Search found 31 matches

by Diana_Visco_1l
Sun Mar 19, 2017 12:29 pm
Forum: Balancing Redox Reactions
Topic: Winter 2013 Final Q4
Replies: 3
Views: 340

Re: Winter 2013 Final Q4

n = total # of e- transferred in the redox reaction.
Fe2+ goes to Fe ----- 2 e- are transferred, but there are 2 moles, so 2X2= 4.
n= 4
by Diana_Visco_1l
Sun Mar 19, 2017 12:29 pm
Forum: Balancing Redox Reactions
Topic: Winter 2013 Final Q4
Replies: 3
Views: 340

Re: Winter 2013 Final Q4

n = total # of e- transferred in the redox reaction.
Fe2+ goes to Fe ----- 2 e- are transferred, but there are 2 moles, so 2X2= 4.
n= 4
by Diana_Visco_1l
Sun Mar 19, 2017 12:08 pm
Forum: *Alkanes and Substituted Alkanes (Staggered, Eclipsed, Gauche, Anti, Newman Projections)
Topic: Newman Projection
Replies: 2
Views: 601

Re: Newman Projection

All the Newman Projections we have done thus far have been a between TWO carbon atoms. The other carbon atoms are considered if they are bonded to the carbon atoms we are examining. They are drawn on the outside of the circle, whereas the carbon atoms being specifically analyzed are in the center of...
by Diana_Visco_1l
Sun Mar 19, 2017 12:05 pm
Forum: *Constitutional and Geometric Isomers (cis, Z and trans, E)
Topic: Z and E how to tell the difference
Replies: 2
Views: 672

Re: Z and E how to tell the difference

Ensure that you are focussing on the "priority rules," in regards to breaking apart double bonds and giving precedence to elements with higher atomic #. Also looking at the line structure and where H atoms are bonded helps establish the geometry and provides a visual representation of wher...
by Diana_Visco_1l
Fri Mar 17, 2017 7:01 pm
Forum: *Alcohols
Topic: Numbering alcohols
Replies: 2
Views: 429

Re: Numbering alcohols

This thought process works if the described alcohol is an alkane (only single bods present). If the molecule is an alkene (double bond) then, the before the suffix of the alcohol, you must indicate where the double bond is located. This is because an alcohol isn't a terminal atom, numbers are vital ...
by Diana_Visco_1l
Thu Mar 16, 2017 10:11 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 917251

Re: Post All Chemistry Jokes Here

Some simple, yet enjoyable jokes:

Every dipole has its moments.

It takes alkynes to make a world!
by Diana_Visco_1l
Thu Mar 09, 2017 4:59 pm
Forum: *Cycloalkenes
Topic: Order of naming
Replies: 6
Views: 747

Re: Order of naming

According to IUPAC, double bonds and triple bonds take precedence in the order of which the structure is named (this is an exception where alphabetical order doesn't appear).
by Diana_Visco_1l
Sun Mar 05, 2017 10:10 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 917251

Re: Post All Chemistry Jokes Here

Making bad chemistry jokes because all the good ones Argon...
by Diana_Visco_1l
Sun Mar 05, 2017 10:05 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: adsorption?
Replies: 2
Views: 337

Re: adsorption?

The rate of adsorption is governed by the rate of arrival of molecules at the surface and the proportion of incident molecules which undergo adsorption. The rate of adsorption (per unit area of surface) as a product of the incident molecular flux, F , and the sticking probability , S . R(ads) = S . ...
by Diana_Visco_1l
Tue Feb 21, 2017 9:33 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Activation Energy
Replies: 4
Views: 464

Re: Activation Energy

The larger this ratio, the smaller the rate (hence the negative sign.) This means that high temperature and low activation energy favor larger rate constants, and thus speed up the reaction. And because these terms occur in an exponent, their effects on the rate are quite substantial. Therefore, tem...
by Diana_Visco_1l
Tue Feb 21, 2017 9:28 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Units of rate constant k
Replies: 2
Views: 269

Re: Units of rate constant k

Zero order: mol/s
First Order: s^-1
Second Order: L * mol^-1 * s^-1
Third Order: L^2 * mol ^-2 * s^-1
by Diana_Visco_1l
Sat Feb 11, 2017 4:28 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 917251

Re: Post All Chemistry Jokes Here

SHORT BUT SWEET...

How about the chemical workers… are they unionized?
by Diana_Visco_1l
Tue Jan 31, 2017 4:46 pm
Forum: Administrative Questions and Class Announcements
Topic: Quiz 1 Preparation Answers
Replies: 130
Views: 13400

Re: Quiz 1 Preparation Answers (#11)

How many grams of water can be heated from 25.0 degrees Celsius to 100 degrees Celsius by the heat released from converting 49.7g of PbO to Pb? The converting reaction is: PbO(s) + C(s) --> Pb(s) + CO(g) deltaH = -106.9kJ How do I go about setting up this problem in order to solve it? q = (n)ΔH (49...
by Diana_Visco_1l
Thu Jan 26, 2017 9:41 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy and Stability
Replies: 1
Views: 219

Re: Entropy and Stability

When discussing the relationship between entropy in regards to the stability of a system, when a maximum heat source is reached, the point can be considered "stable." The state of maximum thermodynamic stability is reached when entropy is maximized and enthalpy is maximized.
by Diana_Visco_1l
Sat Jan 21, 2017 2:51 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 917251

Re: Post All Chemistry Jokes Here

Q: What do you get when you mix sulfur, tungsten, and silver?
A: SWAG
by Diana_Visco_1l
Thu Jan 19, 2017 9:56 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimeters [ENDORSED]
Replies: 3
Views: 345

Re: Calorimeters [ENDORSED]

A coffee cup calorimeter occurs at constant pressure because it is exposed to the atmosphere, because it is partially unsealed. Therefore, volume is allowed to fluctuate. In contrast, a bomb calorimeter, occurs at constant volume and pressure is allowed to fluctuate because it is completely sealed f...
by Diana_Visco_1l
Thu Jan 12, 2017 2:35 pm
Forum: Phase Changes & Related Calculations
Topic: Irreversible Process
Replies: 1
Views: 287

Re: Irreversible Process

An irreversible process occurs due to the finite gradient between the two states of a particular system. In the irreversible process the initial state of the system and surroundings cannot be restored from the final state and increases decisively and it cannot be reduced back to its initial value. A...
by Diana_Visco_1l
Sun Dec 04, 2016 1:15 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Pi bond vs. sigma bond question [ENDORSED]
Replies: 2
Views: 330

Re: Pi bond vs. sigma bond question [ENDORSED]

It helps to think of a sigma bond as a single bond and a pi bond as a double bond.
by Diana_Visco_1l
Sun Dec 04, 2016 1:09 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: bond order question [ENDORSED]
Replies: 3
Views: 439

Re: bond order question [ENDORSED]

The bond order is 2.5 and not enough for triple bond. Thus the molecule will have a double bond and is a table molecule.
* Bond order is a special relationship for Bond length (thus strength)
by Diana_Visco_1l
Mon Nov 28, 2016 5:40 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: the unit "bar"
Replies: 1
Views: 260

Re: the unit "bar"

The bar is the metric unit of pressure. 1 bar = 100,000 Pascal. 1 atm = 1.01325 bar.
by Diana_Visco_1l
Thu Nov 24, 2016 11:54 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: What does it mean for an equilibrium to favor products or reactants?
Replies: 1
Views: 7544

Re: What does it mean for an equilibrium to favor products or reactants?

When Kc>1 you can also say that kforward>kreverse and inversely if Kc<1 then k reverse>k forward. To favor either the reactants or the products in equilibrium is to say the formation of either the reactants or products is favored, as indicated by the rate constants. If a reaction is not at equilibri...
by Diana_Visco_1l
Mon Nov 14, 2016 9:09 pm
Forum: Naming
Topic: Determining Oxidation [ENDORSED]
Replies: 2
Views: 350

Re: Determining Oxidation [ENDORSED]

Okay so... (en)2 = 0 charge. (CN) = -1 charge (Cl) = -1 charge (Cl) = -1 Charge. By addition, you get: -1 + -1 + -1 = -3. The compound as a whole is not an ion (not a cation or anion)so it has a neutral charge of 0. In this case to make this compound 0, the metal has to have an oxidation number of 3...
by Diana_Visco_1l
Mon Nov 14, 2016 9:03 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Naming coordination compounds
Replies: 1
Views: 330

Re: Naming coordination compounds

The sodium atom on the outside of the parenthesis accounts for a charge of 1+. The ammine is 0 and the Chlorine is -3 ( -1 x 3 atoms). And because the compound is not an ion, you know the total number of oxidation numbers must equal zero (neutral). So... 1 + 0 -3 + x = 0. SOLVE FOR X (oxidation numb...
by Diana_Visco_1l
Thu Nov 10, 2016 11:46 am
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 7348
Views: 917251

Re: Post All Chemistry Jokes Here

Here's a very witty, yet simple humorous joke for your afternoon.
by Diana_Visco_1l
Tue Nov 01, 2016 8:27 pm
Forum: Bond Lengths & Energies
Topic: Bond length, 2012 Midterm Question 6B
Replies: 3
Views: 540

Re: Bond length, 2012 Midterm Question 6B

Follow these steps. 1) Find lewis structures for all ions. 2) Ensure you draw structures correctly. 3) Examine the type of bonds being formed (i.e. single, double, triple, etc). Note: The more bonds that appear between two atoms/ions, the more energy is present, and the closer the pull of electrons ...
by Diana_Visco_1l
Tue Nov 01, 2016 8:22 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: What is MO theory for? [ENDORSED]
Replies: 20
Views: 6642

Re: What is MO theory for? [ENDORSED]

To add on...Molecular orbital theory allows us to understand the probability of finding the electrons at particular points around the molecule. MO Theory also allows us to understand bond order which is significant for the understanding of reactivities. Prior to learning about MO, we learned about t...
by Diana_Visco_1l
Mon Oct 24, 2016 5:40 pm
Forum: Electronegativity
Topic: CO2 vs. CS2 ionic character
Replies: 3
Views: 1148

Re: CO2 vs. CS2 ionic character

When analyzing the ionic character of a compound its important to realize the electronegativity difference between the elements in the compound. For example, C has an electronegativity is 0.8. Where C (2.6 EN) - O (3.4 EN) = 0.8 EN. The same thing goes for CS2 = C (2.6 EN) - (2.6) = 0. The greater t...
by Diana_Visco_1l
Mon Oct 17, 2016 1:05 pm
Forum: Resonance Structures
Topic: Electrons in Resonance [ENDORSED]
Replies: 4
Views: 427

Re: Electrons in Resonance [ENDORSED]

In regards to resonance structures, what factors determine which atoms/ions exhibit the greatest resonance stabilization?
by Diana_Visco_1l
Tue Oct 11, 2016 3:44 pm
Forum: Einstein Equation
Topic: Wavelengths [ENDORSED]
Replies: 3
Views: 492

Re: Wavelengths [ENDORSED]

When solving problems for wavelength, yes its important to understand what the question's units contain, it's important to understand the SI unit system. When using the speed of light formula, and Broglie formula the standard SI unit is m. Thus, you must convert your wavelength (if given in nm) to m...
by Diana_Visco_1l
Tue Oct 04, 2016 2:11 pm
Forum: Student Social/Study Group
Topic: Chemistry Joke
Replies: 18
Views: 1520

Re: Chemistry Joke

To all those chemists that have been agitated by atoms...

Don't trust atoms, they make up everything.

- Your Fellow Chemistry Student,
Diana Visco
by Diana_Visco_1l
Tue Sep 27, 2016 1:53 pm
Forum: Balancing Chemical Reactions
Topic: How familiar should we be with Naming compounds? [ENDORSED]
Replies: 8
Views: 1185

Re: How familiar should we be with Naming compounds? [ENDORSED]

HI, in response to your question...To better understand the periodic table and trends, it is extremely helpful to know the name of common compounds and polyatomic ions. A few resources that have helped me over the few years when I have taken chemistry, include resources like Kahn Academy, Fernbank.e...

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