## Search found 22 matches

Mon Mar 13, 2017 6:53 pm
Forum: General Rate Laws
Topic: Difference between equilibrium constant and rate constant
Replies: 1
Views: 3188

### Difference between equilibrium constant and rate constant

What is the difference between these two constants and what are they each describing in a reaction?
Sat Mar 04, 2017 4:26 pm
Forum: *Alkanes
Topic: Question 4.30 in the organic text book [ENDORSED]
Replies: 2
Views: 412

### Question 4.30 in the organic text book[ENDORSED]

This question reads: the activation energy, in organic reaction is known to be 125 kJ•mol-1. Will this reaction occur at room temperature. Could someone help with this thanks!
Sat Mar 04, 2017 3:39 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8019
Views: 1403952

### Re: Post All Chemistry Jokes Here

Did you hear about the man who got cooled to absolute zero? He's 0K now.
Tue Feb 21, 2017 10:34 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: Quiz 2 Practice Question 11
Replies: 2
Views: 341

### Quiz 2 Practice Question 11

This question says: The rate constant for the reaction A --> B is 25 min-1 at 298 K and 35 min-1 and 350 K. Calculate the value of the rate constant at 770 K, give your answer in min-1. I am having trouble figuring out how to set up this problem could someone help thanks!
Tue Feb 14, 2017 4:26 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Winter 2013 Midterm Q2A
Replies: 10
Views: 930

### Re: Winter 2013 Midterm Q2A

On part A, how would we determine that the q of the water is the one that is negative in the equation qice=-qwater?
Mon Feb 06, 2017 10:53 am
Forum: Balancing Redox Reactions
Topic: Chapter 14 Question 3
Replies: 7
Views: 834

### Chapter 14 Question 3

This problem states, balance the following skeletal equations by using oxidation and reduction half reactions. All the reactions take place in acidic solution. The reaction is Cl2(g) + S2O3 2-(aq) --> Cl- (aq)+ SO4 2- (aq). I understand how to get which agent is oxidizing and which one is reducing b...
Tue Jan 31, 2017 10:07 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Chapter 9 Question 43
Replies: 1
Views: 1090

### Chapter 9 Question 43

This question states: Suppose that 50.0 g of H2O(l) at 20.0° C is mixed with 65.0g of H2O(l) at 50.0°C at constant atmospheric pressure in a thermally insulated vessel. Calculate ∆S and ∆Stot for the process. Could someone help me with this?
Tue Jan 31, 2017 10:01 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Resources
Replies: 3
Views: 397

### Re: Resources

I find that UA session and TA office hours are extremely helpful!
Tue Jan 24, 2017 3:29 pm
Forum: Phase Changes & Related Calculations
Topic: Quiz prep 1 question 6
Replies: 1
Views: 258

### Quiz prep 1 question 6

This question asks what mass of propane C3H8(g) must be burned to supply 2580 kJ of heat? The standard enthalpy of combustion of propane at 298 K is -2220 kJ/mol. Since there is no change in temperature how would I go about solving this problem?
Thu Jan 19, 2017 12:42 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Chapter 8 problem 21 [ENDORSED]
Replies: 3
Views: 563

### Chapter 8 problem 21[ENDORSED]

Problem 21 states: A piece of copper of mass 20.0 g at 100.0°C is placed in a vessel of negligible heat capacity but containing 50.7 g of water at 22.0°C. Calculate the final temperature of the water. Assume that no energy is lost to the surroundings. Could someone help me out with this problem in s...
Fri Jan 13, 2017 4:17 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy vs Energy
Replies: 2
Views: 454

### Re: Enthalpy vs Energy

Enthalpy is the heat flowing in or out of a system at a constant pressure that depends on the amount of substance present. Enthalpy will equal energy unless the reaction is performed at a very high pressure or there is a significant change in volume, which can be seen because the formula for enthalp...
Thu Dec 01, 2016 6:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Final 2012: Q4
Replies: 1
Views: 431

### Re: Final 2012: Q4

A radical occurs when there are an odd number of valence electrons, so instead of a lone pair, there is just a single electron. For instance, in the hydroxide radical, there is a single atom where a lone pair would normally be.
Tue Nov 29, 2016 12:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Both Roots are positive
Replies: 2
Views: 306

### Re: Both Roots are positive

There will be one root that is too big to subtract from the original concentration or partial pressure, so you would use the smaller one of the two.
Mon Nov 21, 2016 12:56 pm
Forum: Conjugate Acids & Bases
Topic: pH and pOH
Replies: 4
Views: 815

### Re: pH and pOH

p is a shorthand notation for -log that is written to simplify the equations
Tue Nov 15, 2016 4:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Quiz 3 Prep Fall 2014 [ENDORSED]
Replies: 1
Views: 289

### Quiz 3 Prep Fall 2014[ENDORSED]

On question number 6, it asks what conditions favor SO2(g) production in the equation 2SO3(g) <-> 2SO2(g) + O2(g). I understand how increasing the temperature would favor the products but the other condition is low pressure. Wouldn't lowering the pressure cause the molecule to shift towards the reac...
Thu Nov 10, 2016 9:33 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8019
Views: 1403952

### Re: Post All Chemistry Jokes Here

I blew up my chemistry experiment... oxidants happen
Tue Nov 01, 2016 10:38 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: 2012 Midterm Q3c
Replies: 2
Views: 503

### Re: 2012 Midterm Q3c

In addition to the wavelengths of visie light I think we also should know the wavelengths of infrared and ultraviolet light and where they come in the spectra either before or after visible light.
Mon Oct 24, 2016 3:56 pm
Forum: Lewis Structures
Topic: Expanded Octets
Replies: 1
Views: 321

### Expanded Octets

I am wondering why Xe can have an expanded octet even though it is a noble gas with all its orbitals filled?
Tue Oct 18, 2016 3:27 pm
Forum: Ionic & Covalent Bonds
Topic: Difference between Ionic bonds and Molecules Lewis Strructure [ENDORSED]
Replies: 1
Views: 373

### Re: Difference between Ionic bonds and Molecules Lewis Strructure[ENDORSED]

The brackets around a ionic lewis structure are meant to show that their is an overall charge on the entire molecule, not just certain elements within the molecule.
Tue Oct 11, 2016 3:46 pm
Forum: DeBroglie Equation
Replies: 3
Views: 570

### Re: Workbook Prep Quiz Answers

Yes, the answers in the workbook have the correct amount of significant figures!
Wed Oct 05, 2016 10:39 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Post Module #5
Replies: 1
Views: 294

### Re: Heisenberg Post Module #5

You would be correct, this is due to the fact that the position and momentum of a particle are complementary properties, meaning if one property is known then the other cannot be known simultaneously. As your measurement for one property gets more accurate, the other measurement becomes less accurate.
Tue Sep 27, 2016 1:56 pm
Forum: Significant Figures
Topic: Which number to use?
Replies: 6
Views: 831

### Re: Which number to use?

When doing calculations, use as many sig figs as possible up until you have calculated your final answer, which should include the same amount of sig figs as the smallest numerical data being used. For instance if the smallest number in the original data has only 3 sig figs, then in your final answe...