents a different jump in energy that an electron of an atom could make. The energy difference between these levels is given by the Rydberg formula.
- Wed Apr 11, 2018 12:14 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Homework Problem G17
- Replies: 2
- Views: 1282
Re: Homework Problem G17
Also, sorry if the -1's throw you off, the superscript button wasn't working correctly, but they're just there for unit notation.
- Wed Apr 11, 2018 12:11 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Homework Problem G17
- Replies: 2
- Views: 1282
Re: Homework Problem G17
This is similar to example G.2. For both a and b, since volume and molarity are given, you just multiply those quantities by the molar mass. (see formulas n = cV and m = nM) First, remember to convert 250 mL to 0.250L a) molar mass CuSO4 = 159.60 g/mol -1 mass of CuSO4 = (0.20mol/L -1) x (0.250L) x ...
- Tue Apr 10, 2018 7:55 pm
- Forum: SI Units, Unit Conversions
- Topic: Units for Answer
- Replies: 10
- Views: 1147
Re: Units for Answer
In this problem specifically (L.35), the question asks for your answer in kilograms. If the question didn't ask for your answer in kg, it would be okay to leave your answer in grams. If you are ever unsure, you could just write your answer as " 5.09 x 10^5 g Fe or 509 kg Fe ", since it's u...
- Tue Apr 10, 2018 7:44 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Fundamentals HW G.13
- Replies: 1
- Views: 434
Fundamentals HW G.13
G.13 To prepare a fertilizer solution, a florist dilutes 1.0L of 0.20M NH4NO3 (aq) by adding 3.0L of water. The florist then adds 100. mL of the diluted solution to each plant. How many moles of nitrogen atoms will each plant receive? I first used M1V1 = M2V2 to find the concentration of diluted NH4...
- Tue Apr 10, 2018 5:01 pm
- Forum: Significant Figures
- Topic: Scientific notation [ENDORSED]
- Replies: 7
- Views: 917
Re: Scientific notation [ENDORSED]
Sig figs should be enough, but for really small or really large numbers I would use scientific notation to be concise.
- Tue Apr 10, 2018 4:58 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Question on Self Test G.3A
- Replies: 1
- Views: 282
Re: Question on Self Test G.3A
Micromol and millimol differ by a factor of 1000. Therefore, to go from mol to mmol, divide 1.44umol by 1000 to get 0.0014 mmol.
- Sat Apr 07, 2018 1:36 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: HW G.7
- Replies: 2
- Views: 255
Re: HW G.7
I'm pretty sure it doesn't need to be completely dissolved.