## Search found 20 matches

Sun Feb 28, 2016 6:18 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Steric Contribution
Replies: 1
Views: 305

### Steric Contribution

In simple terms, what is a steric contribution and in what cases would it yield a favorable/unfavorable contribution?
Sun Feb 28, 2016 6:08 pm
Forum: *Free Energy of Activation vs Activation Energy
Topic: Standard Gibbs free energy and Enthalpies of Activation
Replies: 1
Views: 479

### Standard Gibbs free energy and Enthalpies of Activation

Why is the Standard Gibbs free energy of activation (double dagger) always a positive value? And why is Standard ethalpies of activation (double dagger) always positive?
Sat Feb 27, 2016 1:53 am
Forum: *Alcohols
Topic: Propanol
Replies: 1
Views: 404

### Propanol

For CH3CHOHCH3, it's 2-propanol, but why is it 2-propanol and not just 1-propanol? I thought that if you count the carbons from right to left, the "O" would be attached to the first carbon. Am I just wrongly visualizing it?
Mon Feb 22, 2016 10:21 am
Forum: *Free Energy of Activation vs Activation Energy
Topic: Activation Energy with Relation to k
Replies: 1
Views: 387

### Activation Energy with Relation to k

So, when k is low, Activation energy is high? Why?
Fri Feb 12, 2016 10:29 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pre equilibrium Approach
Replies: 1
Views: 287

### Pre equilibrium Approach

Is the pre equilibrium approach only used when the slow step is preceded by the fast step?
Thu Feb 04, 2016 5:07 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram Inert Electrodes
Replies: 1
Views: 239

### Cell diagram Inert Electrodes

How do we know when we need to write the cell diagram with an inert electrode? For example, how do we know we need Pt l I- l I2 ll Ce4+, Ce3+ l Pt VS Zn2+ l Zn l Ni2+ l Ni ?
Fri Jan 29, 2016 8:45 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Free Expansion
Replies: 4
Views: 709

### Free Expansion

How do we know if a system is doing free expansion and the work is therefore 0?
Mon Jan 25, 2016 12:23 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Determining Spontaneity
Replies: 7
Views: 528

### Determining Spontaneity

So a system is spontaneous when DeltaG is negative and also when Delta S total is positive. But why can't we tell the spontaneity of a system by looking at Delta H? I know when Delta H is negative, it's exothermic, but why can't we tell if the reaction is spontaneous just by looking at Delta H?
Sat Jan 16, 2016 12:34 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Equations for Enthalpies of Formation
Replies: 1
Views: 249

### Equations for Enthalpies of Formation

So, when you're asked to the find the enthalpy of formation for a compound without being given a chemical reaction equation, how are you supposed to know what equation to use? For example, when they just ask us to find C6H6(g), how are we supposed to know that the full chemical equation is 6C(gr) + ...
Fri Jan 08, 2016 12:52 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Formation Enthalpies
Replies: 1
Views: 204

### Formation Enthalpies

So, deltaH = deltaH of the products minus the deltaH of the reactants. Do I just plug in the standard enthalpies of formation just like that or do I have to do something with the signs?
Sat Nov 28, 2015 5:29 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Relation between IOH and ClOH
Replies: 2
Views: 4358

### Relation between IOH and ClOH

So, HF < HCl < HBr < HI, in order of increasing acidity. So then why is IOH < BrOH < ClOH in order of increasing acidity? I know HF is weaker than the other binary acids going down a column because of weaker bond strength, but then why is IOH less acidic than ClOH? Is it because of electronegativity?
Tue Nov 24, 2015 1:08 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strong acids
Replies: 1
Views: 359

### Strong acids

How do we tell if the acid is strong or not? I get the periodic trend of the acidity increasing as you go down a column, but what about acids like H2SO4? Is it something that we're supposed to memorize?
Tue Nov 24, 2015 1:01 am
Forum: Lewis Acids & Bases
Topic: Lewis Acids/Bases and relation to Bronsted Acids/bases
Replies: 1
Views: 6311

### Lewis Acids/Bases and relation to Bronsted Acids/bases

So, every bronsted base is a lewis base, but not every lewis base is a bronsted base. Why is that? And can you give me an example?
Sun Nov 15, 2015 6:09 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ethylenediamine and edta
Replies: 1
Views: 404

### Ethylenediamine and edta

So I know that Ethylenediamine (en) is bidental and edta is hexadental. How does this affect the coordination number of the whole molecule?
Sat Nov 07, 2015 5:00 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q and K
Replies: 1
Views: 213

### Re: Q and K

Q is a ratio of the concentrations of the products and the reactants: (products) / (reactants). At K, the ratio of the products equal the reactants. When Q>K, this means that there is a greater concentration of products than reactants. In order to balance out the concentrations and achieve equilibri...
Fri Oct 30, 2015 1:48 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Polarizability
Replies: 2
Views: 338

### Re: Polarizability

An atom with high polarizabililty tells us that its electron cloud is easily distorted and electrons are more easily pulled away from the central atom. These atoms form bonds with greater covalent character because the electron is pulled further between the two bonding molecules, making it seem like...
Sun Oct 25, 2015 1:37 am
Forum: Dipole Moments
Topic: polarizability in ionic model
Replies: 1
Views: 339

### Re: polarizability in ionic model

Ions that have a higher polarizability means that the electron cloud is distorted, and the electrons are pulled out farther from the nucleus towards the other atom. This results in more covalent character because instead of being given up by one atom and taken up by another, the electrons seem to be...
Fri Oct 16, 2015 1:07 am
Forum: Lewis Structures
Topic: Various Lewis Structures
Replies: 2
Views: 349

### Re: Various Lewis Structures

One version of a Lewis structure may be more stable than the others. So, If it is more stable, it is "better" than the other variations of the Lewis Structure.
Fri Oct 09, 2015 9:25 pm
Forum: Quantum Numbers and The H-Atom
Topic: Quantum numbers in an atom
Replies: 1
Views: 476

### Re: Quantum numbers in an atom

So 1 single electron has 4 numbers to describe it: n, l, ml, and ms. Since the problem has already named 3 of the 4 quantum numbers to describe the electron, we look at ms, the spin of the electron. We have two choices: spin up or spin down (+1/2 or -1/2). So the number of electrons that could have ...
Fri Oct 02, 2015 9:25 pm
Forum: *Shrodinger Equation
Topic: Schrodinger Equation
Replies: 2
Views: 509

### Re: Schrodinger Equation

Schrodinger's wave function equation uses a wave function to describe an electron in an atom.