CHEMISTRY COMMUNITY

AnvitaaAnandkumar_1B

I think this compound is a lewis base as Sulphur atom has lone pairs on it and therefore, the compound can act as an electron pair donor.

AnvitaaAnandkumar_1B

Double bonds and triple bonds also count as only one region of electron density.

AnvitaaAnandkumar_1B

How many hydronium ions are present at any moment in 100. mL of pure water at 25 C?

AnvitaaAnandkumar_1B

Because Bronsted acids are defined to be the molecules to that donate a proton (H atom), NH4+ would be the Bronsted acid here as it is the one that donated a proton to HCO3- and became NH3. Lewis acids are defined to be the lone pair acceptors so NH4+ would be considered a Lewis acid since it is po...

AnvitaaAnandkumar_1B

(a)Identify the Brønsted acids and bases in both reactants and products in the proton transfer equilibrium HCO3-(aq) + NH4+(aq) ---> H2CO3(aq) + NH3(aq).
(b) Which species (not necessarily shown explicitly) are Lewis acids and which are Lewis bases?

AnvitaaAnandkumar_1B

What is (a) the conjugate acid of H2O; (b) the conjugate base of NH3?

AnvitaaAnandkumar_1B

I think this has to do with things like Ligand Field Theory and Crystal Field splitting, which we aren't going to be discussing in class

AnvitaaAnandkumar_1B

When excess silver nitrate is added to 0.0010 mol CrCl3.6H2O in aqueous solution, 0.0030 mol AgCl is formed. Which hydrate isomer is present?

AnvitaaAnandkumar_1B

(a) Name the compound [CoBr(NH3)5]SO4.
(b) Write the formula of tetraamminediaquachromium(III) bromide.

AnvitaaAnandkumar_1B

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.

AnvitaaAnandkumar_1B

I think there are certain elements with coordination number 2 or 3 (CO3 2- has 3) but it's not very common.

AnvitaaAnandkumar_1B

So the coordination sphere is essentially the entire coordination part of a compound. It includes the central metal atom and all the ligands that are connected to it.

AnvitaaAnandkumar_1B

I think the TAs said you would be able to see it at the end of the quarter.

AnvitaaAnandkumar_1B

The coordintion number is correlation to the central metal atom as it speaks to how many ligands (or points of connection for bi/tridentate ligands) can connect to the central metal atom.

AnvitaaAnandkumar_1B

The breaking of the octet rule occurs primarily when the element has empty d orbitals to use for bonding.
This aids in creating the lowest formal charge for the molecule as a whole, but is not directly correlated to making the formal charge for that particular atom zero.

AnvitaaAnandkumar_1B

In general, the molecule doesn't have a net dipole when the orientation of species around the molecule is symmetrical, resulting in a cancelling of dipole moments. In the case of a tetrahedral geometry, the molecule only doesn't have dipole moment when all four species surrounding the central atom a...

AnvitaaAnandkumar_1B

The direction of the arrow indicates the direction of the dipole. So, dipole arrows should be drawn from positive to negative. That way, the direction the arrow points represents where an electron is more likely to be found.

AnvitaaAnandkumar_1B

An ion-dipole interaction is the result of an electrostatic interaction between a charged ion and a molecule that has a dipole. It is an attractive force that is commonly found in solutions, especially ionic compounds dissolved in polar liquids.

AnvitaaAnandkumar_1B

The boiling point of a molecule corresponds to the extent of Hydrogen bonding it undergoes - the greater the amount or strength of the hydrogen bonds, the higher the boiling point.

AnvitaaAnandkumar_1B

Q. How did the molecular spy introduce himself?
A. My name is Bond.. Covalent Bond.

AnvitaaAnandkumar_1B

VSEPR jokes

AnvitaaAnandkumar_1B

The bonding pair shared in a bond lies further from the atom than a nonbonding pair of that atom which is held close to its positively charged nucleus. Consequently, lone pairs are closer to each other than any other combination of pairs (lone pair-bonding pair and bonding pair-bonding pair), and th...

AnvitaaAnandkumar_1B

Electrons in an atom repel each other due to the fact that they have the same charge The strength of repulsion is such that lone pair- lone pair repulsions > Lone pair - bond pair repulsions > bond pair - bond pair repulsions Thus, by spreading the electrons and ensuring they're far away from each o...

AnvitaaAnandkumar_1B

Old Chemist One-Liner:
Old chemists never die, they just stop reacting

AnvitaaAnandkumar_1B

I first calculated the energy released per photon - which you get by using E = hc/lambda = 3.14 x 10^(-21) I then calculated the total energy released in a second by multiplying the energy per photon (which I found) with the number of photons produced. I got this value to be 7.536 J. Since the quest...

AnvitaaAnandkumar_1B

Ba is in the 2nd period of the periodic table i.e it has high metallic character and therefore very low electronegativity while Br is in the 17th period and therefore has high electronegativity. Due to this large difference, the bond is primarily ionic. In addition, on the test, you could also simpl...

AnvitaaAnandkumar_1B

We don't need to specify the orientation of the orbitals.
So we just need to write p^3

AnvitaaAnandkumar_1B

A covalent bond yelled at an ionic bond - Didn't anyone ever teach you how to share??

AnvitaaAnandkumar_1B

Which of the following increase when the electron in a hydrogen atom undergoes a transition from the 1s-orbital to a 2p-orbital? (a) Energy of the electron. (b) Value of n. (c) Value of l. (d) Radius of the atom.

AnvitaaAnandkumar_1B

By determining the difference in electronegativity between the elements.

AnvitaaAnandkumar_1B

The central atom is usually the one with the lowest electronegativity or the least numerous element.

AnvitaaAnandkumar_1B

Q: What emotional disorder does a gas chromatograph suffer from?
A: Separation anxiety.

AnvitaaAnandkumar_1B

Yes, pretty much If the difference in electronegativities is greater than 2, the bond will be ionic If the difference in electronegativities is less than 1.5, the bond will be covalent for elements with difference in electronegativity between 1.5 and 2, the compounds will need to be taken on an indi...

AnvitaaAnandkumar_1B

Write the electron configurations of (a) the manganese(II) ion and (b) the
lead(IV) ion.

AnvitaaAnandkumar_1B

Electron affinity describes the amount of energy released or spent when an electron is added to a neutral atom or molecule in the gaseous state to form a negative ion. It therefore tells us about the ease with which an electron can be added to a gaseous molecule. The general trend for electron affin...

AnvitaaAnandkumar_1B

I think this question can be solved by looking at a periodic table. (a) [Ar] 3d6 : No. of electrons in M ^+3 state = 18 + 6 = 24 Therefore no. of electrons in M = 24 + 3 = 27 Therefore M is Co (b) [Ar] 3d5 : No. of electrons in M^+3 state = 18 + 5 = 23 Therefore no. of electrons in M = 23 + 3 = 26 T...

AnvitaaAnandkumar_1B

Hey! Is there any connection between the location of the nucleus and the nodal plane? Is the nucleus located on the nodal plane, since you cannot find an electron in the nucleus or the nodal plane? A nodal plane will generally include the position of the nucleus as, like you said, you cannot find a...

AnvitaaAnandkumar_1B

Shielding is essentially the reduction in the effect of the nuclear charge from the nucleus felt by electrons in outer orbitals because they are blocked or "shielded" from the nucleus by the electrons in the inner orbitals

AnvitaaAnandkumar_1B

How many unpaired electrons are predicted for the ground-state configuration of each of the following atoms: (a) Pb; (b) Ir; (c) Y; (d) Cd?

AnvitaaAnandkumar_1B

Write the ground-state configuration of an arsenic atom.

AnvitaaAnandkumar_1B

Nodal planes denote the areas in which the probability of finding electrons is zero.
Each orbital configuration (s,p,d and f) have different nodal planes.

AnvitaaAnandkumar_1B

Schrödinger and Heisenberg are driving down the motorway when a cop pulls them over. He walks up to the window and asks, "Sir, do you know how fast you were going?" Heisenberg replies, "No, but i know exactly where I was." The cop, thinking that such a weird response deserves fur...

AnvitaaAnandkumar_1B

For the second part of the question, what changes is the uncertainty in position, delta x. The range of the nuclear diameter is generally taken as 1.7 x 10^(-15) metres. Therefore, you substitute that value into the Heisenberg's indeterminacy equation and calculate the uncertainty in momentum You th...

AnvitaaAnandkumar_1B

Arrange the following types of photons of electromagnetic radiation in order of increasing frequency: visible light, radio waves, ultraviolet radiation, infrared radiation.

AnvitaaAnandkumar_1B

The police are monitoring an automobile of mass 2.0 t (1 t 5 103 kg) speeding along a highway. They are certain of the location of the vehicle only to within 1 m. What is the minimum uncertainty in the speed of the vehicle? Can you use as your defense the argument that the uncertainly principle prev...

AnvitaaAnandkumar_1B

Thank you!

AnvitaaAnandkumar_1B

Calculate the wavelength of a rifle bullet of mass 5.0 g traveling at twice the speed of sound (the speed of
sound is 331 m?s2 1).

AnvitaaAnandkumar_1B

A red giant is a late stage in the evolution of a star. The average wavelength maximum at 700. nm shows that a red giant cools as it dies. What is the surface temperature of a red giant?

AnvitaaAnandkumar_1B

What is the wavelength of the signal from a radio station transmitting at
98.4 MHz?

AnvitaaAnandkumar_1B

Q: What kind of test do chemistry students like best?
A: Mole-tiple choice.

AnvitaaAnandkumar_1B

To solve this we use the dilution law : M1V1 = M2V2. M1 = 0.20M . M2 = V1 = 1 l . V2 = 1 + 3 = 4 l Substituting in the equation, we get M2 = 0.05M Molarity = (No. of moles) divided by (volume in litres) Therefore, 0.05 = (n x 1000)/ 100 = 0.005 moles of NH4NO3 Each mole of NH4NO3 has 2 moles of N th...

AnvitaaAnandkumar_1B

Calculate the mass of oxalic acid needed to prepare 50.00 mL of 0.125 m C2H2O4(aq).

AnvitaaAnandkumar_1B

Dolomite is a mixed carbonate of calcium and magnesium. Calcium and magnesium carbonates both decompose upon heat- ing to produce the metal oxides (MgO and CaO) and carbon dioxide (CO2). If 5.12 g of residue consisting of MgO and CaO remains when 10.04 g of dolomite is heated until decomposition is ...

AnvitaaAnandkumar_1B

In the text under section E, in order to find the average molar mass for elements that have isotopes, they have first found the average atomic mass and then multiplied by Avogadro's constant to get the average molar mass. However, if in a question we are presented with the atomic mass, molar mass nu...

AnvitaaAnandkumar_1B

Thanks!

AnvitaaAnandkumar_1B

A double espresso contains 3.14 mol H2O. What is the number of H atoms present in the espresso?

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