CHEMISTRY COMMUNITY

Rachel Dang 1H

Why did the attacking army use acid?
To neutralize the enemy’s base.

Rachel Dang 1H

What’s Iron Man’s favorite amusement park ride?
The ferrous wheel.

Rachel Dang 1H

Did you hear about oxygen’s date with potassium?
It went OK.

Rachel Dang 1H

Two chemists walk into a bar.
One says, “I’ll have an ‎H2O.” The other says, “I’ll have an ‎H2O, too.” The second chemist dies.

Rachel Dang 1H

If they give you a salt as the product, I think we are supposed to identify the cation and anion and assume that the other product was liquid water and work from there.

Rachel Dang 1H

The difference is in the definition of what each type considers an acid or base.

Rachel Dang 1H

This is a good question, can someone answer it?

Rachel Dang 1H

I would say to memorize the seven strong acids and the reasoning why they are strong acids.

Rachel Dang 1H

I believe these are the same thing. If anyone knows otherwise please correct me!

Rachel Dang 1H

For exams just look at the outlines on Professor Lavelle's website, they detail key concepts that we should know for the tests

Rachel Dang 1H

There really isn't another way, the best thing to do is just memorize them because the AXE formula tells you what shape the molecule is.

Rachel Dang 1H

Professor Lavelle mentioned in lecture that like other said above a molecule can always be distorted. For example CCl 4 is nonpolar since all of the dipole moments cancel out and is unlikely to be distorted however for a similar molecule that does have an overall dipole moment due to having two bond...

Rachel Dang 1H

An induced dipole is when a molecule that is usually non polar has become temporarily induced to have a dipole by surrounding molecules. I believe a dipole moment is just when a molecule itself has a dipole due the electronegativity of its constituent atoms. A dipole-dipole interaction is when any p...

Rachel Dang 1H

We will most likely have to memorize the names of the shapes. As for bond angles if the central atom has no lone pairs I believe that we can calculate bond angle by dividing 360 the number of central atoms if it's in one plane but other wise we'll have to at the very least know them roughly. And if ...

Rachel Dang 1H

We can calculate them using VSEPR if the central atom has no lone pairs by dividing 360 degrees by how many atoms are bonded to the central atom. However we cannot use this method when they are are lone pairs since VSEPR doesn't account for the distortion that happens when the lone pair and bonded e...

Rachel Dang 1H

You can calculate polar and non-polar with electronegativity levels since that will reveal whether an electron is shared unequally or not. For the most part diatomic molecules are non-polar.

Rachel Dang 1H

Elements like Cr and Cu (and the ones in the same columns) are different in that half full shells and half shells are more stable than not, making their electron configuration [Ar]3d^5 4s^1 and [Ar]3d^10 4s^1. But the concepts described above still are true in that electrons from the outmost energy ...

Rachel Dang 1H

When we calculate electronegativity, values will be given to us either in the form of a periodic table with those values listed or something similar.

Rachel Dang 1H

London forces are instantaneous or temporary dipoles and it also induces surrounding atoms into having temporary dipoles as well. These are the smallest and individually very weak but actually are the most significant contributor to IMF for most molecules

Rachel Dang 1H

I don't know if there is a rule of thumb per say but generally atoms want to achieve a full valence shell, whether that be by losing or gaining through bonds. So rather than a general number I believe it depends on its position in the periodic table and how many valence electrons it has.

Rachel Dang 1H

We lose the electrons from the s and p subshells first because if you look at the configuration, those subshells are within the 6th and outermost shell. The f and d subshells are within the 4th and 5th and closer to the nucleus and harder to "steal" in comparison to the electrons in the 6t...

Rachel Dang 1H

Yup, whenever doing calculations involving units make sure you have ones that allow you to cancel out what you don't need while ending up with the correct units for your answer. So yes in that case you would need mass in kg.

Rachel Dang 1H

Blackbody radiation should not be on the test next week, the material that we have covered including today's lecture will be though.

Rachel Dang 1H

Don't know if this is how it's defined in this class but you can think of it as what happens when a massive bulky object that absorbs all radiation and then emits its own form of radiation. One example would be like a burner of an oven that heats up and changes color as it gets hotter from black to ...

Rachel Dang 1H

States of matter will come into play later when we go into topics like entropy and intramolecular forces but for now we don't really need to worry about them when writing chemical equations.

Rachel Dang 1H

Yes we can use the that formula whenever we are given 3 of the 4 values or information to find those values.

Rachel Dang 1H

Typically your answer should be in the same units that it was given in the problem unless stated otherwise but Lavelle is okay with either as long as it's the right answer.

Rachel Dang 1H

Theoretical yield is the value you get if your reaction were to react to completion in an ideal world. However during experimentation there are a lot of things that can go wrong like residue on glassware, or side reactions that either take away from your original reaction or result in an impure prod...

Rachel Dang 1H

States of matter can come into play when you're writing net ionic equations like in problem M9. They'll also come into play when looking at solubility and what ions are actually interacting with each other in a precipitation reaction or why a solid is a solid and not another state of matter at a cer...

Rachel Dang 1H

The molarity used in part B is found by solving part A. If you've done that, your answer should be the molarity used. The 100. ml just tells you how much volume you have, and doesn't change the molarity of the solution. You use this 100. ml value in a stoichiometric calculation to find how many mole...

Rachel Dang 1H

If you round in between your answer could either be erroneously high or low (depending on whether or not you round up or down) and be off, so it's best to wait until the very end and keep all your number in your calculator if you can.

Rachel Dang 1H

Rather than just the conversion from pm to m, I think we need to be aware and know of all the different prefixes and what they mean since it will be easier to perform conversions like that when doing calculations.

CHEMISTRY COMMUNITY

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Re: Post All Chemistry Jokes Here

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Re: Neutralization Reactions

Re: Identifying the difference

Re: Identifying Lewis Acids and Bases

Re: Memorize strong and weak acids and bases?

Re: Difference between hybridization and hybrid orbitals

Re: Exam 3 Topics [ENDORSED]

Re: AXE formula

Re: Tetrahedral shape

Re: Dipole Moments [ENDORSED]

Re: Bond Angles

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Re: Polar and Nonpolar

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Re: How To....

Re: Formula M1V1=M2V2 [ENDORSED]

Re: Changing Units

Re: Theoretical vs Actual Yield

Re: States of Matter

Re: L.37 part B

Re: Sig Figs... when to round?

Re: pm to m