CHEMISTRY COMMUNITY

uhedlund

Expansion will result in an increase in volume and therefore a decrease in pressure. The reaction will likely then favor the side of the reaction that has been expanded since its pressure is lower. Compression will result in a decrease in volume and an increase in pressure. Therefore, the reaction w...

uhedlund

pH is a description of the acidity or alkalinity of a solution. pH<7 is acidic, pH=7 is neutral, and pH>7 is basic. to find pH, use the equation pH=-log(H3O+)

uhedlund

Exothermic reactions are reactions in which heat is released as a result of the reaction (heat is a product). In endothermic reactions, heat is an input (reactant) of the reaction.

uhedlund

Changing the volume results in a change in pressure. If the volume is decreased on one side of the reaction, the reaction will likely favor the other side if the pressure is lower. The reaction will favor the side with lower pressure in this case.

uhedlund

When volume is increased, pressure is decreased. So when volume is decreased on one side of the reaction, the other side of the reaction will be favored due to its lower pressure.

uhedlund

In the ICE box, I stands for initial (so initial concentrations), C stands for Change, and E stands for Equilibrium.

uhedlund

In heterogenous equilibria, some of the components are in different phases (solids, gases, etc.) while in homogenous equilibria the components are all in the same phase.

uhedlund

It is a constant that will probably be included in the equations list for tests.

uhedlund

No, only aqueous solutions and gases are included in calculating the equilibrium constant.

uhedlund

The number should be a whole number; if you get a fraction and have checked your work, multiply all by a number to give you whole numbers.

uhedlund

Using percentages, you can calculate as though the sample were 100 g. Example: 60% O, 30% H, 10% N. Use 60 g O, 30 g H, and 10 g N.

uhedlund

It is always better to show work just in case, but generally for formal charge I do not think it is necessary

uhedlund

Formal charge is the overall charge of an atom or molecule; the most stable charge for a molecule is generally the formal charge closest to 0.

uhedlund

Formal charge shows the overall charge of an atom or molecule; partial charges can be used to indicate polarity of a molecule. For example, in H2O, the H atoms have a partial positive charge while the O atom has a partial negative charge.

uhedlund

For the ligand names, just put them in alphabetical order ignoring any prefixes. Place the transition metal at the end.

uhedlund

When writing the formula, arrange ligands in alphabetical order, ignoring any prefixes.

uhedlund

I think it is important to know about cisplatin, myoglobin, and hemoglobin for the final.

uhedlund

A formal charge closer to zero is more stable than other higher charges.

uhedlund

Elements with a d-orbital may have an expanded octet. This is generally elements in row 3 or lower.

uhedlund

Electronegativity is related to the electron-pulling ability of an atom. Elements at the top right corner of the periodic table have the highest electronegativity, meaning that electronegativity increases as you move right across the table and decreases as you move down.

uhedlund

According to the equation λ = h/p, momentum and wavelength have an inverse relationship. Therefore, as uncertainty in wavelength increases, uncertainty in momentum decreases and vice versa.

uhedlund

Because wavelength=planck's constant/momentum, they have an inverse relationship. As momentum increases, wavelength decreases.

uhedlund

A wavelength smaller than 1*10^-18 cannot be detected; however, it can still be calculated.

uhedlund

Actual yield should generally be lower than theoretical yield; this is due to human error, etc. However, in a laboratory setting if you obtain results in which actual yield>theoretical yield, then it is likely that your sample is contaminated.

uhedlund

Generally, the order of atoms should be in alphabetical order.

uhedlund

Mass percent should always add up to 100%. If you are given non-Oxygen elements and they do not add up to 100, then Oxygen is likely the remaining element and can be used to fill the deficit.

uhedlund

First, you must convert the molecules to moles. Using molar ratios, you can find grams of each of the individual elements. Then convert the masses of the individual elements to moles, and proceed to divide by the smallest number of moles (ex: if H=2, O=4, and H=6 divide all by 2) to find Empirical f...

uhedlund

For a combustion analysis: 1) Convert the given masses of CO2 and H2O to moles 2) Use the molar ratios to find the masses of Carbon and Hydrogen in the original sample 3) Subtract C and H from the mass of the original sample given to find the mass of Oxygen 4) Proceed to find empirical and molecular...

uhedlund

I believe that they will be on the test since they were covered in class and are included under the lecture outlines on Dr. Lavelle's website.

uhedlund

Because the lone pairs are on exactly opposite sides of the molecule, the repulsion from the lone pairs has a net strength of zero (they "cancel out") and so the bond angles will be 90 degrees.

uhedlund

Because repulsions between lone pairs and atoms are significantly stronger than those just between atoms, the repulsion from the lone pairs pushes the atoms closer together, creating smaller bond angles in the molecule.

uhedlund

The bond angles would be slightly less than 90 and slightly less than 120; this is due to the fact that repulsion from the lone pairs causes the angles of the bonds to be slightly smaller since they are being pushed together.

uhedlund

Yes I think the most important thing is just having all 14 problems done!

uhedlund

Yes I heard that it is all of the material from the midterm up until now.

uhedlund

Thank you so much--this is so helpful!

uhedlund

Yes, having different molecular geometry results in the angles between different atoms being different sizes. Lone pairs can play a role in this geometry.

uhedlund

The lone pairs result in a decrease in the size of the angle .

uhedlund

Will peer learning sessions still be at the regular times this week (with the exception of Thursday and Friday) since it is Thanksgiving week?

CHEMISTRY COMMUNITY

Search found 38 matches

Re: Le Chatelier's Principle question

Re: pH

Re: endothermic vs exothermic

Re: Changing Pressure

Re: Increase in Volume Effect on Equilibrium

Re: ICE

Re: Heterogeneous and homogeneous equilibria [ENDORSED]

Re: converting from pressure to concentration

Re: solids in calculating equilibrium constant? [ENDORSED]

Re: Going from empirical to Molecular formula

Re: Empirical Formula [ENDORSED]

Re: Formal Charge

Re: Stable Vs. Formal

Re: Formal Charge vs Partial charge

Re: order of ligand name

Re: Order of ligands

Re: What should we know for the final?

Re: Formal charge on central atom

Re: Elements that break the octet rule

Re: electronegativity

Re: Momentum Uncertainty

Re: Heisenberg and Wavelength

Re: wavelike properties

Re: Actual/Theoretical Yield

Re: Order of Molecules

Re: Mass Percent Composition

Re: Determining Empirical formula

Re: combustion analysis?

Re: Regarding the test... [ENDORSED]

Re: Square Planar

Re: Lone pairs

Re: Seesaw

Re: Homework for week 9

Re: Test 3 material

Re: DOWNLOAD SESSION WORKSHEETS HERE - Sundays 4-6pm (Karen) [ENDORSED]

Re: Multiple different bond angles

Re: Bond Angles for H2O

Re: Peer Learning Sessions [ENDORSED]