CHEMISTRY COMMUNITY

Dakota Walker 1L

The rule is atom with lone pair - spacer atom - spacer atom - atom with lone pair. In CO3- this rule allows for only 2 bonds, and for C2O4, the same applies since you must have atoms in between.

Dakota Walker 1L

How are you supposed to compare strength of bases?
I know for acids you look at size and charge dispersion, what would you use for bases?

Dakota Walker 1L

I think the third lone pair can be found on the third nitrogen (the NH).

Dakota Walker 1L

Water can act as an acid or a base, if it is mixed with an acid, for example HCl +H2O then it will act as a base and form H3O+ and Cl-. If water is mixed with a base such as NH3 +H2O then it will act as an acid and donate a proton forming OH- and NH4+.

Dakota Walker 1L

Is there a difference between chelates and polydentate molecules?
If so how would you define each of them?

Dakota Walker 1L

Do we need to know specific examples and how they work for the final?
If so does anyone know which specific molecules we need to memorize?

Dakota Walker 1L

Can someone summarize the general rules for naming we will need for the final?
I don't understand what we do and don't have to memorize/know.

Dakota Walker 1L

Lewis acids accept electrons and lewis bases donate electrons.
Bronsted acids donate protons and bronsted bases accept protons.

Dakota Walker 1L

A bronsted base is a proton accepter while a bronsted acid is a proton donor, lewis acids and bases are the same they are just described differently where a lewis acid accepts electrons and a lewis base donates electrons. Arrhenius refers to acids and bases by OH- and H+ concentration so an acid put...

Dakota Walker 1L

If you were to include cis or trans in the naming would this just come at the front of the entire name?

Dakota Walker 1L

Yes solids have the strongest intermolecular forces because molecules are interacting so much that they are stuck together in solid form instead of bouncing off each other and moving far away in gas form.

Dakota Walker 1L

Can someone explain any general rules about using pi and sigma bonds? I understand how they overlap either end to end or sideways but do you have to draw out the entire 3D structure to figure this out? Or is there a rule deciding how many pi/sigma bonds are in molecules?

Dakota Walker 1L

Square pyramidal shapes have slightly less than 90 degree angles.

Dakota Walker 1L

There should only be double bonds on 2 of the Oxygen atoms!

Dakota Walker 1L

Linear models can either have no lone pairs, or 3 or 4 sets of lone pairs. When the 3 or 4 sets of lone pairs are in the same plane they do not bend the bonded atoms and therefore the overall molecule can still have a linear structure.

Dakota Walker 1L

This Question is: Predict the shapes and estimate the bond angles of (a) the thiosulfate ion, S2O3-2; (b) (CH3)2Be; (c) BH2- ; (d) SnCl2. Does anyone know how you would predict the shape of B?? (CH3)2Be has so many connections should we only predict the shape of the middle atom? Would this be linear...

Dakota Walker 1L

Yes, 2 lone electrons will create a balloon of repulsion and push the bonded electrons away from them, because they take up more space compared to bonded electrons.

Dakota Walker 1L

There will be london forces for all molecules, dipole-dipole forces for polar molecules where there is a difference in electronegativity between the atoms or a lone pair on the central atom, there are hydrogen bonds found between H and O, F or N, and there could be ionic bonds between atoms that giv...

Dakota Walker 1L

I think AsF3 is a polar molecule because it has a lone pair on the central atom, for this reason it will have a higher boiling point than the non-polar AsF5 molecule.

Dakota Walker 1L

When googling information about SO2 I found that it was bent, polar and has dipole-dipole interactions. Does anyone know if this is true? And if it is, why is the molecule bent?

Dakota Walker 1L

We're supposed to do the end of chemical bonds and not the start of molecular structure/shape?

Dakota Walker 1L

Are we doing homework this week on Molecular shape, or still on bonding?

Dakota Walker 1L

Highly polarized means that a bond is getting closer to becoming ionic because it has a large difference in its atom charges, and one is pulling the electrons a lot more closer than the other.

Dakota Walker 1L

Electronegativies will be given if we need to calculate them, otherwise we could just compare them based on periodic trends. The gray area describes polar bonds which I don't think are covered on this midterm.

Dakota Walker 1L

What is the orbital angular momentum equation?

Dakota Walker 1L

I think debroglis is used if you want to find wave length and E=hv is used if you have frequency or energy and want to find the missing variable.

Dakota Walker 1L

You need to find the configurations for the elements with 2 less electrons (2+) so for a it would be the ion that matches [Ar]3d74s2, and for b) it would be the ion that goes with [Ar]3d64s2.

Dakota Walker 1L

This problem asks you to draw lewis structures for:
a) periodate ion, b) hydrogen phosphate ion, c) chloric acid etc.

I was wondering if we need to know what a "periodate ion" is for our midterm/final or if the IO4- would be given?

Dakota Walker 1L

When drawing lewis structures do we need to calculate all formal charge options in order to decide how the structure should be drawn? Or can you just draw it based on electrons and guess on the double bond.

Dakota Walker 1L

Yes! The molecule will have an overall charge of -1, so each atom will have its own charge (likely -2 and +1) allowing the whole molecule to add to -1.

Dakota Walker 1L

When drawing lewis structures on tests do you need to angle the bonds in the correct ways or would we get full points for drawing our best guess?

Dakota Walker 1L

Which M2+ ions are predicted to have the following ground state configurations? [Ar]3d6, [Kr]4d9, [Ar]3d10 etc.
I don't understand what this question is asking, does anyone know how to go about answering it / what the answer is?

Dakota Walker 1L

Which of the following species are radicals? a) NO2-, b) CH3, c) OH, d) HOCO.
Can someone explain how to do this question? And explain what a radical is?

Dakota Walker 1L

Does anyone know what topics are on the midterm?
Is it review of chem, quantum world and bond lengths? Or are bond lengths not on it because we are still reviewing them?

Dakota Walker 1L

x y z differentiate the spaces electons can go within the P orbital because it has 3 spaces for paired electrons, for the D orbital the letters would be different/longer - I would guess u w x y z but am unsure.

Dakota Walker 1L

The lettered orbitals are what matters in context, the number "4" for example in 4s or 4p is arbitrary.

Dakota Walker 1L

You only look at the lettered sub-shells not the number before, so S will always have 1, P has 3, D has 5 and F has 7 (you know this by drawing out the orbitals to place paired electrons in).

Dakota Walker 1L

Does anyone know why the uncertainty in the equation wasn't 10 because 5+5 is 10?

Dakota Walker 1L

What does Zeffe mean in this context?

Dakota Walker 1L

Homework problem 1B.3. asks for the protons, neutrons and electrons in Boron-11. I answered that the protons would be 5 (because of the atomic number), the electrons would be 5 to match this, and the neutrons would be 6 so that the mass would add up to 11. Is this right?

Dakota Walker 1L

How do we know what homework problems to do each week? Like should we be doing quantum world or chemical bond problems for week 4?

Dakota Walker 1L

also how do you convert the 10^-12 answer into nm

Dakota Walker 1L

How do you get the value for c in this equation?

Dakota Walker 1L

When he went over the 2 models of electrons orbiting a nucleus, was the only thing you were supposed to take away from that the fact that an open line (electron path) would not work?
I feel like i missed the concept we were meant to learn here does anyone know what it is?

Dakota Walker 1L

Because hydrogen has one electron for every H atom, the number of excited electrons will be equal to the number of excited hydrogen particles, which in this case is 1 million.

Dakota Walker 1L

The 4s orbital is lower in energy therefore it is filled before the higher energy 3d orbital. If you draw it out, you can see that 4s is below 3d and thus would fill up sooner.

Dakota Walker 1L

a)The energy of an electron does increase as it gets further away from the nucleus, therefore as it moves from the 1s to the 2p orbital it would experience an energy increase.
b)The value of n also increases as an electron moves away from the nucleus (it goes from 1n to 2n etc).

Dakota Walker 1L

When calculating properties of electrons are we supposed to use equations that include wavelengths, even though an electron does have properties that make it behave like a photon?

Dakota Walker 1L

How do you create a new post on this website?
I have figured out how to create a completely new topic, which I am doing right now, and how to reply to previously answered questions, but how do you regularly create a new post/question under a previously existing topic?

Dakota Walker 1L

If you wanted to convert, for example, 400nm to angstroms, how would you do this?
Angstroms are 10^-10m and nm are 1*10^-9m.
Would you have to convert nm to m first, or how generally would you do this?

Dakota Walker 1L

I still don't understand why this isn't a dilution when a 75mL solution was created at first, then this same solution was diluted to get a 125mL solution. In what way would a dilution problem be written differently?

Dakota Walker 1L

In the post module test there was a question asking the following: 339.20 g of Cobalt metal is reacted with Fluorine gas to produce a compound with a mass of 996.08 grams. What is the empirical formula of this new compound? I was wondering if you always apply the law of conservation of mass to these...

Dakota Walker 1L

Do we need to memorize all the units and conversions we learnt in class (deci, nano, etc) for the test this week or the midterms in class?

Dakota Walker 1L

For Cu the charge would be -2 because you pull up the number from the bottom of the opposite element which in this case is (NO3)2, making the charge of Cu -2.

Dakota Walker 1L

Fe3Br8 + 4Na2CO3 -> 8NaBr + 2CO2 + 2Fe3O4

Dakota Walker 1L

I believe you need a balanced chemical equation to solve this problem? But I am not sure how to exactly calculate the molarity of ions if we don't have their molar ratios.

Dakota Walker 1L

Yes, if you are trying to find the molar mass of an isotope you can ignore the average atomic mass and multiply the atomic mass of the isotope by avogadro's number.

Dakota Walker 1L

Because there are so many different significant figures that can be used for molar masses, for example Hydrogen could be 1.01, 1.008, etc, how does this work with significant figures? If you use 1.01 can you only use 2 decimal places in your final answer?

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