CHEMISTRY COMMUNITY

Erin Li 1K

I don't trust atoms...I heard they make up everything.

Erin Li 1K

we do not need to know how to calculate electronegativities. However, the trend is that EN increases towards an upwards diagonal to the right. it decreases down a column and increases across a row.

Erin Li 1K

Differences in electronegavity determine the ionic character. the higher the difference in electronegativity, the greater the ionic character

Erin Li 1K

a sigma bond is one single covalent bond
so for single, double, and triple bonds,
a single bond=1 sigma bond
a double bond=1 sigma bond+1 pi bond
a triple bond=1 sigma bond+2 pi bonds

Erin Li 1K

No, resonance structures do not have to have the same formal charge for each element. however, the overall formal charge should be the same. For example, if it was No3-, overall it should have a -1 formal charge for the -

Erin Li 1K

VSEPR stands for valence shell electron pair repulsion and it achieves the geometry that has the least electron repulsion

Erin Li 1K

a sigma bond is when there is one single covalent bond
however, double bonds and triple bonds also have a sigma bond

Erin Li 1K

atoms are most stable when they have eight electrons. However, there are exceptions to this like hydrogen which only has one electron.

Erin Li 1K

you would have to calculate the formal charge by the equation:
formal charge = number of valence - lone electrons - (shared electrons/2)

Erin Li 1K

Hydrogen really only has one electron even when bonding and there is no exception to that, so when Hydrogen has only one electron (which is always the case) it has a formal charge of 0

Erin Li 1K

you calculate formal charge by using the equation
number of valence electrons - number of lone electrons and number of bonds

Erin Li 1K

greater ionic character means greater difference in electronegativity

Erin Li 1K

Will VSEPR be on test three? or is it just lewis structures?

Erin Li 1K

No this will not be provided

Erin Li 1K

it's E(n) = -(hR)/nfinal^2 -(hR)/ninitial^2
and for frequency it is = R [(1/nfinal^2) - (1/ninitial^2)]

Erin Li 1K

If a certain frequency is not ejecting electrons. Does increasing frequency eject electrons?
Also what increases the number of electrons ejected?

Erin Li 1K

What are the differences between these three series and how do I tell the difference between them?

For example, in problem 1.13 problem b, why is the answer Balmer?

Erin Li 1K

you find the moles of each and compare it to the ratios in the chemical equation
or you can use both and the balanced chemical equation see which one produces less product

Erin Li 1K

I get overwhelmed and intimidated when reading the textbook too, so I would recommend only doing so when you have your full attention to the book and no other distractions.

Erin Li 1K

A covalent bond would just be between two nonmetals while an ionic bond is between a nonmetal and a metal! just look at the two elements in the chemical equation

Erin Li 1K

I need help on the following problem (G13 in the textbook): To prepare a fertilizer solution, a florist dilutes 1.0 L of 0.20 m NH4NO3(aq) by adding 3.0 L of water. The florist then adds 100. mL of the diluted solution to each plant. How many moles of nitrogen atoms will each plant receive? Solve th...

Erin Li 1K

with the equation 1/2 times mv^2, you use the KJ/mol to covert the mols to kg for the m part in the equation. The m stands for mass, so you need to convert the mols to kg. Then, Kinetic energy is measure in Joules which is already used in the equation, so some units should cancel out.

Erin Li 1K

No; based on the law of conservation of mass, the amount of products is equal to the mass of the reactants since this mass is not created nor destroyed in chemical reactions. They are just bonded differently.

Erin Li 1K

This means that there are 6N and and only 1 Mn. You would have to take into consideration both elements when balancing the equations. You would generally balance the one that is by itself on the other side last or balance the one first that is easiest to balance corresponding to the other side.

Erin Li 1K

I think either is fine, but generally in chemistry, scientific notation is used. However, Lavelle did mention that significant figures do not matter in this course.

Erin Li 1K

I agree. I also think it's arbitrary. None of them technically point upward or to the right, it is just a matter of how they are viewed and at what angles.

Erin Li 1K

Most often if it is talking about mass then you would revert back to kg since it is one of the standard units. The standard units are kg, m, and sec which is what are normally used.

Erin Li 1K

No. Someone asked Lavelle if significant figures matter on tests, and he said no.

Erin Li 1K

No. We do not need memorize the periodic table components for the first exam! I'm sure they will provide us with needed information and periodic table if necessary.

Erin Li 1K

They are just posted for extra help on exam materials and used for guidance!

CHEMISTRY COMMUNITY

Search found 30 matches

Re: Post All Chemistry Jokes Here

Re: Calculating electronegativity

Re: Test 3. Question 7.

Re: Detail of Bonds

Re: Resonance Structures

Re: VSEPR

Re: σ bonds

Re: Octet rule

Re: lowest energy & most stable Lewis structures

Re: H Formal Charge

Re: Formal charge?

Re: ionic character

VSEPR on test 3?

Re: Information Provided on Exam

Re: Rydberg Formula for Atomic Hydrogen [ENDORSED]

Frequency on Photoelectric Effect

Lyman vs. Balmer vs. Paschen vs. Brackett?

Re: moles + limiting reactant

Re: Reading the textbook

Re: Types of Bonds

Problem G13

Re: Module Question 27.A

Re: Mass of Products VS. Mass of Reactants- Class Assessment

Re: Subscripts [ENDORSED]

Re: Scientific notation [ENDORSED]

Re: Electromagnetic Field [ENDORSED]

Re: Units for Answer

Re: Sig Figs [ENDORSED]

Re: Periodic Table Memorization [ENDORSED]

Re: Modules