Search found 22 matches

by gracehart
Fri Mar 17, 2017 11:14 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1017723

Re: Post All Chemistry Jokes Here

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by gracehart
Tue Mar 07, 2017 11:47 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1017723

Re: Post All Chemistry Jokes Here

Two chemists go into a bar. The first one says "I think I'll have an H2O." The second one says "I think I'll have an H2O too" — and he died.
by gracehart
Fri Mar 03, 2017 1:09 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1017723

Re: Post All Chemistry Jokes Here

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by gracehart
Fri Feb 24, 2017 10:13 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1017723

Re: Post All Chemistry Jokes Here

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by gracehart
Fri Feb 17, 2017 12:17 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1017723

Re: Post All Chemistry Jokes Here

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by gracehart
Fri Feb 10, 2017 1:40 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1017723

Re: Post All Chemistry Jokes Here

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by gracehart
Wed Feb 01, 2017 12:53 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7606
Views: 1017723

Re: Post All Chemistry Jokes Here

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by gracehart
Wed Jan 25, 2017 11:17 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Question 8.87
Replies: 1
Views: 267

Question 8.87

Could you explain the process for solving this problem? I know its a step-by-step process, but I'm confused on which values to use in each step.

8.87) How much heat is required to convert a 42.30-g block of ice at -5.042 degrees Celsius into water vapor at 150.35 degrees Celsius?

Thanks!
by gracehart
Fri Jan 20, 2017 5:20 pm
Forum: Phase Changes & Related Calculations
Topic: 8.29 in Textbook [ENDORSED]
Replies: 2
Views: 346

8.29 in Textbook [ENDORSED]

How do you know that NO2 has a higher molar heat capacity than NO?
by gracehart
Fri Jan 13, 2017 12:42 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Question 8.9
Replies: 3
Views: 251

Question 8.9

Could someone explain the process of solving this problem? Thanks! An ideal gas in a cylinder was placed in a heater and gained 5.50 kJ of energy as heat. If the cylinder increased in volume from 345 mL to 1845 mL against an atmospheric pressure 750. Torr during the process, what is the change in in...
by gracehart
Thu Dec 01, 2016 1:04 am
Forum: Lewis Acids & Bases
Topic: Difference between Bronsted and Lewis
Replies: 1
Views: 343

Difference between Bronsted and Lewis

What is the difference between Bronsted-Lowry and Lewis acids and bases?
by gracehart
Tue Nov 22, 2016 7:49 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic and Endothermic
Replies: 4
Views: 761

Exothermic and Endothermic

Hi!

Could someone please explain how the endothermic and exothermic reactions are affected by temperature change?

Thank you!
Grace
by gracehart
Tue Nov 22, 2016 7:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Homework 11.67
Replies: 1
Views: 197

Homework 11.67

11.67: The reaction 2HCL (g) <---> H 2 (g) + Cl 2 (g) has K=3.2 x 10 -34 at 298K. The initial partial pressures are H 2 , 1.0 bar; HCl, 2.0 bar; and Cl 2 , 3.0 bar. At equilibrium there is 1.0 mol H 2 (g). What is the volume of the container? Could you please explain how to solve this? Thanks!
by gracehart
Fri Nov 11, 2016 2:56 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Homework 17.33
Replies: 2
Views: 341

Homework 17.33

Could you explain how to answer this homework question? 17.33 Which of the following ligands can be polydentate? If the ligand can be polydentate, give the maximum number of places on the ligand that can bind simultaneously to a single metal center: (a) chloride ion; (b) cyanide ion; (c) ethylenedia...
by gracehart
Thu Nov 03, 2016 1:34 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Homework 4.51 - Molecular Orbital-Level Diagrams
Replies: 1
Views: 308

Homework 4.51 - Molecular Orbital-Level Diagrams

4.51 Draw a molecular orbital-level diagram and determine the bond order expected for each of the following diatomic species: (a) Li2 (b) Li2+ (c) Li2-.

Could you explain briefly the steps for drawing the diagram?
by gracehart
Wed Oct 26, 2016 11:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Ionic Character in Molecules
Replies: 1
Views: 435

Ionic Character in Molecules

What is the easiest way to determine which molecules have the most ionic character? I know it has to do with electronegativity, but could you just clarify the process of determining which have the most ionic character?

Thank you!
by gracehart
Mon Oct 17, 2016 6:19 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 2.37 [ENDORSED]
Replies: 7
Views: 2285

Homework 2.37 [ENDORSED]

2.37: Which of the following statements are true for many-electron atoms? If false, explain why. (a) The effective nuclear charge is independent of the number of electrons present in an atom. (b) Electrons in an s-orbital are more effective than those in other orbitals at shielding other electrons f...
by gracehart
Thu Oct 13, 2016 11:03 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: p-orbitals
Replies: 1
Views: 185

p-orbitals

What is the significance of the px, py, pz specifications? Why do we indicate the x, y, and z as opposed to just writing p?
by gracehart
Thu Oct 06, 2016 12:17 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework 1.13 [ENDORSED]
Replies: 3
Views: 377

Re: Homework 1.13 [ENDORSED]

Thank you so much! What value did you use for R?
by gracehart
Thu Oct 06, 2016 12:12 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework 1.25 part b [ENDORSED]
Replies: 1
Views: 256

Homework 1.25 part b [ENDORSED]

1.25: Sodium vapor lamps, used for public lighting, emit yellow light of wavelength 589 nm. How much energy is emitted by a) an excited sodium atom when it generates a photon b) 5.00 mg of sodium atoms emitting light at this wavelength c) 1.00 mol of sodium atoms emitting light at this wavelength I ...
by gracehart
Thu Oct 06, 2016 11:36 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework 1.13 [ENDORSED]
Replies: 3
Views: 377

Homework 1.13 [ENDORSED]

1.13: a) Use the Rydberg formula for atomic hydrogen to calculate the wavelength of radiation generated by the transition from n=4 to n=2.

Which equation should we be using for this problem? If possible could you walk through the steps of solving this problem?
by gracehart
Fri Sep 30, 2016 1:55 pm
Forum: Administrative Questions and Class Announcements
Topic: Fundamentals
Replies: 2
Views: 353

Re: Fundamentals

Could someone please explain the rules for naming anions? I'm still a little bit confused and don't really remember the rules much from high school chem.Thanks!

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