CHEMISTRY COMMUNITY

Megan Jung 3A

since it is square planar, the bond angles are 90 degrees

Megan Jung 3A

strong bases completely ionize in water so they consist mainly of group 1 and 2 metal ions and a hydroxide ion (OH-)

Megan Jung 3A

stronger bases will have a higher ph whereas strong acids will have a lower ph.

Megan Jung 3A

yes, this is because at some point there will be an induced dipole moment between the molecules creating some intermolecular force even if it is not very strong. This is due to electron clouds moving.

Megan Jung 3A

yes,water can act as both an acid or a base depending on what is interacting with in a reaction.

Megan Jung 3A

single bonds = sigma bond
double bonds = sigma bond and pi bond
triple bonds= sigma bond and 2 pi bonds

Megan Jung 3A

intermolecular forces are between different molecules. These forces include dipole-dipole, H bonds, and LDF or induced dipole forces. Intramolecular forces are between atoms of a molecule and include ionic and covalent bonds.

Megan Jung 3A

acids are proton donors and bases are proton acceptors.

Megan Jung 3A

No, sigma and pi bonds do not affect the molecular shape of a molecule. However, they determine whether the bond can rotate or not.

Megan Jung 3A

bond lengths are determined experimentally. However, we can compare the bond lengths of different compounds through periodic trends and atomic radii.

Megan Jung 3A

you can look at the VSEPR formula. For bent molecules, the formula can be: AX2E or AX2E2. for linear molecules the formula can be: AX2 or AX2E3 or AX2E4

Megan Jung 3A

a triple bond is composed of a sigma bond and two pi bonds. The order does not matter.

Megan Jung 3A

A polar molecule is based on the dipole moments of the molecule in relation to its 3d molecular structure. If there is a net dipole moment, then the molecule is polar resulting in partially charged sides of the molecule due to electron cloud distortion based on the electronegativity of atoms.

Megan Jung 3A

Yes, due to the lone pair repulsion the angles would be slightly less than 90 and 120.

Megan Jung 3A

The VSEPR formula for a square planar molecule is AX4E2 and tetrahedral is AX4.

Megan Jung 3A

All three have 6 regions of electrons either bonded or lone pairs. Octahedral has 6 bonding regions and 0 lone pairs. Square pyramid has 5 bonds and 1 lone pair. Square planar has 4 bonds and 2 lone pairs.

Megan Jung 3A

You would need to look at the formal charge of each atom. To get the structure at its lowest energy, try to make the formal charge on each atom as close to 0 as possible.

Megan Jung 3A

Ionization energy is the energy required to remove an electron from an atom's outermost valence shell. Electronegativity refers to the atom's ability to attract electrons.

Megan Jung 3A

Yes, as a general rule the element with the lowest ionization energy should be placed as the central atom when drawing Lewis structures.

Megan Jung 3A

Lewis structures generally depict the structure of the molecule in relation to the lone pair electrons and types of bond. The model does not cover the actual structure of the molecule. Technically, the Lewis structure shapes don't have to be representative of the actual shape of the molecule.

Megan Jung 3A

Typically, a larger anion will have a greater polarizability. This is because the electrons are not as tightly held near the nucleus and are more easily distorted. You can determine what is a larger anion by the number of protons in the element. If there is more protons, it will be smaller because t...

Megan Jung 3A

Dissociation energies are measured values that have been experimentally calculated. Therefore, they will usually be given if you need to use the values and there isn't any formulas that we need to know for this class in terms of calculating the actual value.

Megan Jung 3A

LDF/induced-dipole-dipole < dipole-dipole < hydrogen bonding< ion dipole

Megan Jung 3A

Since there are more protons across a period, there is a larger positive charge in the nucleus that will pull the electrons in closer to the nucleus. This results in a smaller radii as electrons are more tightly held which is why the atomic radii decreases across a period.

Megan Jung 3A

If a bond is longer, it is weaker than a bond that is shorter. This is why triple bonds are stronger than double bonds that are stronger than single bonds. Triple bonds have the shortest bond length and single bonds have the longest.

Megan Jung 3A

yes, this exception to the normal electron configuration will continue for the elements down the group because they will have the same valence electron configuration just different orbital levels.

Megan Jung 3A

Dissociation energy refers to the energy needed to break apart bonds of a molecule into separate atoms.

Megan Jung 3A

Yes, you would need to convert into mass per atom by using the molar mass of potassium. Once you have molar mass (g/mol) divide by avagadro's number (1mol/6.022x10^23 atoms) and finally convert g to kg for SI unites (1kg/1000g).

Megan Jung 3A

There is an exception to the ionization trend with Nitrogen and Oxygen. Based on periodic trends, one would think O has a higher ionization energy than N, however, due to the electron configuration of N this is not the case. N's electron configuration presents a half filled 2p orbital which is actua...

Megan Jung 3A

If you look at the electron configuration for nitrogen N, the p orbital is half filled with electrons. This is actually a more stable orbital compared to the oxygen O orbital. Therefore, N has a higher ionization energy because it will take more energy to remove an electron from a more stable orbital.

Megan Jung 3A

In terms of looking at trends on the periodic table of atomic radii, the atomic radius can be defined as half the distance between to bonded atoms. This is because since electrons don't have a specific location, you cannot calculate exactly the distance between the center of the atom and the end of ...

Megan Jung 3A

The 4s level has a lower energy level than 3d which is why the 4s subshell gets filled with electrons first and the 3d after. However, when writing the electron configuration you should put 3d before 4s.

Megan Jung 3A

The noble gas configuration is a short hand version of the actual electron configuration. It is usually used for elements with large atomic numbers on the periodic table to simplify. Either way is correct and can be used to represent the electron configuration of an element.

Megan Jung 3A

Cations are when an atom looses electrons in order to gain stability. Loosing an electron would give them a positive charge. Anions are formed when an atom gains an electron to achieve stability. Gaining an electron gives the atom a negative charge. Both of these are important in forming bonds betwe...

Megan Jung 3A

Elements with low ionization energy means that they require very little energy to remove an electron from their outermost valence shell. Thus, they tend to form cations and loose electrons because this would bring them to a stable octet or outer shell which is favored. Most of these elements are met...

Megan Jung 3A

m refers to the mass of the object you are calculating. In some problems, the mass is not always an atom; it could be a baseball or car. However those values usually give wavelengths that are undetectable. m can also refer to the mass of an electron or neutron.

Megan Jung 3A

For this problem, delta x, or uncertainty in position, would be 3.50 pm however you would have to convert it to meters to use the Heisenberg Indeterminacy equation. (10^12pm=1m).

Megan Jung 3A

Since you are given the velocity (v)=3.6 x 10^3 km/s, and it is known that the mass of an electron is 9.1 x 10^-31kg I would us the equation
Wavelength = h/mv.

Megan Jung 3A

For this problem, you would have to convert oz to kg and mph to km/h

The conversion for oz to kg :
5.15oz(28.3g/10oz)(1kg/1000g)

The conversion for mph to km/h:
92mi/hr(1hr/3600sec)(1.609344km/mi)

From there, use De Broglie's Equation to solve for the wavelength

Megan Jung 3A

The Indeterminacy Equation can be used to calculate the indeterminacy in momentum and the indeterminacy in position. It describes the relationship and values of the uncertainty of both of these values as given by the equation:
(delta p)(delta x)>=h/4pi

Megan Jung 3A

Threshold energy is also known as the work function. It represents the amount of energy of light is needed to remove an electron from a metal's surface. This is a specific characteristic of a metal and therefore stays constant for the same material.

Megan Jung 3A

since nm= 10^-9m
10^-10m =1 Angstrom

400nm(10^-9m/1nm)(1 A/10^-10m)
=4000 A

Megan Jung 3A

The speed of light, or 3.00 x 10^8 m/s, is a constant under a vacuum. Therefore, for the sake of calculations in problems, it is assumed that they take place under the condition of a vacuum so that we can use the equation c=v lambda in calculations.

Megan Jung 3A

Planck's constant is 6.626 x10^-34 J s. It is used to relate the energy of a particle to its frequency. The equation E=hv, we can be manipulated to h=E/v. Therefore, h or Planck's constant gives the ratio of energy to frequency and its relationship between these two variables.

Megan Jung 3A

From the photoelectric effect: For waves, the intensity is proportional to the amplitude (size) of the wave so it would have a greater energy. However, this is not the case for the photon or the particle model used for light. In this case, the light model needs a greater frequency to increase its en...

Megan Jung 3A

It depends on what the question is asking for, but typically you can use both molar mass and Avogadro's number. For example, if asked to find the number of atoms of a reactant and you are given moles you would only use Avogadro's number (6.022 x 10^23 atoms/mole) to convert. However, if you were ask...

Megan Jung 3A

Actual yield is different than theoretical yield due to error in lab. Sometimes, side reactions will occur or if there are impurities in the reactants. You should be familiar with at least one reason in case needed to explain on the test.

Megan Jung 3A

The procedure for finding the number of atoms and the number of formula units is the same. Both require use of avogadro's constant in order to convert the values. An atom refers to the single element in a equation while a formula unit refers to finding a unit of an ionic compound.

Megan Jung 3A

t means tons, so to convert it into a unit that can be used with the molar mass you would use the following conversions:
1 ton= 1,000 kg
1 kg= 1,000 mg

since the problem stated that there was 2.15 t, you would use the following unit conversions:
2.15t ( 1000 kg/t) (1000 mg/kg)
= 2.15 x 10^6 g

Megan Jung 3A

Either way is correct in determining the limiting reactant. If you convert all of the products to moles, then you should compare the molar ratios using stoichiometric coefficients to determine which reactant is the limiting reactant. However, if you choose to convert the products to grams, you are a...

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