## Search found 50 matches

Thu Dec 10, 2020 5:30 pm
Forum: Air Pollution & Acid Rain
Topic: Respiratory Acidosis
Replies: 4
Views: 214

### Re: Respiratory Acidosis

Decreased respiration can result in respiratory acidosis, as it raises the concentration of CO2 and H2CO3 in the blood, decreasing its pH.
Thu Dec 10, 2020 5:12 pm
Forum: Identifying Acidic & Basic Salts
Topic: Salt Acidic Ions
Replies: 3
Views: 23

### Re: Salt Acidic Ions

NH4Cl would dissociate into NH4+ and Cl- ions. NH4+ ions can then lose their H+ to form NH3, making the overall solution more acidic.
Thu Dec 10, 2020 4:53 pm
Forum: Polyprotic Acids & Bases
Topic: Calculating Ka
Replies: 9
Views: 80

### Re: Calculating Ka

Since Ka requires the concentrations of relevant reactants and products, you would need to use molarity.
Thu Dec 10, 2020 4:31 pm
Forum: Lewis Acids & Bases
Topic: Acids question
Replies: 4
Views: 31

### Re: Acids question

The Ka value can be used to compare the strengths of different acids, though I don't think we'll be required to actually calculate it in this class.
Thu Dec 10, 2020 4:26 pm
Forum: Lewis Acids & Bases
Topic: KA and pKA
Replies: 19
Views: 144

### Re: KA and pKA

Ka is the acid dissociation constant, while pKa is the negative log of the Ka value. Both can be used to infer the strength of an acid, though they do have an inverse relationship.
Thu Dec 03, 2020 5:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Textbook Problem 2E.1
Replies: 2
Views: 17

### Re: Textbook Problem 2E.1

A good example would be a molecule such as SF4, which has a seesaw molecular geometry. S forms four bonds, but has a lone pair as well. The two axial fluorines in the compound form a 180-degree bond angle. There are many possible structures that satisfy both criteria, though you are correct in belie...
Thu Dec 03, 2020 4:44 pm
Forum: Hybridization
Topic: pcl3
Replies: 8
Views: 50

### Re: pcl3

There are a total of four regions of electron density, as lone pairs and bonds are both considered regions of electron density. PCl3 thus forms sp3 hybridization, with one of the hybridized orbitals holding the lone pair.
Thu Dec 03, 2020 4:36 pm
Forum: Hybridization
Topic: identification
Replies: 5
Views: 66

### Re: identification

BrF3 has five regions of electron density, as it forms three bonds and has two lone pairs. Based on this information, it can be concluded that Br forms sp3d hybridization.
Thu Dec 03, 2020 4:15 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Strength of Acids
Replies: 8
Views: 67

### Re: Strength of Acids

HBr is indeed stronger, as it dissociates more easily than HCl, resulting in a higher concentration of H+ in solution.
Thu Dec 03, 2020 4:11 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid strength and bond length
Replies: 11
Views: 88

### Re: Acid strength and bond length

Longer bonds are weaker, which makes for stronger acids. Acid strength is determined by percent dissociation, with stronger acids dissociating more. HBr is thus a stronger acid, as it more easily dissociates in water.
Thu Nov 26, 2020 9:31 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Nitric Oxide
Replies: 5
Views: 84

### Re: Nitric Oxide

NO is linear, and polar, as there exists a dipole due to the difference in electronegativity between N and O. The unpaired electron does not affect its shape, as a molecule containing two atoms must be linear.
Thu Nov 26, 2020 9:21 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: carbon hydrogen bonds
Replies: 6
Views: 36

### Re: carbon hydrogen bonds

The overall shape of the molecule would still be tetrahedral, as relative to the central atom, there are still only four regions of electron density. CCl4 is a good example of this, as it still forms a tetrahedral much like CH4.
Thu Nov 26, 2020 9:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: coplanar?
Replies: 9
Views: 53

### Re: coplanar?

It means that the atoms within the molecule lie in the same plane, which can be thought of as just a flat surface.
Thu Nov 26, 2020 9:12 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lecture #20
Replies: 4
Views: 57

### Re: Lecture #20

Lone pairs are also considered as regions of high electron density, and must be accounted for when determining the electron arrangement. They are however not taken into account when determining the molecular shape, as only the positions of the actual atoms in the molecule are considered.
Thu Nov 26, 2020 9:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pair Volume
Replies: 4
Views: 17

### Re: Lone Pair Volume

A lone pair is only restricted by the electrostatic pull of a single atom's nucleus, while bonding pairs are restricted by two. They are thus more diffuse, and take up a larger volume as a result.
Thu Nov 19, 2020 5:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Why aren't the bond angles in PCl5 maximized?
Replies: 3
Views: 41

### Re: Why aren't the bond angles in PCl5 maximized?

They are actually maximized, it's just that because PCl5 has to accommodate for an extra bond, its angles are smaller. It has an extra area of electron density, and is thus unable to spread them as far apart as CH4 can.
Thu Nov 19, 2020 5:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: lone pairs
Replies: 6
Views: 68

### Re: lone pairs

Lone pairs are only restricted by the singular nucleus they are close to, while bonding pairs are restricted by two. They are thus more free in this sense, and naturally, take up a greater volume as a result.
Thu Nov 19, 2020 5:12 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: London Dispersion Forces
Replies: 9
Views: 94

### Re: London Dispersion Forces

You should also consider the size of the compounds, as larger compounds generally experience stronger dispersion forces. This occurs because larger compounds exert weaker attractive forces on their outer electrons, making them more polarizable.
Thu Nov 19, 2020 4:49 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: H-Bonding clarification
Replies: 7
Views: 98

### Re: H-Bonding clarification

A hydrogen bond will form regardless of whether or not the original N, O, F has any lone pairs.
Thu Nov 19, 2020 4:34 pm
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: London Forces [ENDORSED]
Replies: 19
Views: 132

### Re: London Forces[ENDORSED]

Yes, as electrons are always moving about, creating induced dipoles.
Thu Nov 12, 2020 5:37 pm
Forum: Bond Lengths & Energies
Topic: Sapling HW Bond Length
Replies: 7
Views: 60

### Re: Sapling HW Bond Length

S has a larger atomic radius, as it has an extra electron shell. The Si-S bond is longer because of this difference in the atomic radii of S and O.
Thu Nov 12, 2020 5:26 pm
Forum: Dipole Moments
Topic: Hydrogen Bonds
Replies: 6
Views: 47

### Re: Hydrogen Bonds

Hydrogen bonds are intermolecular interactions, and are weaker than the bonds that form within individual compounds.
Thu Nov 12, 2020 5:15 pm
Forum: Dipole Moments
Topic: induced dipole vs dipole
Replies: 11
Views: 44

### Re: induced dipole vs dipole

Induced dipole-induced dipole interactions are temporary, and present in all substances. Dipole-dipole interactions are only present in polar compounds, and are stronger in comparison.
Thu Nov 12, 2020 5:10 pm
Forum: Dipole Moments
Topic: Liquid vs. Solid vs. Gas
Replies: 5
Views: 33

### Re: Liquid vs. Solid vs. Gas

Polarizability is proportional to the strength of the dispersion forces, which is what holds the compounds together. A substance's state of matter depends on its intermolecular forces, which is why the two are related.
Thu Nov 12, 2020 5:01 pm
Forum: Dipole Moments
Topic: Determining Polarity
Replies: 3
Views: 28

### Re: Determining Polarity

The difference in electronegativity values can also be used to determine polarity, as it indicates an unequal sharing of electrons, leading to delta positives and negatives.
Thu Nov 05, 2020 5:58 pm
Forum: Lewis Structures
Topic: Lewis structures and charges
Replies: 3
Views: 34

### Re: Lewis structures and charges

The charge indicates a loss or gain of electrons, as the molecule is considered to be an ion. A negative charge indicates that there are more electrons than protons, which is why we add the charge to the total amount of valence electrons in the molecule. A positive charge indicates the opposite, and...
Thu Nov 05, 2020 5:48 pm
Forum: Lewis Structures
Topic: First 3 elements' octet
Replies: 4
Views: 34

### Re: First 3 elements' octet

Since the first energy level can only hold 2 electrons, H and He do not form octets. Although Li has one electron in the second energy level, it would need to gain seven more to form an octet. This is unlikely as Li has a relatively low ionization energy, and is thus likely to lose its single valenc...
Thu Nov 05, 2020 5:37 pm
Forum: Lewis Structures
Topic: Relationship between Periods and Orbitals
Replies: 1
Views: 23

### Re: Relationship between Periods and Orbitals

Fluorine is in the second period, which means it has a principal quantum number of n = 2. Its angular momentum quantum number can thus only be l = 0 or l = 1. l = 0 corresponds to the s-orbital, while l = 1 corresponds to the p-orbitals. Chlorine, on the other hand, is in the third period, and so l ...
Thu Nov 05, 2020 5:27 pm
Forum: Lewis Structures
Topic: Valence Electrons
Replies: 10
Views: 67

### Re: Valence Electrons

Elements within the periodic table are sorted into different groups, and looking at these group numbers should tell you the valence electrons of different elements. For p-block elements, you can subtract ten from the group numbers to find the number of valence electrons.
Thu Nov 05, 2020 5:18 pm
Forum: Lewis Structures
Topic: Formal Charges
Replies: 7
Views: 51

### Re: Formal Charges

Formal charge is a way to measure the relative charges of atoms within a molecule, assuming that all bonds are shared equally among the atoms. There aren't atoms that must hold formal charges, it all depends on the molecule you're looking at.
Thu Oct 29, 2020 8:29 pm
Forum: Trends in The Periodic Table
Topic: effective nuclear charge
Replies: 2
Views: 36

### Re: effective nuclear charge

Electrons further away from the nucleus are shielded by electrons closer to it, and so they don't experience the full nuclear charge. The effective nuclear charge is thus the charge felt by a specific electron, while the nuclear charge is the actual positive charge of the nucleus.
Thu Oct 29, 2020 8:22 pm
Forum: Trends in The Periodic Table
Topic: Sapling Hw 2, 3, 4 Question 20
Replies: 4
Views: 43

### Re: Sapling Hw 2, 3, 4 Question 20

Oxygen has 4 electrons in the p-subshell, meaning one of the p-orbitals contains two electrons. Because both electrons are negatively charged, they will naturally repel each other, making it easier to remove an electron from that orbital. Nitrogen, on the other hand, has only one electron in each p-...
Thu Oct 29, 2020 8:11 pm
Forum: Trends in The Periodic Table
Replies: 3
Views: 22

The element at the beginning of the next period would likely still have a larger radius, as it possesses an extra shell.
Thu Oct 29, 2020 8:07 pm
Forum: Trends in The Periodic Table
Topic: In class question
Replies: 8
Views: 62

### Re: In class question

The atomic radius would still exist, though I don't think you would be able to calculate it. You would need something like chlorine gas, which has 2 chlorine atoms covalently bonded to one another.
Thu Oct 29, 2020 8:02 pm
Forum: Trends in The Periodic Table
Replies: 30
Views: 411

Going across a row would result in more electron repulsions, though I believe that the increase in the number of protons in the nucleus would overcome this.
Thu Oct 22, 2020 7:03 pm
Forum: Einstein Equation
Topic: Einstein's Equation
Replies: 7
Views: 106

### Re: Einstein's Equation

It basically just says that if the energy of the photon is larger than the work function (the energy it takes to remove the electron), that excess will be converted into kinetic energy of the ejected electron. The equation helps to support the idea that light is also a particle, as only photons of l...
Thu Oct 22, 2020 6:54 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Light's effects
Replies: 8
Views: 99

### Re: Light's effects

It has to do with the difference in momentum, which depends on both velocity and mass. The baseball has a much higher mass, and thus a much larger momentum. The effect of the photon striking it will be negligible, and thus no uncertainty is really observed. It is the opposite for the electron, as it...
Thu Oct 22, 2020 6:41 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Heisenberg Diagram from Lecture
Replies: 5
Views: 56

### Re: Heisenberg Diagram from Lecture

The second detector determines both the final time and distance, which you would need if you wanted to find the velocity.
Thu Oct 22, 2020 6:39 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Applied to particles other than electrons
Replies: 5
Views: 23

### Re: Applied to particles other than electrons

It applies to objects on the macroscopic scale as well, though it is only noticeable on objects in the microscopic world, such as electrons, protons, neutrons, etc.
Thu Oct 22, 2020 6:29 pm
Forum: DeBroglie Equation
Topic: Rearranging De Broglie Equation
Replies: 17
Views: 116

### Re: Rearranging De Broglie Equation

If you multiplied both sides of the equation by velocity, then divided both sides by wavelength, you'd end up with v = h / mλ.
Thu Oct 15, 2020 7:34 pm
Forum: DeBroglie Equation
Topic: Wavelengths and DeBroglie
Replies: 7
Views: 87

### Re: Wavelengths and DeBroglie

The baseball technically is both a particle and a wave, though it doesn't exhibit any measurable wave-like properties. I'm assuming the question is asking whether or not its wave-like properties are noticeable, as all matter is technically a wave and a particle.
Thu Oct 15, 2020 7:30 pm
Forum: Photoelectric Effect
Topic: Excess energy
Replies: 20
Views: 135

### Re: Excess energy

If the photon has excess energy after removing the electron, that excess energy will be converted into kinetic energy for the electron.
Thu Oct 15, 2020 7:24 pm
Forum: Einstein Equation
Topic: Einstein Equation
Replies: 10
Views: 223

### Re: Einstein Equation

The "h" is Planck's constant, around 6.626x10^-34 Js. The "v" is the frequency of the photon.
Thu Oct 15, 2020 7:19 pm
Forum: Properties of Light
Topic: Balmer vs Lyman
Replies: 12
Views: 108

### Re: Balmer vs Lyman

The Balmer series involves electrons dropping from a higher energy level to n=2, while the Lyman series involved electrons dropping from a higher energy level to n=1. The Lyman series results in higher frequency light as the difference in energy between two consecutive energy level decreases as n go...
Thu Oct 15, 2020 7:06 pm
Forum: Properties of Electrons
Topic: protons and electrons
Replies: 33
Views: 191

### Re: protons and electrons

Protons and neutrons are similar in mass, while electrons are much smaller than both. The mass of an atom is almost entirely dependent on the nucleus, as the electrons weigh so little in comparison.
Thu Oct 08, 2020 6:22 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Moles vs molecules
Replies: 14
Views: 152

### Re: Moles vs molecules

A molecule is a compound made from atoms chemically bonded together. A mole is a number used to provide the quantity of a group of things, specifically 6.022x10^23. This can include molecules, but it really can be anything, though you likely won't encounter this measurement in the macroscopic world,...
Thu Oct 08, 2020 6:11 pm
Forum: Balancing Chemical Reactions
Topic: Periodic Table
Replies: 50
Views: 484

### Re: Periodic Table

I think it is highly unlikely we would need to memorize all the elements, though it probably would be a good idea to familiarize yourself with the more common ones, such as hydrogen(H), oxygen(O), carbon(C), etc.
Thu Oct 08, 2020 6:06 pm
Forum: Balancing Chemical Reactions
Topic: Combustion Products
Replies: 13
Views: 69

### Re: Combustion Products

You should always check to see if it's balanced, as depending on the compound being combusted, you would create different amounts of H2O and CO2.
Thu Oct 08, 2020 6:03 pm
Forum: Empirical & Molecular Formulas
Topic: difference between empirical and molecular
Replies: 15
Views: 70

### Re: difference between empirical and molecular

Assuming the question you're answering gives you the molar mass of the actual molecule, you should first find the molar mass of the empirical formula, and then divide the molar mass of the molecule by it. If the factor you get from this division is 1, they would be equal. If not, multiply each eleme...
Thu Oct 08, 2020 5:58 pm
Forum: SI Units, Unit Conversions
Topic: Sapling Assignment 1 Question 6
Replies: 16
Views: 129

### Re: Sapling Assignment 1 Question 6

You would first need to convert from grams to moles using the molar mass of CuNO3. Then you can just plug in the molarity and moles into the equation M = n / V, and solve for volume. Your answer would be in liters, and so you would have to convert it to milliliters by multiplying it by 1000.