Search found 121 matches
- Mon Mar 15, 2021 9:46 pm
- Forum: Administrative Questions and Class Announcements
- Topic: THANK YOU DR LAVELLE!
- Replies: 47
- Views: 7031
Re: THANK YOU DR LAVELLE!
Thank you so much, Dr. Lavelle!
- Sun Mar 14, 2021 9:28 pm
- Forum: Zero Order Reactions
- Topic: Proper Units for the rate constant
- Replies: 10
- Views: 676
Proper Units for the rate constant
How do you identify the proper units for the rat constant, k, for each reaction order?
- Sun Mar 14, 2021 8:24 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q and K
- Replies: 16
- Views: 816
Q and K
What are the differences between Q and K?
- Sun Mar 14, 2021 8:16 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Equilibrium constant
- Replies: 2
- Views: 307
Equilibrium constant
How do you solve for Kc, equilibrium concentration?
- Sat Mar 13, 2021 9:23 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nerst Equation
- Replies: 3
- Views: 402
Nerst Equation
Can someone explain the E naut value and what it defines as? I am just slightly confused.
- Fri Mar 12, 2021 11:28 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Sapling Week 9/10 Question #7
- Replies: 5
- Views: 432
Re: Sapling Week 9/10 Question #7
Once you compute the order of each reactant, the rate is equal to k multiplied by the concentration of each reactant to the power of its order. So it would look like rate = k([A]^l)([B]^m)([C]^n) are the l, m, and n the order of the reactants? yes! l is the order for reactant A, m --> B, n --> C Th...
- Fri Mar 12, 2021 11:17 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Sapling Week 9/10 Question #7
- Replies: 5
- Views: 432
Re: Sapling Week 9/10 Question #7
Jasmine Ho 3I wrote:Once you compute the order of each reactant, the rate is equal to k multiplied by the concentration of each reactant to the power of its order.
So it would look like rate = k([A]^l)([B]^m)([C]^n)
are the l, m, and n the order of the reactants?
- Fri Mar 12, 2021 10:47 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Sapling Week 9/10 Question #7
- Replies: 5
- Views: 432
Sapling Week 9/10 Question #7
How do you write the rate law for the reaction where k is the rate constant? I have attempted this problem numerous times, but I still can't get it right.
- Sun Mar 07, 2021 11:19 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Sapling Week 9/10 Question 9
- Replies: 4
- Views: 387
Sapling Week 9/10 Question 9
"The rate constant for this first‑order reaction is 0.870 s−1 at 400 ∘C.
A⟶products
How long, in seconds, would it take for the concentration of A to decrease from 0.730 M to 0.400 M?"
How do you determine the time for the decrease in concentration of A?
A⟶products
How long, in seconds, would it take for the concentration of A to decrease from 0.730 M to 0.400 M?"
How do you determine the time for the decrease in concentration of A?
- Sun Mar 07, 2021 11:09 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Sapling Week 9/10 Question 18
- Replies: 6
- Views: 686
Sapling Week 9/10 Question 18
"Consider the mechanism.
step 1: AB+C⟶A+BC
step 2: AB+BC⟶AB2+C
overall: 2AB⟶A+AB2"
How do you determine which species is an intermediate and which is a catalyst? Any tips or tricks of figuring out which is which?
step 1: AB+C⟶A+BC
step 2: AB+BC⟶AB2+C
overall: 2AB⟶A+AB2"
How do you determine which species is an intermediate and which is a catalyst? Any tips or tricks of figuring out which is which?
- Sun Mar 07, 2021 11:07 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Knowing which formula to use
- Replies: 4
- Views: 375
Knowing which formula to use
Hello, I get confused on which formula to use because there are so many. Is there any tip or tricks of ways to know which formula to be using?
- Sun Mar 07, 2021 11:03 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Sapling Week 9/10 Question 1
- Replies: 8
- Views: 640
Sapling Week 9/10 Question 1
"The rate of the given reaction is 0.600 M/s.
A+4B⟶2C
What is the relative rate of change of each species in the reaction?"
What is the easiest method of solving for the relative rate of change? I get confused on how to do it.
A+4B⟶2C
What is the relative rate of change of each species in the reaction?"
What is the easiest method of solving for the relative rate of change? I get confused on how to do it.
- Sun Mar 07, 2021 10:59 pm
- Forum: Student Social/Study Group
- Topic: Chem 14B Final
- Replies: 86
- Views: 6631
Re: Chem 14B Final
The step up sessions are tremendously helpful because they review all of the concepts that will be on the final and also gives examples to support those concepts as well. I also believe that the textbook problems are extremely helpful as well.
- Sun Mar 07, 2021 10:57 pm
- Forum: Student Social/Study Group
- Topic: Note Taking
- Replies: 145
- Views: 18889
Re: Note Taking
I find that handwriting notes is the best at remembering concepts. For tests, studying the homework problems has helped tremendously because many of them are on the tests. I am not sure how the final will be, but it is good to study the homework questions.
- Sun Feb 28, 2021 11:41 pm
- Forum: Balancing Redox Reactions
- Topic: Sapling Week 7/8: Question 16
- Replies: 2
- Views: 255
Sapling Week 7/8: Question 16
"Consider the generic redox reaction shown. X(s)+Y+(aq)↽−−⇀X+(aq)+Y(s) If the coefficients in the redox reaction are doubled, how will the given quantities be affected for a voltaic cell under nonstandard conditions?" I was confused on how to determine how the quantities would be affected.
- Sun Feb 28, 2021 11:39 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Spontaneous vs Nonspontaneous
- Replies: 4
- Views: 269
Spontaneous vs Nonspontaneous
I had trouble with determining if a reaction is spontaneous or nonspontaneous. Can anyone help me with this concept?
- Sun Feb 28, 2021 11:38 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidizing Agent
- Replies: 33
- Views: 1422
Oxidizing Agent
How do you determine which is the best oxidizing agent and which is the poorest oxidizing agent?
- Sun Feb 28, 2021 11:28 pm
- Forum: *Electrophiles
- Topic: Sapling Week 7/8: Question 7
- Replies: 4
- Views: 1380
Sapling Week 7/8: Question 7
"Complete the half‑reactions for the cell shown, and show the shorthand notation for the cell. The electrode on the left is the anode, and the one on the right is the cathode."
How do you tell which is the correct half-reaction for both cathode and anode?
How do you tell which is the correct half-reaction for both cathode and anode?
- Sun Feb 28, 2021 10:52 pm
- Forum: *Electrophiles
- Topic: Anode vs Cathode
- Replies: 16
- Views: 1511
Anode vs Cathode
I keep on mixing up anode vs cathode. How can you tell them apart? Does anyone have a strategy of remembering the differences?
- Sun Feb 21, 2021 10:18 pm
- Forum: Student Social/Study Group
- Topic: Chem 14B Posting on Chem Community
- Replies: 12
- Views: 865
Chem 14B Posting on Chem Community
If we are a Chem 14B student, are we only restricted to posting in the Chem 14B section or are we allowed to also post a question in the Chem 14A section if one of my questions relate to a topic in Chem 14A?
- Sun Feb 21, 2021 10:16 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: Acids & Bases: Calculating the pH
- Replies: 2
- Views: 332
Acids & Bases: Calculating the pH
How do you calculate the Kb of a solution if you already know the Ka value? I know that I have to subtract the Ka value by 14, but sometimes it comes out wrong. I am confused on why that is.
- Sun Feb 21, 2021 10:05 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidizing vs Reducing
- Replies: 55
- Views: 2787
Oxidizing vs Reducing
What are some good rules to remember which is the oxidizing agent and which is the reducing agent?
- Sun Feb 21, 2021 9:34 pm
- Forum: Calculating Work of Expansion
- Topic: Topic 4A Exercises: 4A. 13
- Replies: 2
- Views: 322
Topic 4A Exercises: 4A. 13
4A-13: "A constant-volume calorimeter was calibrated by carrying out a reaction known to release 3.50 kJ of heat in 0.200 L of solution in the calorimeter (q=−3.50kJ), resulting in a temperature rise of 7.32 °C. In a subsequent experiment, 100.0 mL of 0.200 M HBr(aq) and 100.0 mL of 0.200M KOH(...
- Sun Feb 21, 2021 9:27 pm
- Forum: Van't Hoff Equation
- Topic: Van't Hoff Equation
- Replies: 11
- Views: 778
Van't Hoff Equation
How do you solve for K in the van't hoff equation? I was confused on how to get the ln out and isolate K.
- Thu Feb 18, 2021 12:07 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Irreversible vs. Reversible Work Functions
- Replies: 6
- Views: 535
Irreversible vs. Reversible Work Functions
What is the difference between irreversible and reversible work functions?
- Sun Feb 14, 2021 10:57 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Order of liquid Samples
- Replies: 7
- Views: 528
Order of liquid Samples
"Based on the calculated ΔSvap values, arrange the liquid samples in order from most ordered to least ordered.
C2H5OH, C3H6O, C5H12"
How do you know what is most ordered and what is least ordered?
C2H5OH, C3H6O, C5H12"
How do you know what is most ordered and what is least ordered?
- Sun Feb 14, 2021 9:46 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Sapling Week 5/6: HW #8
- Replies: 2
- Views: 144
Sapling Week 5/6: HW #8
"Calculate the standard molar entropy of vaporization of water at 33.0 °C , given that its standard molar entropy of vaporization at 100.0 °C is 109.0 J⋅K−1⋅mol−1 and the molar heat capacities at constant pressure for liquid water and water vapor are 75.3 J⋅K−1⋅mol−1 and 33.6 J⋅K−1⋅mol−1 , resp...
- Sun Feb 14, 2021 9:42 pm
- Forum: Student Social/Study Group
- Topic: Sapling Week 5/6
- Replies: 3
- Views: 246
Sapling Week 5/6
I just want to double check. Is our Sapling Homework Week 5/6 due on Wednesday, 2/17 instead of today?
- Sun Feb 14, 2021 9:18 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Sapling Week 5/6 HW #7
- Replies: 7
- Views: 440
Re: Sapling Week 5/6 HW #7
Start by dividing the energy supplied by the number of moles to find the molar enthalpy of vaporization for the first part. Then, you can divide that value by the temperature, T, to get the molar entropy of vaporization for the second part. Then just repeat this for the other compound. Hope this he...
- Sun Feb 14, 2021 8:39 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Sapling Week 5/6 HW #7
- Replies: 7
- Views: 440
Sapling Week 5/6 HW #7
"Three liquid samples of known masses are heated to their boiling points with the use of a heater rated at 600.0 W . Once the boiling points of each sample are reached, the samples are heated for an additional 5.79 min , which results in the vaporization of some of each sample. After 5.79 min ,...
- Sun Feb 14, 2021 8:22 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase Changes: delta H and delta S
- Replies: 5
- Views: 666
Phase Changes: delta H and delta S
Why can't you have phase changes in (positive H and negative S) and (negative H and positive S)?
- Sun Feb 14, 2021 8:10 pm
- Forum: Student Social/Study Group
- Topic: Midterm 2
- Replies: 3
- Views: 247
Midterm 2
What lectures are covered in midterm 2?
- Sun Feb 07, 2021 11:26 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling Week 3 & 4: #12
- Replies: 3
- Views: 192
Sapling Week 3 & 4: #12
"Suppose a 3.069 g sample of a second compound, compound B, is combusted in the same calorimeter, and the temperature rises from 25.61 ∘C to 28.68 ∘C. What is the heat of combustion per gram of compound B?" For the heat of combustion, I kept on getting 8.13 kJ/g. I am not sure why this is ...
- Sun Feb 07, 2021 11:22 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Negative Sign
- Replies: 16
- Views: 651
Re: Negative Sign
You would put the negative sign on the side which is exothermic or losing the heat. The one with the higher temperature is exothermic (losing heat), and the one with the lower temperature is endothermic (gaining heat).
- Sun Feb 07, 2021 11:19 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling Hw Week 4 #10
- Replies: 5
- Views: 291
Re: Sapling Hw Week 4 #10
I think you are a little off. The part of your equation that is wrong is the 6.01 * 10^3J/mol. You need to figure out the heat required to melt ice which is moles of ice multiplied by delta H f of water.
- Sun Feb 07, 2021 11:10 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling Week 3/4 #9
- Replies: 3
- Views: 170
Sapling Week 3/4 #9
"If you combine 440.0 mL of water at 25.00 ∘C and 100.0 mL of water at 95.00 ∘C, what is the final temperature of the mixture? Use 1.00 g/mL as the density of water." I know that you have to make them equal to each other, but how do you know which side of the equation you make negative and...
- Sun Feb 07, 2021 11:01 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Sapling Week 3/4 #20
- Replies: 3
- Views: 144
Sapling Week 3/4 #20
Why does q equal to delta U?
- Sun Jan 31, 2021 8:15 pm
- Forum: Student Social/Study Group
- Topic: Sapling Week 3 & 4
- Replies: 2
- Views: 172
Sapling Week 3 & 4
This might be a dumb question, but is Sapling Week 3 & 4 homework due today or next Sunday?
- Sun Jan 31, 2021 8:14 pm
- Forum: Phase Changes & Related Calculations
- Topic: Sapling Week 3 & 4: Question 8
- Replies: 4
- Views: 247
Sapling Week 3 & 4: Question 8
"Carbon disulfide can be prepared from coke (an impure form of carbon) and elemental sulfur. 4C(s)+S8(s)⟶4CS2(l)ΔH∘=+358.8 kJ Calculate the amount of heat absorbed in the reaction of 169 g of carbon with excess sulfur. Calculate the amount of CS2 produced when 397 kJ of heat is absorbed." ...
- Fri Jan 29, 2021 3:50 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ka and Kb
- Replies: 9
- Views: 453
Ka and Kb
How do you know when you have to use either Ka or Kb in calculating the pH of a salt solution?
- Fri Jan 29, 2021 3:21 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Making X negligible
- Replies: 34
- Views: 1572
Making X negligible
What are the rules for when to make X negligible?
- Thu Jan 28, 2021 9:51 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Changing Concentrations
- Replies: 5
- Views: 251
Changing Concentrations
How do you know if one side is + X and the other side is -X for an ICE table equation?
- Thu Jan 28, 2021 12:48 pm
- Forum: Student Social/Study Group
- Topic: Midterm 1
- Replies: 3
- Views: 223
Midterm 1
Till what lecture is the midterm 1 covering?
- Sun Jan 24, 2021 11:00 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Percent Ionization
- Replies: 7
- Views: 392
Percent Ionization
"Muscles produce lactic acid, CH3CH(OH)COOH(aq) , during exercise. Calculate the percent ionization (deprotonation), pH, and pOH of a 0.1029 M solution of lactic acid. The acid‑dissociation (or ionization) constant, Ka , of this acid is 8.40×10−4." How do you find the percent ionization? I...
- Sun Jan 24, 2021 10:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Neutral, unknown, or charged?
- Replies: 6
- Views: 259
Neutral, unknown, or charged?
"A monoprotic weak acid, HA , is ionized according to the reaction HA(aq)+H2O(l)↽−−⇀A−(aq)+H3O+(aq)pKa=3.64 where A− is the conjugate base to HA. For this weak monoprotic acid, the predominant species present at pH 2.30 is neutral, unknown, or charged." How do you tell if it is neutral, un...
- Sun Jan 24, 2021 10:28 pm
- Forum: Ideal Gases
- Topic: Acids & Bases
- Replies: 6
- Views: 415
Acids & Bases
How do you determine if a salt is an acid, base, or neutral?
- Sun Jan 24, 2021 10:21 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Homework Week 2
- Replies: 5
- Views: 362
Sapling Homework Week 2
In some of the problems in Sapling Homework Week 2, I needed to make X negligible. How do you determine if X is supposed to be negligible or not?
- Sun Jan 24, 2021 9:22 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 2 #1
- Replies: 9
- Views: 473
Sapling Week 2 #1
If the Ka of a monoprotic weak acid is 1.6×10−6, what is the pH of a 0.21 M solution of this acid?
I tried solving for the pH, but it always comes out wrong. I am not sure if I am doing the steps correctly. Can someone walk me through it?
I tried solving for the pH, but it always comes out wrong. I am not sure if I am doing the steps correctly. Can someone walk me through it?
- Sun Jan 17, 2021 10:20 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 1 #10
- Replies: 8
- Views: 487
Sapling Week 1 #10
The reaction N2O4↽−−⇀2NO2 is allowed to reach equilibrium in a chloroform solution at 25 ∘C . The equilibrium concentrations are 0.463 mol/L N2O4 and 2.28 mol/L NO2 . Calculate the equilibrium constant, Kc , for this reaction. I was able to get the equation products over reactants, but is it suppose...
- Sun Jan 17, 2021 9:22 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 1 #6
- Replies: 10
- Views: 447
Re: Sapling Week 1 #6
Hi there, What is your question on this topic? Just so you know, you should ask a specific question about a problem, I'm not sure if you get credit for just generally asking for help. I hope this doesn't come off as rude, just letting you know so you can get your points. All the best, Colm Thank yo...
- Sun Jan 17, 2021 9:13 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 1 #6
- Replies: 10
- Views: 447
Sapling Week 1 #6
Consider the reaction at 500°C .
N2(g)+3H2(g)↽−−⇀2NH3(g)Kc=0.061
If analysis shows that the composition of the reaction mixture at 500°C is 1.14 mol⋅ L−1N2 , 5.52 mol⋅ L−1H2 , and 3.42 mol⋅ L−1NH3 , what is the value of the reaction quotient Q?
N2(g)+3H2(g)↽−−⇀2NH3(g)Kc=0.061
If analysis shows that the composition of the reaction mixture at 500°C is 1.14 mol⋅ L−1N2 , 5.52 mol⋅ L−1H2 , and 3.42 mol⋅ L−1NH3 , what is the value of the reaction quotient Q?
- Sun Jan 17, 2021 8:20 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 1 #9
- Replies: 4
- Views: 459
Sapling Week 1 #9
At equilibrium, the concentrations in this system were found to be [N2]=[O2]=0.300 M and [NO]=0.400 M. N2(g)+O2(g)↽−−⇀2NO(g) If more NO is added, bringing its concentration to 0.700 M, what will the final concentration of NO be after equilibrium is re‑established? I ended up getting x= -2.16. I am n...
- Sun Jan 17, 2021 6:49 pm
- Forum: Student Social/Study Group
- Topic: Study Strategies
- Replies: 31
- Views: 1425
Study Strategies
What are some study strategies for Chem 14B?
- Sun Jan 17, 2021 6:43 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Week 1 #3
- Replies: 9
- Views: 371
Sapling Week 1 #3
At a certain temperature, the equilibrium constant, Kc, for this reaction is 53.3.
H2(g)+I2(g)↽−−⇀2HI(g)Kc=53.3
At this temperature, 0.600 mol H2 and 0.600 mol I2 were placed in a 1.00 L container to react. What concentration of HI is present at equilibrium?
H2(g)+I2(g)↽−−⇀2HI(g)Kc=53.3
At this temperature, 0.600 mol H2 and 0.600 mol I2 were placed in a 1.00 L container to react. What concentration of HI is present at equilibrium?
- Sun Jan 17, 2021 6:31 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling HW Week 1: Question 2
- Replies: 2
- Views: 93
Sapling HW Week 1: Question 2
At a certain temperature, 0.600 mol SO3 is placed in a 1.50 L container.
2SO3(g)↽−−⇀2SO2(g)+O2(g)
At equilibrium, 0.180 mol O2 is present. Calculate Kc.
2SO3(g)↽−−⇀2SO2(g)+O2(g)
At equilibrium, 0.180 mol O2 is present. Calculate Kc.
- Mon Jan 11, 2021 12:40 am
- Forum: Student Social/Study Group
- Topic: Weekly Assignments
- Replies: 5
- Views: 247
Weekly Assignments
What are the required things to do every week? Is it just chemistry community and the weekly Sapling homework?
- Mon Jan 11, 2021 12:35 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ice method
- Replies: 2
- Views: 172
Ice method
What does the acronym ICE stand for?
- Mon Jan 11, 2021 12:33 am
- Forum: Ideal Gases
- Topic: Ice method
- Replies: 14
- Views: 845
Ice method
How do you use the ICE method?
- Mon Jan 11, 2021 12:31 am
- Forum: Ideal Gases
- Topic: PV=nRT
- Replies: 74
- Views: 5106
Re: PV=nRT
P= Pressure, V= volume, n= number of moles, R= gas constant, and T= temperature
- Mon Jan 11, 2021 12:25 am
- Forum: Administrative Questions and Class Announcements
- Topic: Sapling Homework
- Replies: 7
- Views: 486
Sapling Homework
How do you log in to Sapling homework if you already bought it last quarter? I am unable to log in.
- Tue Dec 15, 2020 11:02 pm
- Forum: Naming
- Topic: Dentate Naming and Lewis Structures
- Replies: 3
- Views: 339
Dentate Naming and Lewis Structures
How do you tell the difference in the lewis structures for mono, bi, tri, and hexa dentate?
- Tue Dec 15, 2020 11:00 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Oxidation State
- Replies: 4
- Views: 418
Oxidation State
How do you solve for the oxidation state for transition metals?
- Tue Dec 15, 2020 11:00 pm
- Forum: Lewis Acids & Bases
- Topic: Acids & Bases
- Replies: 9
- Views: 819
Acids & Bases
How do you tell which is the acid and which is the base?
- Tue Dec 15, 2020 10:58 pm
- Forum: Limiting Reactant Calculations
- Topic: Limiting Reactant [ENDORSED]
- Replies: 18
- Views: 2264
Limiting Reactant [ENDORSED]
How do you solve for the limiting reactant?
- Tue Dec 15, 2020 10:57 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical Formulas
- Replies: 4
- Views: 1163
Empirical Formulas
How do you solve for the empirical formula?
- Sat Dec 12, 2020 7:01 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Strong & Weak Acids and bases
- Replies: 3
- Views: 338
Strong & Weak Acids and bases
How do you tell if it is a strong or weak acid or base?
- Tue Dec 08, 2020 12:24 am
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polar bonds
- Replies: 3
- Views: 287
Polar bonds
How do you know if a molecule is polar or nonpolar?
- Sun Dec 06, 2020 9:04 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Textbook 2E13C
- Replies: 3
- Views: 236
Re: Textbook 2E13C
I am not exactly sure about this problem because I did not do it yet. But, there are sometimes more than one way that you can make the Lewis structure.
- Sun Dec 06, 2020 8:59 pm
- Forum: General Science Questions
- Topic: midterm 2 answers
- Replies: 30
- Views: 2371
Re: midterm 2 answers
The professor does not allow you to see the midterm 2 answers, but the TA does allow you to set up appointments where you can go over the answers with them.
- Sun Dec 06, 2020 8:58 pm
- Forum: Student Social/Study Group
- Topic: Practice Exam for Final
- Replies: 23
- Views: 1407
Re: Practice Exam for Final
I believe if you check your email. There is a review session that he is going to do where he will go over previous exams.
- Sun Dec 06, 2020 8:45 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sapling Week 9 HW #5
- Replies: 5
- Views: 302
Sapling Week 9 HW #5
"For each metal complex, give the coordination number for the metal species.
[Co(en)2(CO)2]Br "
How do you figure out the coordination number for this? I tried many times, but I still couldn't figure it out.
[Co(en)2(CO)2]Br "
How do you figure out the coordination number for this? I tried many times, but I still couldn't figure it out.
- Sun Dec 06, 2020 6:51 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sapling Week 9 HW #3
- Replies: 5
- Views: 339
Sapling Week 9 HW #3
Which geometry or geometries are common for complexes with a coordination number of 6?
- Sun Nov 29, 2020 11:13 pm
- Forum: Hybridization
- Topic: Sapling #11
- Replies: 19
- Views: 958
Re: Sapling #11
1. Count the number of electron density regions which is 4.
2. You know that s has 1, p has 3, and d has 5. Now, use the number of electron density regions and fill in the hybridizations. So it would come out to sp3.
2. You know that s has 1, p has 3, and d has 5. Now, use the number of electron density regions and fill in the hybridizations. So it would come out to sp3.
- Sun Nov 29, 2020 11:11 pm
- Forum: Hybridization
- Topic: Sapling #12
- Replies: 29
- Views: 1194
Re: Sapling #12
I was confused on this question too, but you have to determine the number of electron density regions. Once you know that, you can count the hybridization out. It has four electron density regions, so the hybridization would be sp3.
- Sun Nov 29, 2020 11:01 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Delocalized vs localized
- Replies: 12
- Views: 752
Re: Delocalized vs localized
Delocalized electrons are electrons that are not associated with only one atom or a covalent bond. Localized electrons display the normal behavior.
- Sun Nov 29, 2020 10:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pair E-
- Replies: 47
- Views: 2257
Re: Lone Pair E-
Yes, Lone Pair electrons do count as an electron density region.
- Sun Nov 29, 2020 4:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sapling Week 7/8 HW #12
- Replies: 8
- Views: 678
Sapling Week 7/8 HW #12
"An organic compound that is distilled from wood has a molar mass of 32.04 g/mol. Its composition by mass is 37.5% carbon, 12.6% hydrogen, and 49.9% oxygen.
Draw the Lewis structure of this compound."
Draw the Lewis structure of this compound."
- Sun Nov 29, 2020 3:41 pm
- Forum: Hybridization
- Topic: Sapling Week 7/8 HW #11
- Replies: 13
- Views: 629
Sapling Week 7/8 HW #11
What is the hybridization of phosphorus in each of the molecules or ions?
- Sat Nov 28, 2020 9:15 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Sapling Week 7/8 HW #5
- Replies: 5
- Views: 339
Sapling Week 7/8 HW #5
How do you identify the axial and equatorial atoms in a 3-D structure?
- Sun Nov 22, 2020 8:58 pm
- Forum: Dipole Moments
- Topic: Dipole-Dipole
- Replies: 10
- Views: 491
Dipole-Dipole
How can you tell if a molecule is dipole-dipole interaction?
- Sun Nov 22, 2020 8:56 pm
- Forum: Bond Lengths & Energies
- Topic: Bond Length vs Size of Molecule
- Replies: 14
- Views: 840
Re: Bond Length vs Size of Molecule
Longer bonds do have a weaker bond, but you also have to consider other factors to determine which boiling point is higher.
- Sun Nov 22, 2020 8:54 pm
- Forum: Bond Lengths & Energies
- Topic: Melting Point
- Replies: 12
- Views: 677
Melting Point
How do you tell which element has a higher melting point?
- Sun Nov 22, 2020 7:23 pm
- Forum: Electronegativity
- Topic: Trick for remembering periodic trends
- Replies: 11
- Views: 3575
Re: Trick for remembering periodic trends
For me, I just remember the different patterns for each periodic trend. I remember which periodic trend is going from bottom left to top right, and which are going from top right to bottom left on the periodic table. I also try to understand why each periodic trend is going in that direction due to ...
- Sun Nov 22, 2020 7:19 pm
- Forum: Coordinate Covalent Bonds
- Topic: Hydrogen bonds
- Replies: 20
- Views: 1431
Re: Hydrogen bonds
N,O, F have high electronegativities, and hydrogen has to bond with elements with high electronegativities. Carbon is not one of them.
- Sun Nov 22, 2020 5:16 pm
- Forum: Lewis Structures
- Topic: Expanded Valence
- Replies: 6
- Views: 465
Re: Expanded Valence
I was also confused on this question as well. I took an educated guess. I saw that it was an ion with a charge so I just added one electron to the expanded valence and got 8 valence electrons. I am not sure if I did it right though.
- Sun Nov 15, 2020 9:49 pm
- Forum: Lewis Structures
- Topic: Lewis acids and bases
- Replies: 23
- Views: 924
Lewis acids and bases
How do you classify a species as a Lewis acid or a Lewis base?
- Sun Nov 15, 2020 9:34 pm
- Forum: Ionic & Covalent Bonds
- Topic: Sapling Week 5/6 HW #4
- Replies: 4
- Views: 852
Sapling Week 5/6 HW #4
"The observed carbon–oxygen bond lengths in carbamate are both 128 pm, whereas the observed carbon–nitrogen bond length is 136 pm. Expected values are shown in the table. Based on the Lewis structures and the bond length data, select the correct statement or statements." I do not understan...
- Sun Nov 15, 2020 8:11 pm
- Forum: Lewis Structures
- Topic: Sapling Week 5/6 HW #3
- Replies: 7
- Views: 276
Sapling Week 5/6 HW #3
"The formulas of the bromate ion, BrO−3, and chlorate ion, ClO−3, are very similar. However, the formulas of the nitrate ion and phosphate ion contain different numbers of oxygen atoms. This is also true for the formulas of the nitrite ion and phosphite ion. Draw the Lewis structures of the nit...
- Sun Nov 15, 2020 2:27 am
- Forum: Ionic & Covalent Bonds
- Topic: Delta Negative and Positive
- Replies: 3
- Views: 136
Delta Negative and Positive
How can you tell if an atom is either slightly negative or slightly positive? In a lecture, he said, "Atom with closer electron pair is slightly negative while the other covalently bonded becomes slightly positive." I don't understand.
- Sat Nov 14, 2020 5:08 pm
- Forum: Octet Exceptions
- Topic: Expanded Octets
- Replies: 5
- Views: 880
Expanded Octets
How do you know which elements are able to have expanded octets?
- Fri Nov 13, 2020 12:32 pm
- Forum: Lewis Structures
- Topic: Lewis Structure for sulfate
- Replies: 2
- Views: 485
Lewis Structure for sulfate
Hi, In the lecture #13, the professor was drawing the lewis structure for sulfate, SO4. I am confused how oxygen can form a covalent bond with sulfur when all 6 valence electrons for oxygen are used up in the 3 lone pairs. Where does the extra valence electron come from in order to form a bond with ...
- Sun Nov 08, 2020 8:59 pm
- Forum: Student Social/Study Group
- Topic: Midterm 2
- Replies: 28
- Views: 1252
Midterm 2
I did not do too well on midterm 1. Does anyone have any tips for studying for midterm 2?
- Sun Nov 08, 2020 8:57 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm 2 Question Count
- Replies: 17
- Views: 725
Re: Midterm 2 Question Count
I do not know the exact question count for midterm 2. If it is like midterm 1, I definitely believe the professor will give you more than enough time for each question.
- Sun Nov 08, 2020 8:54 pm
- Forum: Trends in The Periodic Table
- Topic: Atomic Radii of Ionized Atoms
- Replies: 6
- Views: 164
Re: Atomic Radii of Ionized Atoms
Hi,
I believe this was one of the homework questions from last week (Week 2,3,4 HW). It was Sapling Question #18. If you check out the solution for it, it answers your question thoroughly. Let me know if this helps.
I believe this was one of the homework questions from last week (Week 2,3,4 HW). It was Sapling Question #18. If you check out the solution for it, it answers your question thoroughly. Let me know if this helps.
- Sun Nov 08, 2020 8:48 pm
- Forum: Trends in The Periodic Table
- Topic: # of electrons
- Replies: 23
- Views: 721
Re: # of electrons
Hi, the number of elections is equal to the number of protons (in other words: the atomic number).
- Sun Nov 08, 2020 8:46 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Taking Bio and Chem simultaneously
- Replies: 26
- Views: 2552
Re: Taking Bio and Chem simultaneously
I am also a pre-med student, and I am taking bio and chem together. It depends on the person, but I don't think it's a good idea. I am not the best at science.
- Sun Nov 08, 2020 7:47 pm
- Forum: Electronegativity
- Topic: determining electronegativity
- Replies: 40
- Views: 5992
Re: determining electronegativity
I do not know the way to determine electronegativity, but there is a periodic trend for electronegativity which indicates the increasing electronegativity.
- Sun Nov 01, 2020 8:02 pm
- Forum: Trends in The Periodic Table
- Topic: Tips for remembering
- Replies: 14
- Views: 724
Re: Tips for remembering
To remember the trends for the periodic table, I would just try looking up diagrams of the periodic table on which way each trend is going. For example, the atomic radius increases in size from the top right to bottom right. In my head, I just try to memorize and picture those diagrams and arrows. T...
- Sun Nov 01, 2020 7:58 pm
- Forum: Trends in The Periodic Table
- Topic: Determining size of Atomic Radius
- Replies: 2
- Views: 123
Re: Determining size of Atomic Radius
There are periodic trends for determining the size of the atomic radius. If you look at a periodic table, the smallest atomic radius would be in the top right; then, it would increase from top right all the way down to the bottom right of the periodic table. Attached, there is a picture of the perio...
- Sun Nov 01, 2020 7:53 pm
- Forum: Photoelectric Effect
- Topic: Sapling hw #12
- Replies: 5
- Views: 380
Re: Sapling hw #12
For this question, I used the Rydberg equation where v=R[(1/n^2)-(1/n^2)]. The first n would be the final energy level (1), and the second n would be the initial energy level (5). After you plug in what you know, you will get v, the frequency. After you get the frequency, you plug it into the speed ...