CHEMISTRY COMMUNITY

nolansheow3G

For the most part, when questions ask you to determine which compound is an "acid", they are referring to the Bronsted definition of an acid.

nolansheow3G

What makes a ligand "neutral"?

nolansheow3G

Our TA said it was purely a personal preference. There is no difference between the two so don't get too confused.

nolansheow3G

Can somebody explain the biological importance of coordination compounds and how these compounds actually influence biological systems?

nolansheow3G

Bronsted Acids and bases are more commonly used and considered a more widely accepted definition. Just be careful with what the problem asks so you know which definition to use.

nolansheow3G

The formula for Zinc Nitrate is Zn(NO3)2.

Theoretically you could use Zn(OH)2 (base) and add 2HNO3 (acid) to get Zinc Nitrate and water, though I'm not sure if this is possible in real life.

nolansheow3G

Another quick (but much less reliable way) would be to think about common compounds that have just one more or one less proton. Ex: Given NH4+, try to recall a compound you've seen before (NH3) Same with OH- and H20, H30+ and H2O, HNO3 and NO3-, etc. I would only recommend using this method if you a...

nolansheow3G

It depends on if the molecule the two hydrogen atoms are attached to will be stable. Molecules tend to exist in the most stable state, so if removing the hydrogen makes the molecule unstable, it isn't likely to donate two hydrogen atoms. For example: H2SO4 is likely to lose the two hydrogen because ...

nolansheow3G

HF is a weak acid because fluorine is relatively small compared to the other atoms in its group. This makes the bond length shorter and therefore makes the H-F bond relatively strong. A stronger bond results in a weaker acid because HF is less likely to dissociate in to H+ and F-. I'm not exactly su...

nolansheow3G

T shaped has two pairs of unpaired electrons (AX3E2). Trigonal pyramidal has only one pair of unpaired electrons AX3E. Remember that the shape of a molecule is determined both by bonded AND unbonded pairs.

nolansheow3G

Yes, VSEPR is the reason why the shapes exist. The valence shell electron repulsion is what gives molecules their geometric shape, as atoms orient themselves so that they are the farthest distance from eachother (a result of the repulsion).

nolansheow3G

Not exactly - you could memorize each individual shape based on the number of bonded and unbonded pairs. However, you are basically doing the same with the AXE notation and it's extremely helpful to know. You can memorize which AXE formula corresponds to a certain shape, which will make it easier to...

nolansheow3G

Boiling and melting are both physical changes, not chemical changes. Therefore the intermolecular forces are at play - if the intramolecular forces were affected then it would be a chemical change.

nolansheow3G

Also note that induced dipoles are more common in compounds with a larger amount of electrons. So a compound like C6H12 would be more likely to have an induced dipole than CH4.

nolansheow3G

Covalent bonds are intramolecular bonds, which would be the bonds between the oxygen and hydrogen in H2O. Due to the electronegativity difference between hydrogen and oxygen, the electron distribution becomes uneven which allows for intermolecular bonds known as hydrogen bonding.

nolansheow3G

How many valence electrons are in:

[Ar] 3d10 4s2 4p3

[Ar] 3d5 4s2

nolansheow3G

Does electron affinity need to be taken into account when drawing Lewis Dot Structures? I briefly remember Dr. Lavelle mentioning Electron Affinity as we left lecture on Monday.

nolansheow3G

Hi, how do you know the number of valence electrons for transition metals? One of the homework questions asked "How many valence electrons are in Mn?" The answer is 7, but how can you tell?

nolansheow3G

The only elements with full octets are the noble gases. Other elements must bond to form compounds in order to get a full octet. You can use the periodic table to see how many electrons an element has based on its group number.

nolansheow3G

Elements are also the most stable when they have an electron configuration similar to that of a noble gas, which is why most compounds follow the octet rule (with the exception of compounds including H, He, Li, and Be).

nolansheow3G

Start by checking the element's location on the periodic table. Elements in Group 1 have one valence electron, those in group 2 have two valence electrons. Then skip to group 13, under Boron. Group 13 elements have 3 valence electrons, then group 14 has 4, group 15 has 5, and so on until you reach g...

nolansheow3G

As you go down a group, the atomic radius increases because the electrons are at larger distances from the nucleus. As you move across a row, the increased amount of protons pull the electrons closer, making it harder to remove (since protons in nucleus attract) and therefore increase IE. Moving dow...

nolansheow3G

Hi, one of the homework questions asked for how many nodes an F orbital has. Does anyone know? Also, is there a way to find out how many nodes each type has or is it just memorization?

nolansheow3G

How does the photoelectric effect support the idea that electromagnetic radiation has properties of particles?

nolansheow3G

Honestly, I don't think there's any way to show your work for those questions. Maybe just show all your attempts, but even then it gets messy (since we're using pen). I doubt the TA's will care, and if they do - I'm screwed because I didn't show my work ... I just put my final answer.

nolansheow3G

I've always kept significant figures running in the calculator, regardless of whether you're using multiplication, division, addition, or subtraction. While the rules above about significant figures is correct, most, if not all tests will allow the use of a calculator, so you can just do all the cal...

nolansheow3G

I would also try using videos on Youtube. I used Youtube for the majority of AP Chem and there are a lot of quality tutorials online - many include practice problems. The textbook has some tricky wording on some of the problems so if you've never seen a certain type of problem (like limiting reactan...

nolansheow3G

Our TA told us that if he was grading (which he is) he would not mark us off. However, he said that if we keep the calculations running in our calculator and round at the very end, our answer should match the answer key.

nolansheow3G

Will we be allowed to use graphing calculators? Or will I have to go out and buy a scientific calculator?

nolansheow3G

Will homework always be due on Friday during the lecture? Or will we switch to turning in HW to the TA during our discussion period? Just wondering because what if we have to turn in homework that wasn't covered yet (in case our lecture is after our discussion period).

CHEMISTRY COMMUNITY

Search found 30 matches

Re: Acids

Neutral Ligand

Re: OH- vs -OH

Biological Importance

Re: Identifying the difference

Re: Zinc Nitrate

Re: Bronsted Acids and Bases

Re: Donating H protons

Re: Electronegativity and Acidity

Re: VSEPR Shapes

Re: Molecular Shape

Re: VSEPR Model

Re: Strength of Bonds

Re: induced-dipole

Re: Covalent vs Hydrogen bond in H20

How many valence electrons?

Electron Affinity

The Number of Valence Electrons in Transition Metals

Re: octets

Re: Valence Electrons

Re: Valence Electrons

Re: Periodic Table Trends

Nodes of F Orbital

The PhotoElectric Effect

Re: Test 1 and Future Tests

Re: Rounding Using Significant Figures

Re: Studying techniques

Re: Problem F.1b

Re: Molar Masses

Re: Homework Questions [ENDORSED]