CHEMISTRY COMMUNITY

Isabel Day 1D

What are the formulas we have to know for acid rain?

Isabel Day 1D

The Ba ion usually has a positive charge of +2 (Ba2+) because it becomes more stable when losing 2 electrons. OH- always has a negative charge. Therefore, 2 OH- are bonded to Ba2+ in order for the compound to be neutral.

Isabel Day 1D

Will all polydentate ligands be named with the prefixes bis, tris, tetrakis, even if they're acting as a monodentate ligands in certain situations?

Isabel Day 1D

You will use the De Broglie equation in most quantum questions when the question asks for either the momentum, frequency, or wavelength of an electron. If you given any 2 of these variables, you can find the other using wavelength=h/mv. You can also find the energy of an electron using this equation...

Isabel Day 1D

Yes, because acids have pH less than 7 and bases have pH greater than 7.

Isabel Day 1D

HW question 6D.11 (d) asks whether the solution of KBr has a pH greater than, equal to, or less than 7. Why is the aqueous solution of KBr equal to 7? How would I write a chemical equation to show this?

Isabel Day 1D

I'm pretty sure we can use abbreviations for (en) and (edta). I'm not sure about oxalato.

Isabel Day 1D

What does it mean when there's a 2 in front of the hybridization? For example, in question 17 of marshmallow many of the sigma bonds have C2sp2 or N2sp hybridizations.

Isabel Day 1D

Question J.23 asks to name the acid formed when (a) CO2 and (b) SO3 react with water. Should we know how to name acidic compounds? I don't remember learning this.

Isabel Day 1D

Why is "diaqua" in parentheses in sodium bisoxalato(diaqua)ferrate (III)?

Isabel Day 1D

When naming the complex ion (Fe(CN)6)4-, why is iron represented as "ferrate"? Is this just something I have to memorize?

Isabel Day 1D

Yes, anion ligands come before neutral ligands. If there's more than one anion or neutral ligand, they're written in alphabetical order.

Isabel Day 1D

I think this means that these topics won't be covered on exams.

Isabel Day 1D

This used to confuse me too. We know we're supposed to use Ca2+ and Mg2+ because these are the most common ions of these elements. Ca and Mg both have 2 valence electrons, so they often donate 2 electrons and become 2+ ions. The question asks for the ground state configuration of the ION and not the...

Isabel Day 1D

You can identify an amphoteric compound by seeing if it would be able to both accept and donate hydrogen atoms.

Isabel Day 1D

Is there a difference between complexes and coordination compounds? The textbook uses these 2 terms often and I'm wondering if the have the exact same meaning.

Isabel Day 1D

Can hybridization be done for atoms with shapes that aren't linear, trigonal planar, tetrahedral, trigonal bipyramidal, or octahedral? For example, can atoms with bent, seesaw, etc. shapes have a hybridization? If not, why?

Isabel Day 1D

This is what one of the TA's said: - Use VSEPR model to determine the shape of inorganic, organic, and small biological molecules, cations, and anions - Use bond dipole moments and shape to determine if a molecule is polar or non-polar - Use shape and polar or non-polar properties, identify intermol...

Isabel Day 1D

I don't understand the difference between equatorial and axial angles. If the repulsion between electrons is equal, why aren't all the angles equal in certain structures? (like trigonal bipyramidal)

Isabel Day 1D

Yes, a single electron counts as a region of electron density just as a lone pair would.

Isabel Day 1D

Question 2E.11 asks for the VSEPR model, shape, and formula for xenon trioxide. I know the formula is AX3E and the shape is trigonal pyramidal, but I don't understand why the bonds between xenon and oxygen are all double bonds in the structure. When I drew the structure, I found that there were 26 e...

Isabel Day 1D

How can you find the bond angles of molecules with lone pairs? Are they always smaller than the original angles?

Isabel Day 1D

How do antioxidants react with radicals? What does this look like on a chemical level?

Isabel Day 1D

Are incomplete octets common? How do we know if an atom can have an incomplete octet? I don't understand this concept.

Isabel Day 1D

The only exceptions are noble gases because they have a complete valence shell and don't tend to accept electrons.

Isabel Day 1D

Yes, I believe 12 is the limit.

Isabel Day 1D

Is there an easy way to find the number of valence electrons for transition metals on the periodic table? Is there some type of pattern, like with elements in the main groups?

Isabel Day 1D

Page 31 of the textbook explains how the highest energy level is 0, but I don't understand what this means. If 0 is the point when the electron is escaping from the nucleus, how could this be the highest energy level?

Isabel Day 1D

There's 2 equations we use for the photoelectric effect. E= hv (where E: photon energy, h: Planck's constant= 6.63x10^-34, and v= frequency) This equation can also be written as E= hc/wavelength (where c: speed of light= 3.00x10^8) We can use this equation if we're given (1) the energy of the photon...

Isabel Day 1D

The aufbau principle states that electrons will fill lower energy levels before moving to higher energy orbitals, but the rules are all related. The aufbau principle takes into account the Pauli exclusion principle and Hund's rule to explain the building-up of electron configuration. You could think...

Isabel Day 1D

Problem 1E.17 states: For each of the following ground-state atoms, predict the type of orbital from which an electron will be removed to form the +1 ion: (a) Ge; (b) Mn; (c) Ba I don't understand the answer to (b). The solutions manual says it's 4s, but I thought it was 3d because 3d is filled afte...

Isabel Day 1D

1E.3 asks (a) Write an expression for the total coulomb potential energy for a lithium atom. (b) What does each individual term represent? I'm not sure how to answer this question because I don't understand the coulomb potential energy expression. The textbook expression looks different than the one...

Isabel Day 1D

1B.27 states: A bowling ball of mass 8 kg is rolled down a bowling alley lane at 5.00+/-5.00 m.s^-1. What is the minimum uncertainty in its position. I understand how to solve this problem using Heisenberg's uncertainty equation, but I don't understand why delta V is 5.00 m.s^-1. Shouldn't it be 10 ...

Isabel Day 1D

I'm pretty sure the uncertainty is 10 mm.

Isabel Day 1D

I've noticed that in the De Broglie and Heisenberg uncertainty principle problems, we use kg as the basic unit for mass instead of g. This confused me at first because I thought we should always convert kilos to the base unit (grams, meters, etc.). Are kilograms always used as the base unit for thes...

Isabel Day 1D

I know electrons have wavelike properties, but do protons and neutrons have wavelike properties as well?

Isabel Day 1D

Question 35 on the module says: Calculate the wavelength of a 275 kg single-seat electric car traveling at a speed of 125 km.hr-1. Do electric cars have wavelike properties? I've done this problem many times and keep getting the wrong answer. I always get 1.57x10^-39. What am I doing wrong? This isn...

Isabel Day 1D

Some module and homework questions ask which region of the electromagnetic spectrum certain wavelengths or frequencies correspond too. Are we supposed to memorize the frequencies or wavelengths of each type of light?

Isabel Day 1D

I'm, having a hard time understanding how light can have both wave and particle properties. Do both of these properties exist at the same time? If anybody has a good visual way of thinking about it that would be super helpful.

Isabel Day 1D

The ejected electron is the electron that is released from the metallic surface. The UV radiation is the source of light that caused the ejection of the electron. In order to solve for the wavelength of the emitted electron, find the kinetic energy (KE=1/2mv^2) and use this energy in the equation E=...

Isabel Day 1D

Do electrons vary in mass or is it always the same?

Isabel Day 1D

If a problem gives me only the velocity of the ejected electron and the work function for the metal, how do I find the kinetic energy? I can't figure out how to do it without needing the mass of the electron or the frequency of the incoming photon. This is the problem: Light hits a sodium metal surf...

Isabel Day 1D

Why is calcium hydroxide written as Ca(OH)2 and not just CaOH? This comes up in problem H.7

Isabel Day 1D

Should we know how to name compounds at this point? I notice that a lot of question ask to write the chemical formula from the compound names and I’m just wondering if we should know how to do it the other way around.

Isabel Day 1D

Yes, your equation is balanced but it doesn’t represent the amount of reactants and products in the boxes. In the first box there are 4 H20 molecules and 2 SiH4 molecules. In the second box there are 2 SiO2 molecules and 8 H2 molecules. Therefore, the equation that’s both balanced and represents the...

Isabel Day 1D

The radius is used to find the denominator of the atoms. Then if you multiply the denominator by the amount of atoms, you find the length of the fiber.

Isabel Day 1D

What are formula units? Can a formula unit be the same thing as a molecule or atom? (E.21 and E.25 ask about this)

Isabel Day 1D

Question E.15 asks to find the molar mass of the sulfide of M(OH)2, but I don’t understand how to derive a sulfide from this molecule and I’m confused by the wording. First, is sulfide just sulfur attached to a molecule? Second, is the metal the question asks about represented by M in the given mole...

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