CHEMISTRY COMMUNITY

Ethan Lam 4A

Cisplatin is an example of a chemotherapy drug that stops cancer.

Ethan Lam 4A

A solution has a lower pH if it has more hydronium ions. It has a higher pH if it has more hyroxide ions.

Ethan Lam 4A

Cisplatin has the Cl atoms on the same side while transplatin has them on opposite sides. By having Cl on the same side, cisplatin is able to block DNA.

Ethan Lam 4A

Amphiprotic describes a molecule that can both accept and donate a H+ ions. Amphoteric describes molecules that can act as an acid or a base in general. All amphiprotic substances are also amphoteric but not all amphoteric substances are amphiprotic.

Ethan Lam 4A

Electronegativity and bond strengths both play a factor in determining acid strength. Since it is more electronegative, it becomes more polar which makes it easier to dissociate.

Ethan Lam 4A

We are allowed to write the abbreviations for the specified ligands from the naming sheet

Ethan Lam 4A

Salts of weak acids produce basic solutions because the resulting anion attracts the H from water to produce OH-. The salts of weak bases produce acidic solutions because the resulting cation gives off an H to the water to make H30+. This occurs because the weak base/acid does not completely dissoci...

Ethan Lam 4A

If the lone pairs are on opposite sides then they cancel out. An example of this would be XeF4 since it is square planar and all the dipole movements from the Fs and electron pairs are negated.

Ethan Lam 4A

Hybridization is when 2 orbitals blend together. This is why carbon is capable of having 4 electron bonding spots despite only having 2 electrons in the p orbital. When the s and p orbital combine it forms 4 electron pair spots.

Ethan Lam 4A

Lewis acids are electron pair acceptors while Lewis bases are electron pair donors.

Ethan Lam 4A

Yes, water can act like both an acid and a base. Amphoteric compounds have this characteristic. Water and Al2O3 are examples of amphoteric compounds.

Ethan Lam 4A

Structural isomers have the same molecular formula, but different atom arrangements within the molecule. Stereoisomers have the same molecular formula and same atom arrangement.

Ethan Lam 4A

Yes, this is because the anion of the acid combines with the cation of the base to form a salt. The H combines with the OH to get water.

Ethan Lam 4A

Strong acids completely deprotonate. A good way to tell if something is a strong acid is if the resulting anion is stable.

Ethan Lam 4A

If it is negative then that substance is a super strong acid. If it is above 14 then that substance is a super strong base.

Ethan Lam 4A

Benzene is nonpolar since all the dipole moments cancel out.

Ethan Lam 4A

Electrons are able to go from one molecule another via the transition metal. Since the transition metal can have different charges, it is able to have different amounts of electrons and still be stable.

Ethan Lam 4A

You can find the oxidation number of a transition metal by comparing the charges of the anionic ligands to that of the overall charge of the ion.

Ethan Lam 4A

From least to greatest bond length, it would be triple bond, double bond, double bond with resonance, and then single bond. The double bond with resonance is larger than just the double bond because its bond length is between that of a double bond and a single bond.

Ethan Lam 4A

The 2px and 2py orbitals cannot form sigma bonds because the 2pz took up the only spot for the sigma bond. This is because the sigma bond is between the atoms while the pi bond is on the side. Thus, the 2px and 2py orbitals form bonds along the sides of the atom.

Ethan Lam 4A

I think we only need to know the English name.

Ethan Lam 4A

Cisplatin stops cancerous cells by stopping DNA reproduction. By having each side of the cisplatin bond with each side of DNA, it prevents the DNA from getting split and therefore copied.

Ethan Lam 4A

The definition of a ligand is a molecule that is bonded with a metal to form a coordination compound.

Ethan Lam 4A

A ligand is polydentate if it has more than one bonding atom. H20 is a monodentate despite having two electron pairs because the molecule is not long enough to reach the other bonding site of the metal. Oxalate is bidentate because it can only reach around the metal in two bonding sites.

Ethan Lam 4A

Interaction potential energy= kq1q2/r

This equation is important for finding the energy between two molecules.

Ethan Lam 4A

A molecule is polar if it has dipole movement. It is nonpolar if no dipole movement.

Ethan Lam 4A

A permanent dipole for a molecule occurs when one part of the molecule is more negative than the other part. For example, in water the hydrogen is more positive than the negative oxygen. A temporary dipole can be induced when it is in the presence of another dipole molecule. When the permanent dipol...

Ethan Lam 4A

Molecules with lone pairs have smaller bond angles because of the electron repulsion from the lone pairs that pushes other atoms away.

Ethan Lam 4A

Hydrogen bonding occurs with other atoms that have a high electronegativity. Nitrogen, oxygen, and fluorine are the usually the only ones that hydrogen reacts with since they are so electronegative.

Ethan Lam 4A

The two parts that make up a dimer can be either bonded by a covalent or intermolecular bond. Most proteins are dimers and they can be strong or weak depending on the bond to fit their intended purpose.

Ethan Lam 4A

Elements that have access to the d-orbital can have more than 8 electrons.

Ethan Lam 4A

Intermolecular forces affect the states of matter since it changes the level of attraction between molecules that keeps the material as a solid, liquid, or gas.

Ethan Lam 4A

Polarizability affects the London dispersion force since the molecules get more attracted with each other. As polarizability increases so does the strength of the dispersion force.

Ethan Lam 4A

Electron cloud distortion is the polarization of an electronegative atom. It is when the electrons from the electronegative atom move towards the atom with a small atomic radius and high effective nuclear charge since the electrons are attracted to it. This distorts the shape of the electron cloud.

Ethan Lam 4A

Chlorine has a higher electron affinity because it does not have a full orbital like neon does. You can compare electron negativity since it increases from left to right and up the group. The noble gasses have a low electron affinity since they have 8 valence electrons already.

Ethan Lam 4A

Ions that have a high polarizing power have a small atomic radius and have a high effective nuclear charge.

Ethan Lam 4A

Copper and Chromium are exceptions because it is chemically more stable for them to have a symmetric orbitals instead of a full s-orbital. For copper, it takes one away from the s-orbital to completely fill its d-orbital. For chromium, it takes one away from the s-orbital to have an electron in each...

Ethan Lam 4A

It is because the electronegativity difference between Ba and Br is greater than or equal to 2 which marks if it has definite ionic properties.

Ethan Lam 4A

Symmetry and formal charge are equally important. In question 2B.15, they say that N is the central atom.

Ethan Lam 4A

Elements that have more than 8 electrons can access the d-orbital.

Ethan Lam 4A

Bromine has 10 electrons because it has access to the d-orbital.

Ethan Lam 4A

In real life, molecules look like a blend of all the different resonance structures that can be drawn since they have the same bond length. You can tell that a molecule has resonance if it you can change the number of bonds between different atoms within a molecule without changing the location of t...

Ethan Lam 4A

It includes some of the trends. For example, atomic radius and electron shielding affect the ionization energy of an atom since inner electrons block outer electrons that are far away from the nucleus.

Ethan Lam 4A

Individual atoms within resonance structures will have different formal charges than other versions. This is because it can have a double bond in one structure and a single bond in another structure which would change the formal charge value of each.

Ethan Lam 4A

First you need to convert the eV into Joules. Then you use that value in Joules in the formula Ek=hc/(wavelenth).

Ethan Lam 4A

It is because f is the outermost orbital.

Ethan Lam 4A

The s-orbital is also symmetric because it has sphere properties.

Ethan Lam 4A

Exceptions to the periodic trends are due to that specific atom's electron configuration and Hund's rule. For example, the first ionization energy of Boron is less than that of Beryllium.

Ethan Lam 4A

We compare everything to neutral atoms because it gives us a baseline to compare ions and compounds. For example, it helps us understand the differences in ionization energy because it is easier to remove an electron away from a neutral atom instead of a cation.

Ethan Lam 4A

An electron will be removed from the orbital that has the highest amount of energy since it is easier to take out.

a.) Ge: 4p since it has two electrons in the p-orbital.
b.) Mn: 4s since 4s has a higher energy state than 3d when it is filled.
c.) Ba: 6s since it has two electrons in the s-orbital.

Ethan Lam 4A

He said that we would focus on the first row of the d-block (from Scandium to Zinc).

Ethan Lam 4A

This is because that specific element is more stable if the s-orbital donates an electron to the d-orbital since it makes it more symmetric. Silver is an example of one of these elements. However, the only two exceptions you need to know are Copper and Chromium.

Ethan Lam 4A

The electrons fill up in the different Px, Py, and Pz first as all up spin or down spin. If Px, Py, and Pz each have one electron spinning up, then the next three electrons will form pairs with them in the opposite direction.

Ethan Lam 4A

An atom is in an excited state if the electrons are in a higher energy level than normal.

Ethan Lam 4A

If the 3d orbital is filled after the 4s orbital, then why does it have less energy? Wouldn't electrons tend to fill subshells with lower energy first? Can someone please explain why this is the case? Thank you! Before the electrons fill up the orbitals, the 4s orbital has less energy than the 3d o...

Ethan Lam 4A

For me, I visualize the orbitals as spheres connected to or around the nucleus. It helps if you consider the orbitals as regions on the x, y, and z axis where electrons are present instead of a specific ring. The s-orbital has 1 lobes, the p-orbital has 3, the d-orbital has 5, and the f-orbital has ...

Ethan Lam 4A

Hi! This is not an answer, but I would like to add on to the question to ask for someone to explain the planes and the lobes, and how they are incorporated into the orbital notation which I am confused about. Thank you! The planes and the lobes are based off the orbitals. The nodal planes are the p...

Ethan Lam 4A

I think the x, y, and z subscripts only apply to the p-orbitals for Chemistry 14A purposes. You would use it in the p-orbital to indicate the 3 different places that pairs of electrons can go and the spin of the specific electron.

Ethan Lam 4A

The circular standing wave also shows the general path that the electron follows and how the line must be connected.

Ethan Lam 4A

Since light has particle and wavelike properties, light intensity depends on which property. In regards to particle properties, light intensity increases when when the number of photons increase. For wavelike properties, the intensity increases with the amplitude of the wave.

Ethan Lam 4A

They might give you partial credit though even if you leave it in fractions as long as you show your work.

Ethan Lam 4A

For part a, I got B203 + 3Mg -> 3Mg0 +2B due to Law of Conservation of Mass. For part b, you need to convert the 125 grams of both reactants into the amount of Boron by using the molar mass and the mole ratio from the balanced equation to see which reactant produces less product.

Ethan Lam 4A

Atoms can only be destroyed in nuclear reactions.

Ethan Lam 4A

Does the charge conservation work for ions too?

Ethan Lam 4A

There can only be health benefits if there are molecules still in the solution. However, since you end up with less than a molecule at the end, it would no longer be beneficial. More molecules would be helpful since it can react in the body more.

Ethan Lam 4A

It is easier to balance out the elements that appear the least in the reaction in the beginning and then work your way to oxygen. Also, if it helps write out how many atoms there are on each side of the reaction.

I got 3 Fe2O3+CO ->2 Fe3O4 +CO2 and Fe3O4 + 4 CO -> 3 Fe + 4 CO2.

Ethan Lam 4A

Percent yield is the actual yield over the theoretical yield times 100. Theoretical yield is the max amount of a product that can be produced in a given reaction (granted that nothing goes wrong and that everything is precise and accurate).

Ethan Lam 4A

I think it is better to use the SI units since they are more applicable to chemistry, especially when you are doing a lab or stoichiometry.

Ethan Lam 4A

It is because kilograms are more useful in real world applications than grams. Kilograms are better for measuring common objects since 4.5 kg of flour is simpler to say than 4500 g of flour.

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