CHEMISTRY COMMUNITY

Tiffany Vo 3G

It means it’s a really strong acid.

Tiffany Vo 3G

The charge is 2- because you calculate the formal charge on each atom. For the single bonded oxygens, the formal charge is -1 because you take the valence electrons and subtract the lone pairs and half the bonding pairs, 6-(6 + .5(2)). The double bonded oxygens have a formal charge of 0, 6-(4 + .5(4...

Tiffany Vo 3G

I don't know if this is easier, but I made the molarity of the original solution equal to 100M and the second solution's molarity equal to 12% of the original, or 12 M. It'd allow you to have actual numbers for the H3O+ concentration at least. You could then find out the pH of each solution and subt...

Tiffany Vo 3G

Strong acids also tend to form anions that are stable after it is deprotonated.

Tiffany Vo 3G

They used cyano before they changed the naming system. Cyanido is the newer naming for cyanide as a ligand, but I think Dr. Lavelle accepts either of them.

Tiffany Vo 3G

I got the same answer as you, so I think it might be a mistake in the book.

Tiffany Vo 3G

-log [H3O+] = pH. They give you that the pH is .75, so -log [H3O+] = .75. You then isolate the [H3O+]. The same thing applies for the [OH-]. You know the pH of the solution is 0.75, so you'd subtract that value from 14, giving you pOH. -log [OH-] = pOH, so -log [OH-] = 13.25. Isolate the [OH-] and t...

Tiffany Vo 3G

a) basic
b) acidic
c) amphoteric
d) amphoteric

Tiffany Vo 3G

Can anyone walk me through an example? If you're looking at 9c.1c, they give you [Co(CN)5 (OH2)] 2-. So if you'd start off by listing the ligands first: cyanide and water. If water is a ligand, you'd call it aqua and if cyanide is the ligand, you'd change it to cyanido because the ending of cyanide...

Tiffany Vo 3G

As an overview, your ligands usually come first followed by the metal atom and the oxidation state of the metal atom in Roman numerals. The ligands are supposed to be listed in alphabetical order, and greek prefixes are used to distinguish how many of each ligand is present. With the ligands, if the...

Tiffany Vo 3G

Iron is ferrate because the chemical symbol of the metal is derived from its Latin name, ferrum. I think all elements with a chemical symbol derived from a Latin stem use the beginning portion of the latin stem when naming the compound.

Tiffany Vo 3G

There's a table on page 724 that's super helpful for memorizing the more common ligands, so I'm assuming we'll probably have to know at least those ones for the test.

Tiffany Vo 3G

Induced dipole-induced dipole forces can occur in all molecules because all molecules have electron clouds that can be distorted by shifting electron clouds in another molecule.

Tiffany Vo 3G

With gases, they occupy more space so the attraction between the molecules are weak. Solids on the other hand are more restricted in their movement, so they have stronger dipole-dipole interactions than gases would.

Tiffany Vo 3G

Greek prefixes indicate the number of ligands, so you use the other prefixes to prevent confusion. I think you use those prefixes when the ligand has a greek prefix already in the name or if the ligand is polydentate.

Tiffany Vo 3G

A ligand is an ion or molecule that's attached to a central metal atom and creates a coordination complex.

Tiffany Vo 3G

I think in lecture today Dr. Lavelle said that we would also have to know pi and sigma bonds, but I think we're going over that on Monday.

Tiffany Vo 3G

Dipole-dipole interactions exist between polar molecules because one end of the molecule is more negatively charged while the other end is more positively charged. With a, the molecule is nonpolar because the electronegativity difference between the C-H bond isn't large enough to constitute a perman...

Tiffany Vo 3G

If given the grams of reactants, you can technically convert each reactant to moles and then convert one of the reactants to moles of the other reactant and use the coefficients in the chemical equation to determine the limiting reactant. So for instance, if you have 2H2 + O2 --> 2H2O and you find t...

Tiffany Vo 3G

Arianna Perea 3H wrote:If it has more surface area, will the boiling point be higher?

The boiling point should be higher if the molecule has more surface area.

Tiffany Vo 3G

In terms of repulsion strength, lone pair-lone pair experiences higher repulsion than lone pair-bonding pair, and lone pair-bonding pair experiences a higher repulsion than bonding pair-bonding pair. That means in order for the molecule to be bent, there must be lone pairs that push the bonding elec...

Tiffany Vo 3G

I don't think it really matters so long as you get the right answer, but I think Dr. Lavelle prefers that we use the one he taught in class because it allows us to conceptually understand what's occurring. Using his equation might also guarantee partial credit if you get part of the problem wrong, b...

Tiffany Vo 3G

I don't think it really matters so long as you get the right answer, but I think Dr. Lavelle prefers that we use the one he taught in class because it allows us to conceptually understand what's occurring. Using his equation might also guarantee partial credit if you get part of the problem wrong, b...

Tiffany Vo 3G

Covalent bonds are stronger than ionic bonds in an organic system because in an aqueous environment, the positive end of water molecules would surround the anion of an ionic compound and the negative end of water molecules would surround the cation of the ionic compound. In a vacuum however, the cov...

Tiffany Vo 3G

The intermolecular forces occur due to attraction of one atom to another atom, but they don't share electrons. Typically, intermolecular forces are indicated using dashed lines as opposed to a solid line because it is a weaker force than a chemical bond.

Tiffany Vo 3G

It should be between the individual ions, so in this case, between the Na+ and Cl- ions. Technically, I think they would be the strongest type of bond in a vacuum, but it is weaker than covalent bonds in water.

Tiffany Vo 3G

I think the stronger the intermolecular force between the atoms, the higher the normal melting point because it'll take more energy to break the bonds. So like for the first one, I think NaCl has a higher melting point, but I'm not totally sure.

Tiffany Vo 3G

a) Co^2+

b) Fe^2+

c) Cr^2+

d) V^2+

Tiffany Vo 3G

There's also ionic radius, which increases down a group and decreases across period.

Tiffany Vo 3G

The fourth number is the spin, so you can either choose +1/2 or -1/2. It's arbitrary so long as you remember that no two electrons can have the same four quantum numbers, so if n, l, and ml are the same, you have to make sure one of the electrons has a ms value of 1/2 and the other has -1/2.

Tiffany Vo 3G

I think that the noble gases are still subject to the trends for atomic radius and ionization energy, but I don't think that the other trends apply because noble gases are unlikely to lose or gain electrons.

Tiffany Vo 3G

I'm still confused as to what the relationship between the deBroglie wavelength and the mass is? If an atom has a longer wavelength does that mean it has a lighter mass or? The debroglie wavelength and the mass is inversely proportional because the formula is wavelength equals h/mv. If the atom has...

Tiffany Vo 3G

Sulfur is capable of forming 6 bonds as seen in SF6 but I'm not sure if we need to know that particular exception.

Tiffany Vo 3G

I think the second ionization energy is higher than the first ionization energy because there's more effective nuclear charge. (I might be wrong though).

Tiffany Vo 3G

I think the configuration for Ag+ is 4d^10 because if the 5s state is already filled, the 4d state is more stable. I think it's because a half full d orbital or a full d orbital has less energy than an s orbital.

Tiffany Vo 3G

Anions are usually larger than cations because anions usually experience more shielding.

Tiffany Vo 3G

If the element is past the second period in the periodic table does it still need to follow the octet rule? Almost all atoms follow the octet rule because it's more stable, except for hydrogen, helium, lithium and beryllium. With those atoms, having a different number of bonds aids in the stability...

Tiffany Vo 3G

Photons also don't have a discernable mass while other particles do, so sometimes using photon over particle would be more specific.

Tiffany Vo 3G

You'd have to pull the electrons from the highest energy orbital. I think the outermost electrons are easier to remove because the outermost electrons experience less electrostatic attraction.

Tiffany Vo 3G

You're missing one more conversion factor. There's 60 minutes in an hour, so you just forgot to multiply by 1 min/60 seconds. If you correct that mistake, you should get 34.72 m/s and then you plug that value into the equation. It shouldn't have wavelike properties because the answer gets you 6.94 x...

Tiffany Vo 3G

I think it's because the probability of finding an electron can't be negative? The trough of the wave would be considered negative if psi represents the height of the wave, so squaring it should make the probability positive (I think).

Tiffany Vo 3G

For the first question, you'd have to use c = wave length x frequency, so you'd divide 3 x 10^8 meters per second by 7.1 x 10^14 Hz. If it helps, 1 Hz is equivalent to 1/second, so your units should cancel out and leave you just your wavelength. After that, it's just a matter of converting the meter...

Tiffany Vo 3G

The correct answer is that you can't be certain of the momentum and position of the particle simultaneously. It's basically the idea that by the time you determine the exact position of the particle at an exact time, you no longer have an idea of the momentum of the particle. Likewise, by the time y...

Tiffany Vo 3G

I think intensity is basically a measure of how many photons are available. With intensity, it usually correlates to the wave model of light, but frequency typically correlates with the photon model of light. Frequency is increased when wavelengths are shorter, but that has no correlation to the amp...

Tiffany Vo 3G

When I am solving a problem, do I have to keep in mind the sigfigs throughout all the calculations? Or just keep the right sigfigs for the final answer. I think you just need to keep the same sig figs for the final answer because it's better for accuracy to round at the end. I'm pretty sure roundin...

Tiffany Vo 3G

The law of conservation of mass should apply to all problems, so you should be able to subtract the mass of cobalt from the final compound's mass to find the mass of fluorine gas originally involved in the reaction. After finding the mass of the fluorine, you should be able to convert each of those ...

Tiffany Vo 3G

Combustion is an oxidation reaction, meaning it would involve oxygen because it receives an electron from the oxygen molecule. With most combustion reactions, they tend to form water and carbon dioxide.

Tiffany Vo 3G

I think you're technically supposed to know it because it is basically a nitrate ion (NO3-) with an added hydrogen atom. It tends to come up fairly often in chemistry, so it's really helpful to have it memorized. Assuming that the polyatomic ion that is being protonated ends with -ate (like nitrate)...

Tiffany Vo 3G

I would assume that he'll grade us based on our significant figures because it determines the accuracy of measurements. The accuracy is really important for determining error because no scientific tool can ever determine a measurement perfectly; there's always some discrepancy.

Tiffany Vo 3G

Titrations are essentially used to determine the molarity of a solution. If you had an unknown solution of some acid, you could use a basic solution with known concentration to determine the molarity of the acidic solution. You would add an indicator to the acidic solution and then continuously add ...

Tiffany Vo 3G

Basically, the percentage yield is the amount of product in grams you have obtained through experimentation divided by the amount of product in grams you would get if no product was lost during the experiment. So first you'd have to convert the 35.0 grams of NH3 to moles using its molar mass and the...

Tiffany Vo 3G

I think SnO2 is actually considered Tin (IV) oxide. You would have to look at the oxidation states of the individual atoms to determine if it was Tin (IV) or Tin (II). Oxygen tends to have an oxidation state of -2, and the oxidation state of neutral compounds is zero, so to be SnO2, the oxidation st...

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