Search found 19 matches
- Sun Mar 13, 2016 1:41 pm
- Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
- Topic: Substituent Positions on Cyclohexane
- Replies: 2
- Views: 609
Re: Substituent Positions on Cyclohexane
I think unless it's specified that it's cis structure, substituents should be pointing at opposite directions to reach the most stable state.
- Sun Mar 06, 2016 11:36 pm
- Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
- Topic: Torsional strain (Eclipsed to gauche)
- Replies: 2
- Views: 631
Re: Torsional strain (Eclipsed to gauche)
I'm not totally sure but I think you're right.
- Sun Feb 28, 2016 11:52 am
- Forum: *Alkanes
- Topic: Numbering Cs
- Replies: 1
- Views: 458
Numbering Cs
In lecture Dr. Lavelle said that we were not supposed to use "sum rule" when numbering carbons. So just to clarify, we should put all substituents in alphabetical order and compare all possible numbering options for each of them until we find the first lower number?
Thanks ^^
Thanks ^^
- Sat Feb 20, 2016 1:18 pm
- Forum: *Electrophilic Addition
- Topic: Breaking double bonds
- Replies: 1
- Views: 1996
Breaking double bonds
In Friday's lecture we learned about the reaction between HBr and 2-Butene. In step 1 it is said that one of the C=C double bonds is broken to form a C-H bond. But I thought when breaking C=C double bonds we needed to break both of the bonds to form new ones because the bond energies were different ...
- Tue Feb 09, 2016 3:27 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Winter 2014 Midterm Q8
- Replies: 3
- Views: 1014
Re: Winter 2014 Midterm Q8
I also have the same question. I thought when we derive the overall equation for this reaction we would cancel out the coefficients and get HF(aq)---H+(aq) +F-(aq). Why can't we cancel the coefficients out?
- Mon Feb 08, 2016 9:58 pm
- Forum: Phase Changes & Related Calculations
- Topic: Possible scientific errors
- Replies: 1
- Views: 433
Possible scientific errors
When doing calculations on phase change heat transfer, especially those with multiple steps, I often get answers that are slightly different from what is given on the solution manual. This happens a lot if I do those problems in separate steps. I wonder how much of these errors is considered accepta...
- Mon Feb 08, 2016 12:23 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Entropy change in Volume
- Replies: 1
- Views: 522
Re: Entropy change in Volume
There are 2 formulas for delta S calculation. One is nRln(V2/V1) for change in volume and constant temperature situations. The other is nCln(T2/T1) for change in temperature situations. Use Cv for when there's constant volume and Cp for constant pressure.
Hope it helps. ^^
Hope it helps. ^^
- Mon Feb 08, 2016 12:12 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Winter 2011 Midterm Question 2B
- Replies: 2
- Views: 507
Re: Winter 2011 Midterm Question 2B
For this question, it's not 1mol of monoatomic gas and 1mol of diatomic gas in both containers A &B; it's 1mol of ATOMS in those containers. So it comes out to be 1mol of monoatomic gas in container A and 1/2mols of diatomic gas in container B. So container A contains more particles than contain...
- Thu Feb 04, 2016 4:42 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: standard free energy of reaction
- Replies: 1
- Views: 876
standard free energy of reaction
In Q4 of winter 2011 midterm, there is the equation PCl3(g)+Cl2(g)--->PCl5(g) at equilibrium and delta G for PCl5 & PCl3 are also given. I understand that I need to figure out the delta G(rxn) to solve this problem but since the reaction is at equilibrium, shouldn't delta G(rxn) be 0? Also, in t...
- Sun Jan 31, 2016 11:05 pm
- Forum: Balancing Redox Reactions
- Topic: standard reaction potentials
- Replies: 1
- Views: 424
Re: standard reaction potentials
Because standard reaction potential is an intensive property that does not depend on how many times the rxn occurs. So when balancing the equation and multiplying the half reactions, standard rxn potentials stay the same.
Hope it helps ^^
Hope it helps ^^
- Fri Jan 22, 2016 3:43 pm
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3001985
Re: Chemistry Jokes
One property of liquid is that it can fit into containers of any shape and automatically takes up all the space.
So...cat is a liquid!!
So...cat is a liquid!!
- Sun Jan 17, 2016 9:12 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Homework 8.11
- Replies: 3
- Views: 2357
Homework 8.11
Question 8.11: A piston confines 0.200mol Ne(g) in 1.20L at 25C. part (a)The gas is allowed to expand through an additional 1.20L against a constant pressure of 1.00 atm. To calculate the work done in this situation, I apply the w=-PdeltaV equation, but I really don't understand why -(1.00atm)(1.20L...
- Sun Jan 17, 2016 8:18 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: pressure units
- Replies: 2
- Views: 561
pressure units
In the homework questions I notice they use different units for pressure of gases, sometimes atm, sometimes bar or torr. Are they the same or how do I convert one to another?
- Thu Jan 07, 2016 6:07 pm
- Forum: Phase Changes & Related Calculations
- Topic: Explaining kJ/mol
- Replies: 3
- Views: 1468
Re: Explaining kJ/mol
I think usually we use kJ to describe the the total enthalpy change of a rxn with a chemical equation balanced to its smallest integer coefficients. Take the example of formation of NO2(g) from the course reader, the balanced equation is N2(g)+2O2(g)---->2NO2(g) and the total enthalpy change is 68kJ...
- Sun Nov 29, 2015 11:00 pm
- Forum: Identifying Acidic & Basic Salts
- Topic: Na+ in a reaction
- Replies: 2
- Views: 4154
Re: Na+ in a reaction
I think because Na+ ions are completely dissolved in water and they remain unchanged throughout the reaction. If you write the chemical equation with Na+ it would be "CH3COO-+H2O+Na+<-->OH-+CH3COOH+Na+". Since the same amount of Na+ appear on both sides of the equation they will cancel eac...
- Sun Nov 29, 2015 10:47 pm
- Forum: Lewis Structures
- Topic: Video: Homework 3.37
- Replies: 1
- Views: 557
Video: Homework 3.37
This is an explanation of homework problem 3.37 which is about Lewis structure.
And I apologize for the background noise...
And I apologize for the background noise...
- Sun Nov 22, 2015 10:31 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Homework Question 12.51 A
- Replies: 5
- Views: 1114
Re: Homework Question 12.51 A
I think first you can consider this problem with atomic radius. That is, since chlorine has a larger atomic radius than fluorine, the H-Cl bond is longer than H-F bond, which means HCl has weaker bonds and is more likely to dissociate in water compared to HF. So HCl is a stronger acid. On the other ...
- Wed Nov 11, 2015 1:37 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Homework Problem 11.67
- Replies: 2
- Views: 666
Re: Homework Problem 11.67
I think because the reactants are strongly favored, the reaction to the right can't happen with the original partial pressures. It happens only when one of the products is used up, in this case, H2(g). So we need to calculate the new initial partial pressures in which the reaction to the right stars...
- Fri Nov 06, 2015 5:42 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium and limiting reactant
- Replies: 1
- Views: 6476
Equilibrium and limiting reactant
As K=[product]/[reactant], my understand is that when a reaction reaches equilibrium, products and reactants are both being formed at a constant rate. So when we say a reaction ends, does it mean the reaction is at equilibrium? If so, since the reactants are not literally "used up", how ca...