Search found 22 matches

by Viktor2E
Fri Mar 11, 2016 9:01 pm
Forum: *Alkanes
Topic: Naming compounds with cyclo substituents
Replies: 1
Views: 275

Re: Naming compounds with cyclo substituents

The cyclopropyl should branch off the fifth carbon. It does not directly involve the fifth carbon.
by Viktor2E
Mon Feb 29, 2016 5:41 pm
Forum: *Alkenes
Topic: Alkenes Cis v. Trans Quiz
Replies: 1
Views: 551

Re: Alkenes Cis v. Trans Quiz

Geometric isomers exist only when there are two different substituents at both ends of the double bond. Ethene (H2C=CH2), for example, is an alkene that is not cis or trans, because there are no two different substituents.
by Viktor2E
Sat Feb 27, 2016 2:33 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Reaction Profiles
Replies: 1
Views: 272

Reaction Profiles

How can we tell from a reaction profile whether a reaction is spontaneous? I understand that it must be energetically favorable, but at what point is the activation energy low enough? Do we just assume that it is low enough when the hump is relatively low?
Thanks.
by Viktor2E
Mon Feb 15, 2016 5:19 pm
Forum: General Rate Laws
Topic: Homework 15.5: Positive or negative rate
Replies: 1
Views: 384

Re: Homework 15.5: Positive or negative rate

By convention reaction rates are reported as positive values.
by Viktor2E
Mon Feb 08, 2016 7:39 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Multiple Oxidation Half-Reactions?
Replies: 1
Views: 394

Multiple Oxidation Half-Reactions?

In exercise 14.13, d, the reaction Au + (aq) --> Au(s) + Au 3+ (aq) is given. In the solution, the oxidation half-reaction that is used is Au(s) --> Au 3+ (aq) +3e. I used Au + (aq) --> Au 3+ (aq) +2e but got the same answer for the overall balanced redox reaction. Does it matter which oxidati...
by Viktor2E
Mon Feb 08, 2016 6:10 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Anode and Cathode
Replies: 1
Views: 336

Re: Anode and Cathode

In a galvanic cell, the anode is where oxidation occurs and the cathode is where reduction occurs. In the cell diagram, the anode is given first (left) and the cathode next (right).
by Viktor2E
Sat Feb 06, 2016 8:07 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Midterm 2011 2B
Replies: 2
Views: 506

Re: Midterm 2011 2B

The question specifies that the one mol refers to the amount of atoms not molecules. In the diatomic gas, these atoms are bound together to make half a mol of gas molecules. In the monoatomic gas, the atoms are free. That is why the monoatomic gas has more particles.
by Viktor2E
Sun Jan 31, 2016 1:20 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Final Temp problems
Replies: 3
Views: 366

Re: Final Temp problems

It depends on both the heat capacity of the other substance and the amount of each. Yes, if the heat capacity of the other substance is notably lower than that of water, and there is less mol of that substance, it would be expected that the final temperature is closer to the initial water temperatur...
by Viktor2E
Sun Jan 24, 2016 7:41 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy, Enthalpy, and Entropy
Replies: 3
Views: 7025

Re: Gibbs Free Energy, Enthalpy, and Entropy

The formula for Gibbs Free Energy is ΔG =ΔH-T(in Kelvin)×ΔS. A reaction is spontaneous when Gibbs Free Energy is negative. T is never negative since it is in Kelvin. When the enthalpy, ΔH, is negative and entropy, ΔS, is positive, Gibbs has to be negative (G=(-) ΔH - (+) T ×(+) ΔS = (-)) and the rea...
by Viktor2E
Mon Jan 18, 2016 8:32 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Homework Problem 8.53, Different Equation for Q value
Replies: 1
Views: 346

Re: Homework Problem 8.53, Different Equation for Q value

Because we are given the total heat capacity of the calorimeter. q=mcdeltaT would be used if we were given the specific heat capacity.
by Viktor2E
Mon Jan 18, 2016 8:20 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies: Question 8.77
Replies: 1
Views: 327

Re: Bond Enthalpies: Question 8.77

The kekule structure of benzene is the hexagonal structure with alternating double and single bonds. The resonance structure is the actual structure of benzene where the carbons have resonance bonds. For this question you would calculate the total bond enthalpies of both structures and find the diff...
by Viktor2E
Sun Jan 10, 2016 5:55 pm
Forum: Phase Changes & Related Calculations
Topic: Calculating standard enthalpy
Replies: 2
Views: 429

Re: Calculating standard enthalpy

There are several ways. One of the easiest is using Standard Enthalpies of Formation, H f . Simply add all H f of the products and subtract all H f of the reactants. The resulting value is the standard enthalpy of the reaction. I think we will be given the enthalpy of formation for each compound inv...
by Viktor2E
Fri Dec 04, 2015 2:29 pm
Forum: Amphoteric Compounds
Topic: Amphoteric and Amphiprotic
Replies: 1
Views: 341

Amphoteric and Amphiprotic

Is amphoteric always a more general term than amphiprotic? In other words, an amphoteric substance is not necessarily amphiprotic but an amphiprotic substance is always also amphoteric?
by Viktor2E
Sun Nov 29, 2015 4:37 pm
Forum: Polyprotic Acids & Bases
Topic: How to Know if a base is Polyprotic
Replies: 1
Views: 377

Re: How to Know if a base is Polyprotic

You can look at the total negative charges of the ions to see how many H + ions the base can accept. Ba(OH) 2 has two OH- ions so it can accept two H + , thus the base is polyprotic (diprotic). PO 4 3- has 3 negative charges and can accept three H + , so it is polyprotic (triprotic). SO 4 2- is dipr...
by Viktor2E
Sun Nov 22, 2015 7:07 pm
Forum: Naming
Topic: Formula Order
Replies: 2
Views: 426

Formula Order

What order are the ligands in a formula? Is it alphabetical or based on charge? I have heard that anionic ligands should come first, but I always see the Cl- ligand listed after the NH3.
by Viktor2E
Sun Nov 15, 2015 5:08 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Chelates
Replies: 1
Views: 312

Chelates

What exactly is a chelate? Is anything where a polydentate binds to more than one binding site of the metal atom considered a chelate?
by Viktor2E
Sun Nov 08, 2015 4:24 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Transition Metals and Octets
Replies: 1
Views: 255

Re: Transition Metals and Octets

Atoms want to reach the same electron configuration as a noble gas to be the most stable. For period 2 elements, this means having 8 electrons in the outer shell (2 in s and 6 in p). Transition metals generally have their outermost electrons in the d orbitals, so they can accommodate a total of 18 v...
by Viktor2E
Sun Nov 01, 2015 12:58 am
Forum: Hybridization
Topic: How do you find hybridization?
Replies: 3
Views: 722

Re: How do you find hybridization?

You can look at where the electrons are around the given atom. For benzene, each carbon is bonded to 3 other atoms (2 C's and 1 H), and there has to be a region of high electron density between each bonded atom and the carbon. These three high electron densities are the only ones since there are no ...
by Viktor2E
Sat Oct 24, 2015 3:32 pm
Forum: Ionic & Covalent Bonds
Topic: Structure of a compound bases off of the molecular formula?
Replies: 1
Views: 379

Re: Structure of a compound bases off of the molecular formu

In organic molecules like this one the functional groups (NH2 & COOH in this case) are generally bonded to a carbon. In this condensed formula the NH2 is in brackets to show that it branches off the previous atom (carbon). This also means that it won't be bonded to the next group (COOH). Therefo...
by Viktor2E
Fri Oct 16, 2015 8:41 pm
Forum: Ionic & Covalent Bonds
Topic: Compounds having Ionic/Covalent Characteristics
Replies: 1
Views: 445

Re: Compounds having Ionic/Covalent Characteristics

Here are a couple other properties: Melting/Boiling Point : Since ionic compounds have greater forces of attraction (anions to cations), they have higher boiling and melting points than covalent compounds, where less attraction exists between the molecules. Conductivity : Ionic compounds are general...
by Viktor2E
Sat Oct 10, 2015 3:50 pm
Forum: Lewis Structures
Topic: Elements without any Electrons
Replies: 2
Views: 453

Re: Elements without any Electrons

Did the molecule have a negative charge and potassium a positive one (K + )? In that case the Lewis structure showed an ionic bond where the one valence electron of the potassium atom moved to the molecule. The potassium would be shown without valence dots since its' one valence electron was pulled ...
by Viktor2E
Thu Oct 01, 2015 5:28 pm
Forum: DeBroglie Equation
Topic: Units for DeBroglie Equation
Replies: 4
Views: 843

Units for DeBroglie Equation

Why is it that the DeBroglie equation uses kilograms, as opposed to grams? Thanks.

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