CHEMISTRY COMMUNITY

Sisi Li 1F

There's a page in the textbook that gives you a pretty comprehensive step by step of the process! In the 6th edition it's on page 741. I would also recommend watching some youtube videos on it, if you need some walk through of examples.

Sisi Li 1F

They are incredibly reactive- Alkali metals form 1+ ions and Alkaline Earth Metals form 2+ ions. As a result, they react strongly with water to form hydroxides

Sisi Li 1F

It's very VERY important to categorize sigma/pi bonds-- it helps us determine hybridization in our homework problems. It can also help determine the shapes of molecules. It's a crucial topic that we learn in the syllabus that will also be covered on the final

Sisi Li 1F

The Bronsted Acids and Bases can be restrictive as it focuses primarily on acids and bases acting as proton donors and acceptors, and in certain conditions this theory doesn't fit. The Lewis Acids and Bases alternatively looks at electrons which are donated/accepted. This helps predict a wider varie...

Sisi Li 1F

This was on test 2-- telling which bonds are more ionic and which are more covalent. For the bonds F-CL and P-O, they were so similar so it was tough to tell which one was more ionic. How can I reason through this, and other similar problems such as determining elements that are diagonal to each oth...

Sisi Li 1F

Molecular shape only considers the bonding pairs of a molecule. When there are lone pairs, you look at the geometry, or electron arrangement.

Sisi Li 1F

The shaded in triangle simply means that the electron is pointing towards you, while the dashed triangle means it's angled away. For the final, I wouldn't worry about having to know about this.

Sisi Li 1F

For iron, when it has a negative charge, the name becomes ferrate- this is the latin term.

Sisi Li 1F

Not the specific bond length, but know which bonds will result in shorter bonds and which results in longer bonds, and how that affects bond strength.

Sisi Li 1F

Dipoles are polar unless they cancel out in elements such as CCl4. Hydrogen bonding is a type of dipole-dipole interaction that occurs when F, O, C, and N are bonded to a hydrogen.

Sisi Li 1F

Intramolecular- within the compound, like ionic and covalent bonding
Intermolecular- with other compounds, such as dipole-dipole, hydrogen, london forces, etc.

Sisi Li 1F

Yes, you'd have to predict angles such as 109.5, 90, and 180. For elements in which areas of electron density are lone pairs instead of bonding pairs, the angles will change, but you won't need to know the exact angle, just know whether it's greater or less than the known angles. For example, a tetr...

Sisi Li 1F

Lewis acids are electron acceptors, they usually have an unfilled valence and will accept electron pairs from Lewis bases, which are electron donors that give away electron pairs.

Sisi Li 1F

Dipole moments occur wherever there is an unequal sharing of electrons, which makes the compound polar. If you look at the elements and see that they have different electronegativities, then electrons will be unequally shared. The element with the greater electronegativity will pull electrons toward...

Sisi Li 1F

Our homework for ch 3 covers electron configuration of ions, but the outline doesn't include that in the list of things to know. I'm wondering if we would still be tested on that since it was already covered in the midterm.

I posted this on the wrong forum so I'm reposting on the right one :'(

Sisi Li 1F

In lecture, Dr Lavelle talked about how to determine ionic and covalent bonds with electronegativity differences. He said that if the difference is between 2 and 1.5, then we need to look at the periodic table and see if the compound is a salt. Can someone further explain this?

Sisi Li 1F

Polarizing power is how much a cation distorts a polarizable anion. The charge of the cation causes the electron cloud of the anion to distort as it's attracted to the cation. At first, Lavelle made a distinction between covalent and ionic bonds because covalent bonds creates compounds whereas ionic...

Sisi Li 1F

I don't think the order of each element matters, just make sure that the formal charge matches with the charge given and you should be fine

Sisi Li 1F

I'd say you should show your formal charge calculations, just to show that you know a certain lewis structure is correct. Could depend on the TA though.

Sisi Li 1F

Prioritize valence electrons first, then look at the formal charge

Sisi Li 1F

Covalent bond creates compounds because the electrons are being shared to fill the octet, whereas in ionic bonds, ions are created as electrons donate/accept electrons to fill their octet

Sisi Li 1F

The vacuum essentially prevents other elements that are in the air from interacting with the experiment, which would throw off the results

Sisi Li 1F

In the context of this class, it should always be treated as a constant.

Sisi Li 1F

We use hydrogen because it has 1 electron, so it's must easier to study the quantum world because when there are multiple electrons it complicates things

Sisi Li 1F

You can use E=hv, or combine this with lamba=c/v to get E=hc/lambda

Sisi Li 1F

I believe metals are the only elements that donate electrons when excited, whereas nonmetals hold on to their electrons more. Although I don't think that is too important to know for the midterm

Sisi Li 1F

E is the energy of the photon. The work function, on the other hand, would give you the energy needed to remove an electron.

Sisi Li 1F

Decimal points will tell you how precise a number we are measuring. Looking at the number 100, you don't really know for sure whether 100 is an estimate or not- perhaps it was obtained by rounding up or down from a different number, but you don't really know for sure. On the other hand, 100. tells y...

Sisi Li 1F

On the solution manual (6th edition), there's a Calcium in the equation. Why is that? It is also unclear to me why they subtracted 34.02 g/mol from the total molar mass of the metal.

Sisi Li 1F

Basically temperature can't drop further than 0 Kelvin, it's the lowest limit.

Sisi Li 1F

It seems that because most of our problems are given in terms of grams, yields will also be in grams

Sisi Li 1F

I understand why using grams is ideal, but it's just the fact that kg is the base unit part that isn't clear to me.

Sisi Li 1F

In lecture, Dr. Lavelle said that kilograms was used for the base unit for mass. However, when we do conversions, we always write the powers of 10 with respect to grams. Can anyone explain why that is? Or am I misunderstanding something?

Sisi Li 1F

In lecture, Dr. Lavelle said that all stoichiometric coefficients must be the lowest whole number, so I imagine you would be docked points for leaving any coefficients in fractions.

CHEMISTRY COMMUNITY

Search found 34 matches

Re: Formula from Name

Re: Alkali Metals and Alkaline Earth Metals

Re: Importance of Sigma/Pi Bonds

Re: Bronsted and Lewis Acids and Bases

How to determine which bond is more covalent?

Re: Geometry vs molecular shape

Re: Molecular shape

Re: Fe------ferrate? [ENDORSED]

Re: Bond lengths [ENDORSED]

Re: Dipoles

Re: Inter and Intra

Re: Bond Angles

Re: Lewis Acids and Bases

Re: Polar v. Nonpolar

Is test 2 going to cover electron configuration for ions?

What to do if electronegativity difference is between 1.5 and 2? [ENDORSED]

Re: Polarizing Power [ENDORSED]

Re: Drawing lewis structures

Re: Formal Charge

Re: Which do you prioritize first

Re: Difference Between Ionic and Covalent

Re: Photo electric effect

Re: Speed of Light

Re: Class lecture

Re: Energy of photon [ENDORSED]

Re: Photo electric diagram

Re: E=hv [ENDORSED]

Re: Determining sig figs

Homework E.15 Solutions

Re: Use of Kelvin

Re: Theoretical/Actual Yield

Re: Can someone explain why we use kg for mass as the base unit?

Can someone explain why we use kg for mass as the base unit?

Re: Balancing Equations [ENDORSED]