Search found 102 matches

by ALegala_2I
Mon Mar 16, 2020 2:22 pm
Forum: Balancing Redox Reactions
Topic: Test 2 Return
Replies: 20
Views: 330

Re: Test 2 Return

Test 2 and the corresponding answer keys can be found here.

viewtopic.php?f=160&t=62122&p=237630&sid=fbd87ea7b2442d1db0b2bd7a14b04e68#p237630
by ALegala_2I
Wed Mar 11, 2020 2:46 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Bottle Neck Effect
Replies: 4
Views: 72

Re: Bottle Neck Effect

The first step is fast and the second step is slow.
by ALegala_2I
Tue Mar 10, 2020 8:47 am
Forum: Zero Order Reactions
Topic: Zero Order
Replies: 8
Views: 58

Re: Zero Order

Are zero order reactions common?
by ALegala_2I
Tue Mar 10, 2020 8:47 am
Forum: General Rate Laws
Topic: 7A.3
Replies: 6
Views: 69

Re: 7A.3

Since the question is asking about the rate of consumption, it is already taking into account that oxygen is being used up. Therefore the answer is meant to be positive in terms of consumption rate.
by ALegala_2I
Mon Mar 09, 2020 10:53 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Derivation of Arrhenius
Replies: 2
Views: 30

Derivation of Arrhenius

How do you derive this equation from the Arrhenius Equation?

Image
by ALegala_2I
Mon Mar 09, 2020 10:49 am
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate laws for reaction mechanisms
Replies: 3
Views: 46

Re: Rate laws for reaction mechanisms

I also had the same question. We did not do any practice problems in class and it seems particularly complex.
by ALegala_2I
Wed Mar 04, 2020 3:35 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Rate-Determining Step
Replies: 4
Views: 72

Re: Rate-Determining Step

You can determine the rate limiting reaction from the rate law.
by ALegala_2I
Tue Mar 03, 2020 10:25 am
Forum: General Rate Laws
Topic: rate law definition
Replies: 4
Views: 40

Re: rate law definition

The rate law tells you the instantaneous reaction rate in terms of the concentration. Each reaction has a unique rate law which is specific to its reactants.
by ALegala_2I
Tue Mar 03, 2020 10:22 am
Forum: First Order Reactions
Topic: first order graphs
Replies: 2
Views: 49

Re: first order graphs

For first order reactions, it is good to know how the graph looks in terms of [A] and ln[A]. Below is general trend for first order reactions in both situations. https://saylordotorg.github.io/text_general-chemistry-principles-patterns-and-applications-v1.0/section_18/0fd0e9359ab66f04b9ee0e414d2d9a9...
by ALegala_2I
Mon Mar 02, 2020 10:26 am
Forum: Method of Initial Rates (To Determine n and k)
Topic: k
Replies: 10
Views: 96

Re: k

Capital K is the equilibrium constant while lower case k is the rate constant for kinetics.
by ALegala_2I
Mon Mar 02, 2020 10:25 am
Forum: General Rate Laws
Topic: Half Lives
Replies: 3
Views: 66

Re: Half Lives

Yes, you need to use half life. Since 1/4 is (1/2)^2, to have your final concentration be a fourth of the initial, it would take two half lives. Correspondingly, it would take 3 half lives to to get 1/8 of the initial.
by ALegala_2I
Thu Feb 27, 2020 9:33 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E cell
Replies: 2
Views: 18

Re: E cell

You can use the equation, E = Eo - RT ln Q, to find the electric potential under non standard conditions.
by ALegala_2I
Wed Feb 26, 2020 10:06 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: 6M7
Replies: 3
Views: 46

Re: 6M7

Use the value that corresponds with reduction potential for the substance in a solid state.
by ALegala_2I
Wed Feb 26, 2020 10:05 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: determining unknown quantity in cell
Replies: 2
Views: 42

Re: determining unknown quantity in cell

For the units to cancel out correctly, you have to use R = 8.314 J/(mol*K). Whenever you need to decide what R to use, always check the units of the other values given.
by ALegala_2I
Mon Feb 24, 2020 7:43 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Concentration Cells
Replies: 5
Views: 55

Re: Concentration Cells

In the example during class, a porous membrane separated the two sides of the cell. However, only then anion was able to pass this membrane.
by ALegala_2I
Mon Feb 24, 2020 11:37 am
Forum: Balancing Redox Reactions
Topic: 6K.3 part d
Replies: 3
Views: 45

Re: 6K.3 part d

I believe that the product is supposed to be Cl- not Cl2.
by ALegala_2I
Wed Feb 19, 2020 10:24 am
Forum: Balancing Redox Reactions
Topic: What is being reduced/oxidized in this rxn?
Replies: 4
Views: 69

Re: What is being reduced/oxidized in this rxn?

I believe it is an error in the question. It should be Cl2 --> 2Cl-. This will show the change in oxidation state.
by ALegala_2I
Wed Feb 19, 2020 10:21 am
Forum: Balancing Redox Reactions
Topic: Oxidation Number Rules
Replies: 7
Views: 101

Re: Oxidation Number Rules

Here is a chart that can help with oxidation numbers.


Image
by ALegala_2I
Tue Feb 18, 2020 3:41 pm
Forum: Balancing Redox Reactions
Topic: Finding charge
Replies: 2
Views: 42

Re: Finding charge

You can also find the charge by looking at the charge of the compound as a whole. For example if you have MnO4-. The total net charge for the compound is -1 and we know that oxygen has a oxidation number of -2. Since there are 4 oxygens we know that the total charge that comes form the oxygens are -...
by ALegala_2I
Mon Feb 17, 2020 12:58 pm
Forum: Van't Hoff Equation
Topic: When to Use Vant Hoff
Replies: 5
Views: 72

Re: When to Use Vant Hoff

You either have to be given the standard enthalpy or find it using a table of values to solve for the delta H.
by ALegala_2I
Mon Feb 17, 2020 12:48 pm
Forum: Balancing Redox Reactions
Topic: Oxidizing/Reducing Agents
Replies: 11
Views: 141

Oxidizing/Reducing Agents

What are oxidizing agents and reducing agents?
by ALegala_2I
Wed Feb 12, 2020 11:16 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible vs Irreversible
Replies: 5
Views: 145

Re: Reversible vs Irreversible

From what we learned, we only distinguished our calculation for reversible and irreversible to calculate work and the total change in entropy of the universe.
by ALegala_2I
Tue Feb 11, 2020 11:54 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Questions about Equation Sheet
Replies: 3
Views: 50

Re: Questions about Equation Sheet

Actually, both of the c values are for monoatomic gases. Cv is used when the reaction is carried out at a constant volume and Cp is used at constant pressure.

[img]Screen%20Shot%202020-02-11%20at%2011.53.40%20AM[/img]
by ALegala_2I
Tue Feb 11, 2020 11:44 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: 4F.17
Replies: 1
Views: 38

Re: 4F.17

You have to use the deltaS = nCln(T2/T1) equation. First, you use this equation to raise the temperature of water from 85 - 100 (make sure you convert to Kelvin) and use the molar heat capacities at constant pressure of liquid water. Then, you use this equation to lower the temperature of water from...
by ALegala_2I
Mon Feb 10, 2020 2:21 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Microstates
Replies: 6
Views: 62

Re: Microstates

How many microstates does the molecule BF3 have for the B-F bond?
by ALegala_2I
Mon Feb 10, 2020 2:13 pm
Forum: Calculating Work of Expansion
Topic: Reversible and Isobaric
Replies: 4
Views: 67

Re: Reversible and Isobaric

The irreversible equation is only used when pressure is constant. If pressure is changing, then you use the reversible equation.
by ALegala_2I
Wed Feb 05, 2020 12:18 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: 4D.7
Replies: 1
Views: 33

Re: 4D.7

Work is being done because there is a change in the moles of gas from reactants to products. When not specified, we assume that the reaction is being done under ideal conditions.
by ALegala_2I
Tue Feb 04, 2020 8:31 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: R vs C
Replies: 2
Views: 26

Re: R vs C

R is the gas constant which is on the equation sheet. C is the specific heat capacity which is usually given in the problem.
by ALegala_2I
Tue Feb 04, 2020 8:29 am
Forum: Calculating Work of Expansion
Topic: when to use...?
Replies: 4
Views: 47

Re: when to use...?

You use w=-PV when there is an expansion occurring at a constant external pressure. You use the other equation when there is a change in internal and external pressure for expansion work.
by ALegala_2I
Mon Feb 03, 2020 10:29 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: First Law
Replies: 5
Views: 71

Re: First Law

In an isolated system, there is no transfer of heat or matter. In terms of internal energy (U=q+w), there is no heat exchange so q=0 and no change in matter so w=0. This means that the change in internal energy is equal to zero and that it remains constant throughout an experiment on an isolated sys...
by ALegala_2I
Mon Feb 03, 2020 10:24 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4C.9A
Replies: 2
Views: 27

Re: 4C.9A

The question is essentially asking how much energy it takes to heat the copper kettle which has its own unique specific heat capacity and how much energy it takes to heat the water. You have to perform two calculations to get the total change in energy.
by ALegala_2I
Wed Jan 29, 2020 9:33 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: 4A. 13 Homework
Replies: 2
Views: 18

Re: 4A. 13 Homework

Since we are measuring the q of the reaction and we know that heat is being released, the reaction is exothermic, making the q negative.
by ALegala_2I
Tue Jan 28, 2020 10:02 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb calorimetry
Replies: 3
Views: 26

Re: Bomb calorimetry

Bomb calorimeters are more sophisticated versions of regular calorimeters. The reaction takes place in a metal vessel with a constant volume. This metal vessel is in water and the temperature change is monitored.
by ALegala_2I
Tue Jan 28, 2020 9:56 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific heat as an intensive property
Replies: 2
Views: 15

Re: Specific heat as an intensive property

Heat capacity is an extensive property because it varies by the amount of the substance in the situation. Specific heat capacity measures the amount of heat to raise one mole or one gram of a substance by one degree celsius. Since it is per mole or per gram, it can be applied to a variety of situati...
by ALegala_2I
Mon Jan 27, 2020 9:58 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpy of Diatomic Gases
Replies: 4
Views: 38

Standard Enthalpy of Diatomic Gases

Why is the standard enthalpy of diatomic gases (O2) equal to zero?
by ALegala_2I
Mon Jan 27, 2020 9:48 am
Forum: Phase Changes & Related Calculations
Topic: Steam vs water
Replies: 5
Views: 56

Re: Steam vs water

How does the delta H of water when it is melting compare to the delta H of water when it is vaporizing?
by ALegala_2I
Wed Jan 22, 2020 9:23 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's in relation to stability
Replies: 3
Views: 46

Re: Le Chatelier's in relation to stability

You can however determine the relative stability of the reactants and products by looking at the Ka value. If it is very large, the products are more stable and if it is very small, the reactants are more stable.
by ALegala_2I
Tue Jan 21, 2020 11:28 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Checking the approximation of "x"
Replies: 4
Views: 29

Re: Checking the approximation of "x"

The approximation is also acceptable if the Ka value is less than 10^-3.
by ALegala_2I
Tue Jan 21, 2020 11:28 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: exothermic reactions
Replies: 19
Views: 196

Re: exothermic reactions

Does this mean that cooling an exothermic reaction will favor the products?
by ALegala_2I
Mon Jan 20, 2020 9:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Pressure goes to less moles of gas explaination
Replies: 4
Views: 30

Re: Pressure goes to less moles of gas explaination

When you increase pressure, you are decreasing the volume. This relationship is seen in the PV=nRT equation. A decrease in volume means an increase in concentration. To balance out the increase in concentration, the equilibrium will go toward the side with fewer moles.
by ALegala_2I
Wed Jan 15, 2020 9:31 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Real reason explaining Le Chatelier's principle
Replies: 4
Views: 44

Re: Real reason explaining Le Chatelier's principle

When pressure increases, there is a decrease in volume. This inverse relationship can be seen through the PV=nRT equation. When the volume decreases, this means that the concentration (n/V) of all products and reactants increases. Due to the increase in concentration, the reaction will proceed towar...
by ALegala_2I
Tue Jan 14, 2020 9:48 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature change
Replies: 5
Views: 33

Re: Temperature change

Why do changes in concentration, pressure, and volume have no effect on the K value?
by ALegala_2I
Tue Jan 14, 2020 9:46 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: pKa
Replies: 3
Views: 30

Re: pKa

A lower pKa value means that the acid is stronger. This value can be useful when comparing relative strength of acids between two weak acids.
by ALegala_2I
Mon Jan 13, 2020 9:53 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Example 5I.3 (page 556 on pdf)
Replies: 3
Views: 25

Re: Example 5I.3 (page 556 on pdf)

Does this removal of x in the expression depend on the value of K?
by ALegala_2I
Mon Jan 13, 2020 9:51 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Change in Pressure
Replies: 6
Views: 33

Re: Change in Pressure

When the pressure decreases, the volume increases as they are inversely proportional. This means that the concentration also decreases and to bring the system back to equilibrium, the reaction which creates more moles will be favored.
by ALegala_2I
Wed Jan 08, 2020 9:14 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure changes to equilibrium equations
Replies: 5
Views: 87

Re: Pressure changes to equilibrium equations

How does the increasing the pressure of a gas like Helium, which is not active in the chemical equation, affect equilibrium?
by ALegala_2I
Wed Jan 08, 2020 9:11 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: 5H.3
Replies: 2
Views: 24

Re: 5H.3

I believe it is referring to this chart.
[img]Screen%20Shot%202020-01-03%20at%207.53.41%20PM[/img]
by ALegala_2I
Tue Jan 07, 2020 11:35 am
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Using the "ICE" box
Replies: 8
Views: 98

Re: Using the "ICE" box

Solids and liquids are not included because there is generally a large amount of it. This generally does not affect the reactants or products which is why it is left out of the ICE table calculations.
by ALegala_2I
Mon Jan 06, 2020 4:51 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: The Significance of K
Replies: 5
Views: 52

The Significance of K

When do you use Kc vs Kp?
by ALegala_2I
Mon Jan 06, 2020 4:50 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium Constant
Replies: 4
Views: 40

Re: Equilibrium Constant

K tells you the proportion of products to reactants present in the reaction and whether there are more products or reactants. When a certain reaction is strongly favored, it means that the K value is greater than 1000.
by ALegala_2I
Wed Dec 04, 2019 9:59 am
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Bronsted vs Arrhenius Base: J.1(c) and (e)
Replies: 3
Views: 151

Re: Bronsted vs Arrhenius Base: J.1(c) and (e)

The OH- in both compounds with accept a proton to create water. Since it is accepting protons, these compounds conform to the definition of a Bronsted base.
by ALegala_2I
Wed Dec 04, 2019 9:57 am
Forum: Amphoteric Compounds
Topic: Amphoteric vs Amphiprotic
Replies: 9
Views: 99

Re: Amphoteric vs Amphiprotic

What does the term polyprotic mean? Can a molecule be both polyprotic and amphiprotic?
by ALegala_2I
Tue Dec 03, 2019 9:42 am
Forum: Conjugate Acids & Bases
Topic: 6A.1
Replies: 6
Views: 140

Re: 6A.1

For a conjugate base, you remove a hydrogen and add a 1- charge.
by ALegala_2I
Mon Dec 02, 2019 11:31 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Water as a acid or base
Replies: 4
Views: 70

Re: Water as a acid or base

Water can only be labeled as an acid or a base depending on the reaction. In some cases, it may act as an acid and donate a hydrogen, In other cases, it may act as a base and accept protons. Water has a set constant, Kw, which is 1.01 × 10^-14 at 25 °C.
by ALegala_2I
Mon Dec 02, 2019 11:21 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Relative Acidity
Replies: 2
Views: 40

Re: Relative Acidity

For binary acids, the atom with a greater radius will be more acidic because it can easily give off an H+ ion. For example, HI is a stronger acid than HF. For oxoacids, the molecule with the greatest amount of oxygens is the most acidic. This is due to the fact the it increases electronegativity, ma...
by ALegala_2I
Wed Nov 27, 2019 10:37 am
Forum: Amphoteric Compounds
Topic: Question 6A.11
Replies: 5
Views: 140

Re: Question 6A.11

HCO3- and HPO4 2- can both accept and donate protons. In this way, they are considered amphiprotic and can be used as an acid or a base in the reaction. If they are an acid, they lose the hydrogen in the reaction. If they are basic, they gain a hydrogen in the reaction.
by ALegala_2I
Tue Nov 26, 2019 1:44 pm
Forum: Naming
Topic: Naming coordination compound
Replies: 5
Views: 74

Re: Naming coordination compound

This coordinate compound is bisethylenediamine dinitro iron (IV) sulfate.
by ALegala_2I
Tue Nov 26, 2019 1:36 pm
Forum: Lewis Acids & Bases
Topic: Lewis vs Bronsted Acids and Bases
Replies: 3
Views: 30

Re: Lewis vs Bronsted Acids and Bases

Lewis and Bronsted Acids and Bases are simply different because of how they define and acid and a base. In Bronsted's definition, an acid is a proton donor and a base is a proton acceptor. In the Lewis definition, an acid is an electron pair acceptor and a base is an electron pair donor. The Lewis t...
by ALegala_2I
Mon Nov 25, 2019 11:35 am
Forum: Naming
Topic: Correct naming conventions
Replies: 5
Views: 63

Correct naming conventions

When do you add the suffix -ate to the metal name in a coordination compound?
by ALegala_2I
Mon Nov 25, 2019 11:34 am
Forum: Naming
Topic: 9C.3d
Replies: 1
Views: 25

Re: 9C.3d

I believe that the parentheses are present to be able to identify the molecules in the coordination compound. It is just for ease of reading not a special purpose.
by ALegala_2I
Wed Nov 20, 2019 8:57 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs for AX4E
Replies: 3
Views: 47

Lone Pairs for AX4E

For a seesaw shaped molecule, how do you know that the lone pair should be on the equatorial plane and not the axial plane?
by ALegala_2I
Tue Nov 19, 2019 12:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw shape
Replies: 1
Views: 27

Re: Seesaw shape

In the seesaw shape, the bond angles will be <90, <120, and <180.

Image
by ALegala_2I
Tue Nov 19, 2019 9:21 am
Forum: Hybridization
Topic: Stability of bonds
Replies: 3
Views: 34

Re: Stability of bonds

Sigma bonds are also more flexible than pi bonds because of their orientation to the atom. Pi bonds do not allow rotation and they are usually the first bonds broken down in a chemical reaction.
by ALegala_2I
Mon Nov 18, 2019 1:14 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR, Molecular Geometry, and Molecular Shape
Replies: 4
Views: 85

Re: VSEPR, Molecular Geometry, and Molecular Shape

The VSEPR model gives you the electron geometry and molecular shape. The electron geometry of a molecule is the naming convention based on the number of electron regions. Molecules with 2 electron regions are linear, 3 electron regions are trigonal planar, 4 electron regions are tetrahedral, 5 elect...
by ALegala_2I
Mon Nov 18, 2019 1:02 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AXE notation
Replies: 10
Views: 111

Re: AXE notation

The AXE notation is useful to organize the types of electron regions in a molecule. For example, SF4 has a seesaw shape. This means it has four bonds and 1 lone pair. This can be described as AX4E in the notation.
by ALegala_2I
Wed Nov 13, 2019 11:39 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: intermolecular forces
Replies: 8
Views: 141

Re: intermolecular forces

Dipoles occur when there is an unequal sharing of electrons. Each atom in a molecule has a partial charge which is either negative or positive. When one charge is significantly larger than another, or the electronegativity difference is great, a dipole is produced. Lone pairs on the central atom als...
by ALegala_2I
Wed Nov 13, 2019 9:08 am
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 and Dipole-Dipole
Replies: 5
Views: 85

Re: London Forces and Dipole-Dipole

London Dispersion forces act on all molecules and atoms. This includes nonpolar molecules, monoatomic gases, and in molecules that also exhibit dipole-dipole interactions.
by ALegala_2I
Tue Nov 12, 2019 9:01 am
Forum: Dipole Moments
Topic: 3f.15
Replies: 3
Views: 67

Re: 3f.15

According to the problem, the boiling point of AsF3 is 68C and AsF5 is -53. You can first approach this problem by drawing the Lewis structures for both molecules to find out the intermolecular forces that each molecule has. AsF3 has a lewis structure in which a lone pair on the Arsenic atom. This m...
by ALegala_2I
Tue Nov 12, 2019 8:51 am
Forum: Dipole Moments
Topic: 3F.11
Replies: 3
Views: 47

Re: 3F.11

Hydrogen bonds form when hydrogen interacts with nitrogen, oxygen, or fluorine. In this problem, only d can create hydrogen bonds because it has nitrogen and oxygen.
by ALegala_2I
Mon Nov 11, 2019 11:31 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: Induced Dipole/ Induced Dipole
Replies: 4
Views: 42

Re: Induced Dipole/ Induced Dipole

London Dispersion forces are known as induced-dipole–induced-dipole interaction. Interactions that are proportional to 1/r6 are commonly regarded as van der Waals interactions. So London Dispersion forces are a type of van der Waals interaction.
by ALegala_2I
Wed Nov 06, 2019 8:15 am
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 2
Views: 43

Re: Formal Charge

Electronegativity is the electron pulling power of an atom. The atoms that are more electronegative will want the electron more in real life. The negative formal charge indicates an excess of an electron. Since more electronegative atoms will have a greater power to pull this electron, they will gen...
by ALegala_2I
Tue Nov 05, 2019 9:12 am
Forum: Lewis Structures
Topic: 2C.9
Replies: 1
Views: 40

Re: 2C.9

Sulfur is one of the exceptions that Dr. Lavelle mentioned in terms of being able to have an expanded octet. It can bond to 6 atoms and have an expanded octet with 12 electrons.
by ALegala_2I
Tue Nov 05, 2019 9:08 am
Forum: Bond Lengths & Energies
Topic: 2D.9
Replies: 1
Views: 28

Re: 2D.9

The Question for 2.D.9: Arrange the cations Rb+1, Be+2, and Sr+2 in order of increasing polarizing power. Explain your reasoning. The cations with the smallest radius and largest charge have the greatest polarizing power. Of the three, beryllium has the smallest radius, so it would have the greatest...
by ALegala_2I
Mon Nov 04, 2019 9:04 am
Forum: Electronegativity
Topic: Trend of Electronegativity
Replies: 22
Views: 414

Re: Trend of Electronegativity

Electronegativity is the electron pulling power of an atom. As you move to the right of the periodic table, the electronegativity increases because atoms get closer and closer to having a full octet. As you move up the periodic table, electronegativity also increases because there is less shielding ...
by ALegala_2I
Mon Nov 04, 2019 9:00 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Trends
Replies: 3
Views: 76

Re: Trends

Cations with a smaller radius and a more positive charge have greater polarizing power. For example, K+ > K in polarizing power. Anions with a larger radius and a more negative charge have greater polarizability because they have more electrons. So I->Br-, in polarizability.
by ALegala_2I
Wed Oct 30, 2019 7:39 pm
Forum: Resonance Structures
Topic: Determining the Pairing for Lewis Structures
Replies: 2
Views: 44

Determining the Pairing for Lewis Structures

How do we know when the hydrogen will be attached to the central atom vs other atoms? Like in the case of HClO2, why is the hydrogen attached to the oxygen and not the chlorine? https://img1.daumcdn.net/thumb/R720x0.q80/?scode=mtistory2&fname=http%3A%2F%2Fcfile7.uf.tistory.com%2Fimage%2F999FF54C...
by ALegala_2I
Wed Oct 30, 2019 7:34 pm
Forum: Lewis Structures
Topic: Radicals
Replies: 2
Views: 31

Re: Radicals

Radicals are fairly uncommon because they are highly unstable and reactive. They will generally only stay in that form for a short period of time before interacting with other molecules to get a pair.
by ALegala_2I
Tue Oct 29, 2019 2:03 pm
Forum: Ionic & Covalent Bonds
Topic: Octet Rule
Replies: 8
Views: 107

Re: Octet Rule

Professor Lavelle said that phosphorus, sulfur, and chlorine can have expanded octets. This is due to the fact that they have empty p orbitals which can accommodate additional electrons.
by ALegala_2I
Tue Oct 29, 2019 2:00 pm
Forum: Ionic & Covalent Bonds
Topic: Homework 2A.21
Replies: 1
Views: 32

Re: Homework 2A.21

Ag is one of the exceptions to the build up principle. It would normally have a configuration of [Kr]4d10 5s1 because the atom would be most stable when the d shell is completely full rather than the s shell. When you remove an electron from Ag, it will be removed from the outermost shell which is 5...
by ALegala_2I
Mon Oct 28, 2019 7:32 pm
Forum: Lewis Structures
Topic: Homework problem 2C.3
Replies: 5
Views: 57

Re: Homework problem 2C.3

As of right now, I believe that we do not need to memorize the molecular formula for these molecules since we did not cover it in class. On a test, I think it would be given to us and we would just have to draw the lewis structure.
by ALegala_2I
Mon Oct 28, 2019 7:29 pm
Forum: Ionic & Covalent Bonds
Topic: ionic bonding 2A.13
Replies: 1
Views: 26

Re: ionic bonding 2A.13

Chlorine has the ground state electron configuration of [Ne]3s1 3p5. An electron is always removed from the outermost subshell present. In this case, the outermost subshell is 3p.
by ALegala_2I
Wed Oct 23, 2019 9:02 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: 1D.23
Replies: 2
Views: 63

Re: 1D.23

For b and d, you would go off of the ml number. In a 4p atom in which l=1, there are 3 possibly orbitals orientations as stated above. This means that an electron in the 4p orbital could have the following configurations: n=4, l=1, ml = 1; n=4, l=1, ml = 0, and n=4, l=1, ml = -1. When you are given ...
by ALegala_2I
Tue Oct 22, 2019 8:23 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Aufbau principle
Replies: 2
Views: 21

Re: Aufbau principle

Aufbau principle is just rules for how electrons fill atomic orbitals. It states that electrons will always fill the lowest energy state first. For example, an electron will be in the 1s orbital before the 2s orbital. It also states that electrons will be added to different orbitals with parallel sp...
by ALegala_2I
Tue Oct 22, 2019 8:47 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations for electrons in the D subshell
Replies: 5
Views: 69

Re: Electron Configurations for electrons in the D subshell

This filling of the d orbital over the s orbital will also occur for elements such as chromium. Instead of being [Ar]3d44s2, the electron configuration will be [Ar]3d54s1.
by ALegala_2I
Mon Oct 21, 2019 8:53 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Exceptions in Electron Configurations
Replies: 5
Views: 50

Re: Exceptions in Electron Configurations

Do all the elements in group 6 and 11 have electron configurations similar to copper and chromium?
by ALegala_2I
Mon Oct 21, 2019 8:48 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: terminology - "orbitals", "shells", "subshells"
Replies: 2
Views: 24

Re: terminology - "orbitals", "shells", "subshells"

The principal quantum number (n) specifies the shell of the electrons in an atom. For example, 4p corresponds to 4 shells of electrons in the atom. The angular momentum number (l) signifies the sub-shells. The magnetic quantum number describes the amount of orbitals in a sub shell. There are 3 orbit...
by ALegala_2I
Wed Oct 16, 2019 7:50 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Which equation to use for determining uncertainty?
Replies: 4
Views: 43

Which equation to use for determining uncertainty?

Hi, In the textbook, a modified equation for the uncertainty principle is used with the variable h bar (see below). What does this variable signify? Which equation should we use: the one from the textbook or the one that is taught in class? https://scitechdaily.com/images/heisenberg-uncertainty-prin...
by ALegala_2I
Tue Oct 15, 2019 7:58 am
Forum: DeBroglie Equation
Topic: de Broglie vs Heisenberg
Replies: 2
Views: 41

Re: de Broglie vs Heisenberg

To add on, the Heisenberg equation is specifically used in regards to uncertainty. The questions will usually ask you what the uncertainty in the velocity is or it will give you a range of values for velocity. This is your main indicator to use the Heisenberg equation over the deBroglie equation.
by ALegala_2I
Mon Oct 14, 2019 8:19 pm
Forum: DeBroglie Equation
Topic: DeBroglie
Replies: 3
Views: 43

Re: DeBroglie

DeBroglie's proposed that all particles should be considered to have wave like properties. So he devised the equation: wavelength(lambda) = Planck's constant(h)/ momentum(p). In this equation, we are treating light like a wave and finding the wavelength based on the mass and velocity of the particle.
by ALegala_2I
Mon Oct 14, 2019 8:16 am
Forum: Einstein Equation
Topic: Einstein Equation
Replies: 4
Views: 99

Re: Einstein Equation

You use the equation E=hv when you are trying to find out the energy of a photon of light. If you know the frequency of this photon, then you can multiply it by Planck's constant to find the total energy of the photon.
by ALegala_2I
Mon Oct 14, 2019 8:13 am
Forum: Properties of Light
Topic: Memorizing Values for Tests
Replies: 3
Views: 26

Re: Memorizing Values for Tests

The values of c (speed), Planck's constant, and Rydberg's constant are on the formula sheet, which will be given to you for every exam.
by ALegala_2I
Wed Oct 09, 2019 2:13 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Light energy
Replies: 3
Views: 75

Re: Light energy

I think it will be helpful to know which types of light have the largest wavelengths and the shortest. For example, radio waves have the greatest wavelength while gamma rays of the shortest. It will essentially be beneficial to know the order. https://www.radio2space.com/wp-content/uploads/2013/07/c...
by ALegala_2I
Wed Oct 09, 2019 9:22 am
Forum: Empirical & Molecular Formulas
Topic: Molecular formula
Replies: 6
Views: 692

Re: Molecular formula

To clarify, when you divide by the least number of moles. The answer you are getting is a molar ratio of atoms in the molecule. This is relative to the other atoms in the molecule. We want this ratio to be a whole number because we can only have a whole number of atoms. To find the molecular formula...
by ALegala_2I
Tue Oct 08, 2019 11:11 am
Forum: Properties of Light
Topic: Light intensity
Replies: 6
Views: 96

Re: Light intensity

In terms of wave properties, higher intensity means a greater wave amplitude and therefore a greater amount of energy. In the photoelectric experiment, it was found that increasing the intensity of light did not increase the energy of light. So this experiment supported the idea that light did not h...
by ALegala_2I
Mon Oct 07, 2019 11:08 am
Forum: SI Units, Unit Conversions
Topic: Angstrom(Å)
Replies: 4
Views: 71

Re: Angstrom(Å)

An angstrom is not a SI unit. It is used and recognized by many scientists but it is not part of the International System. An angstrom represents 10^-10m. This can be converted to other SI units like nanometers or picometers.
by ALegala_2I
Mon Oct 07, 2019 11:05 am
Forum: SI Units, Unit Conversions
Topic: Molar Ratio
Replies: 4
Views: 121

Re: Molar Ratio

To clarify the statement above, a molar ratio refers to BOTH the stoichemetric coefficients in a chemical equation and the moles of atoms in a molecule. For example, the chemical equation C2H4 + 3O2 → 2CO2 + 2H2O. There is a molar ratio of 2 water molecules to 2 carbon dioxide molecules. Within the ...
by ALegala_2I
Wed Oct 02, 2019 9:28 am
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Tips on how to write a formula out from the name
Replies: 9
Views: 209

Re: Tips on how to write a formula out from the name

There are several polyatomic ions which are good to memorize. There is a list of nomenclature in the beginning of the book which can be useful for future problems.
by ALegala_2I
Tue Oct 01, 2019 11:49 am
Forum: Balancing Chemical Reactions
Topic: Tips for Balancing Chemical Equations [ENDORSED]
Replies: 14
Views: 248

Re: Tips for Balancing Chemical Reactions [ENDORSED]

I would first write down the number of atoms of each element that is present for the reactant side and the product side. I would then begin to balance my equation and typically leave hydrogen and oxygen for the end. As I balance, I would readjust the initial numbers that were written at the beginnin...
by ALegala_2I
Mon Sep 30, 2019 7:53 pm
Forum: Significant Figures
Topic: How to Write Out Final Answers
Replies: 5
Views: 84

Re: How to Write Out Final Answers

Both 9.87 mL and 9.87 x 10^-3 L have the same value. Regardless of how it is written, the amount that would be measured for the actual experiment would be the same. If the question asks you for the volume in a specific measurement then you would have to choose one or the other.
by ALegala_2I
Sun Sep 29, 2019 2:33 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula
Replies: 6
Views: 83

Re: Empirical Formula

While the empirical and molecular formulas can be different, there are situations in which the two formulas are the same. This can be determined by dividing the molar mass of the molecular formula by the molar mass of the empirical formula. If the ratio is 1, the empirical and molecular formulas for...

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