Search found 96 matches

by Deepika Reddy 1A
Mon Feb 17, 2020 2:03 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Buffer Solution
Replies: 4
Views: 18

Re: Buffer Solution

Buffer solutions can only be made with a weak acid and its conjugate base or a weak base and its conjugate acid. This is because a strong acid or strong base completely dissociate in a solution so that at the end, none of the substance is present in the solution at the end of the reaction. For weak ...
by Deepika Reddy 1A
Mon Feb 17, 2020 1:52 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Reversible and Irreversible
Replies: 2
Views: 12

Re: Reversible and Irreversible

An irreversible reaction is one where the pressure remains constant. The second law of thermodynamics states that the entropy of the surroundings always increases. This would apply to irreversible reactions. However, entropy remains constant with reversible reactions because only infinitesimally sma...
by Deepika Reddy 1A
Mon Feb 17, 2020 1:43 pm
Forum: Balancing Redox Reactions
Topic: Oxidizing/Reducing Agents
Replies: 2
Views: 7

Re: Oxidizing/Reducing Agents

Oxidizing agents are substances that cause other substances to become oxidized which causes themselves to be reduced. For reducing agents, they themselves are oxidized and they cause other substances to be reduced. The main thing to remember is that these names are indicating what these substances a...
by Deepika Reddy 1A
Mon Feb 17, 2020 1:36 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Free Energy and Work
Replies: 3
Views: 8

Re: Free Energy and Work

Free energy is the energy that is available to do work.
by Deepika Reddy 1A
Mon Feb 17, 2020 1:34 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: G vs G knot
Replies: 10
Views: 21

Re: G vs G knot

G knot indicates that the substances in the equation are all in their standard or most pure states. You will get different answers when solving for either G or G knot but they can be related using the equation mentioned before in another answer.
by Deepika Reddy 1A
Mon Feb 17, 2020 1:28 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Open Systems
Replies: 6
Views: 18

Re: Open Systems

I agree. Open systems are able to exchange matter and energy with its surroundings. I think the important thing is looking at whether the pressure is constant or not or if the volume is constant or not in deciding what equations to use.
by Deepika Reddy 1A
Sun Feb 09, 2020 11:09 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: specific heat v.s molar heat
Replies: 2
Views: 7

Re: specific heat v.s molar heat

Specific heat is in terms of grams while molar heat is in terms of moles. Specific heat is the heat capacity divided by mass in grams while molar heat is heat capacity divided by the moles.
by Deepika Reddy 1A
Sun Feb 09, 2020 7:43 pm
Forum: Phase Changes & Related Calculations
Topic: 12B on Pizza Rolls Review Packet
Replies: 1
Views: 45

Re: 12B on Pizza Rolls Review Packet

Enthalpy is a state function which means that only the initial and final enthalpy values matter. The pathway taken does not matter. Therefore, because we know the enthalpy for the reaction at 200 degrees C, we make the pathway in a way where the initial and final would still be the same but it will ...
by Deepika Reddy 1A
Sun Feb 09, 2020 7:39 pm
Forum: Ideal Gases
Topic: Change in pressure
Replies: 7
Views: 20

Re: Change in pressure

If you increase the pressure of the reaction, the reaction will shift to the side with fewer moles of gas. If you decrease the pressure of the reaction, the reaction will shift to the side with the greater number of moles of gas. A change in pressure causes a shift in the reaction because it alters ...
by Deepika Reddy 1A
Sun Feb 09, 2020 7:36 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy at 0 Kelvin
Replies: 3
Views: 17

Re: Entropy at 0 Kelvin

I believe they explained this in the pizza rolls review session. They said that even if molecules are at 0 Kelvin, they still have positional entropy. In order to have no entropy, the molecule at 0 K has to be perfectly ordered.
by Deepika Reddy 1A
Sun Feb 09, 2020 9:50 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: monoatomic, diatomic, linear, non-linear
Replies: 3
Views: 18

Re: monoatomic, diatomic, linear, non-linear

I believe the shape affects how many different shapes or positions the atoms in the molecule can be in. Since entropy is associated with the number of states or positions the atoms in a molecule can take, the shape of the molecule is associated with entropy.
by Deepika Reddy 1A
Sun Feb 09, 2020 3:24 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Internal Energy as State Function
Replies: 1
Views: 17

Re: Internal Energy as State Function

The volume is expanding in b but it is expanding in a vacuum. What this means is that the external pressure is zero, so there is no force that is opposing the expansion being doing by the system. Work is only done when there is an opposing force that needs to be pushed against. Since there is no opp...
by Deepika Reddy 1A
Sun Feb 09, 2020 3:21 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Units for Reaction Enthalpy
Replies: 1
Views: 7

Re: Units for Reaction Enthalpy

I believe the standard reaction enthalpy should always be in kJ/mol. If it is just the enthalpy value, it is in kJ.
by Deepika Reddy 1A
Mon Feb 03, 2020 12:30 am
Forum: Calculating Work of Expansion
Topic: Reversible
Replies: 7
Views: 14

Re: Reversible

Equilibrium means that it is a dynamic equilibrium and a reaction is occurring in the forward and reverse directions. Therefore, if it is at equilibrium, it is reversible.
by Deepika Reddy 1A
Mon Feb 03, 2020 12:27 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: state functions
Replies: 10
Views: 29

Re: state functions

State functions are when you only care about the initial and final values but the path taken to get to these values is not important.
by Deepika Reddy 1A
Mon Feb 03, 2020 12:13 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Universe Closed System
Replies: 3
Views: 10

Re: Universe Closed System

The system does not exchange matter with the surroundings if it is a closed system.
by Deepika Reddy 1A
Mon Feb 03, 2020 12:09 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: taking phase change into account
Replies: 5
Views: 15

Re: taking phase change into account

A phase change can be between solids and liquids or liquids and gases. It takes a certain amount of energy for the phase to change.
by Deepika Reddy 1A
Mon Feb 03, 2020 12:06 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: enthalpy
Replies: 7
Views: 27

Re: enthalpy

Enthalpy is the heat of the reaction. If it is negative, then the reaction is exothermic. If it is positive, then the reaction is endothermic.
by Deepika Reddy 1A
Sun Feb 02, 2020 8:21 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Test 1
Replies: 6
Views: 24

Re: Test 1

If Q is smaller than K, then equilibrium will shift towards the right so that it makes more products and Q will equal K. If Q is larger than K, then the reaction will shift towards the reactants so that more reactants can be made in order to reach equilibrium.
by Deepika Reddy 1A
Sun Feb 02, 2020 8:20 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Shifts
Replies: 5
Views: 19

Re: Shifts

It depends on what is changing in the reaction. If the number of moles are changing, the rxn will shift a certain way in order to get the system back to equilibrium. If the product is taken away, then equilibrium will shift towards the products and if product is added, equilibrium will shift towards...
by Deepika Reddy 1A
Sun Jan 26, 2020 3:56 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: exo thermic
Replies: 11
Views: 22

Re: exo thermic

In an exothermic reaction, the heat is on the products side of the reaction since the reaction is releasing heat. Therefore, when you increase the heat, the reactant side will be favored and the equilibrium will shift to the left.
by Deepika Reddy 1A
Sun Jan 26, 2020 3:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE
Replies: 20
Views: 70

Re: ICE

You usually have to use the ICE table when you only have the initial concentrations or you need to calculate the equilibrium concentrations. If Ka or Kb are given with some concentrations, then you are usually using the ICE table and the Ka or Kb values to find any missing concentrations.
by Deepika Reddy 1A
Sun Jan 26, 2020 3:49 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy & Spontaneity
Replies: 4
Views: 14

Re: Enthalpy & Spontaneity

If the reaction has a positive enthalpy, then it is endothermic and is non -spontaneous as it requires heat in order to occur. If the reaction has a negative enthalpy, then it is exothermic and is spontaneous.
by Deepika Reddy 1A
Sun Jan 26, 2020 3:44 pm
Forum: Phase Changes & Related Calculations
Topic: Enthalpy w/ Temp
Replies: 6
Views: 20

Re: Enthalpy w/ Temp

If a reaction loses heat so that the products have less heat than the reactants, then the enthalpy is negative. If a reaction gains heat in order to occur, then the enthalpy is positive.
by Deepika Reddy 1A
Sun Jan 26, 2020 3:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: protonization/ionization
Replies: 4
Views: 20

Re: protonization/ionization

You find the percent by putting the concentration of the conjugate acid or base over the initial concentration of the acid or base and then multiplying by 100 to get the percentage.
by Deepika Reddy 1A
Sun Jan 19, 2020 10:18 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: K less than 10^-3
Replies: 5
Views: 15

Re: K less than 10^-3

If K is less than 10^-3, that means that the reaction favors the reactants at equilibrium. This means that there are more reactants than products at equilibrium so barely any of the reactants turned into product as the reaction proceeded.
by Deepika Reddy 1A
Sun Jan 19, 2020 10:16 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Weak acids & bases
Replies: 7
Views: 23

Re: Weak acids & bases

You do the concentration of the conjugate over the concentration of the acid or base and then multiply by 100%.
by Deepika Reddy 1A
Sun Jan 19, 2020 10:13 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Effect of increasing pressure on reactions
Replies: 6
Views: 17

Re: Effect of increasing pressure on reactions

If the pressure is increased, then the reaction favors the side of the reaction that has fewer moles of gas. In class, he gave us C=n/V and said that the change in concentration caused by the change in volume is what affects the reaction.
by Deepika Reddy 1A
Sun Jan 19, 2020 1:44 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Different Values for K and Kc?
Replies: 3
Views: 18

Re: Different Values for K and Kc?

The table is using K to represent Kp. For the reactions that the Kc and K values are the same, the moles of gas on both sides of the reaction is probably equal. This would mean that Kc=Kp, so therefore in the table, K is equal to Kc for those reactions.
by Deepika Reddy 1A
Sun Jan 19, 2020 1:41 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: 5% vs. K < 10^-3
Replies: 3
Views: 19

Re: 5% vs. K < 10^-3

They are the same rule. If you disregard the x because K is less than 10^-3, at the end you can also check if it corresponds to the 5% rule. If it does follow the 5% rule, this means that the substance barely dissociates so K is small so it was correct to disregard x.
by Deepika Reddy 1A
Sat Jan 18, 2020 1:37 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: Strength of an Acid/Base
Replies: 2
Views: 18

Re: Strength of an Acid/Base

Ka is the equilibrium constant for an acid reaction while Kb is the equilibrium constant for a base reaction. Ka is related to pKa because pKa= -log(Ka) while pKb is related to Kb because pKb =-log(Kb). The larger the value of Ka, the stronger the acid and the larger the value of Kb, the stronger th...
by Deepika Reddy 1A
Sun Jan 12, 2020 11:20 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: When is the principle helpful?
Replies: 3
Views: 9

Re: When is the principle helpful?

Le Chatelier's Principle is helpful because it shows us how a reaction gets back to equilibrium after it has been changed in some way that causes it to not be at equilibrium anymore. This is helpful because it allows us to predict whether the reaction will favor the products or the reactants in orde...
by Deepika Reddy 1A
Sun Jan 12, 2020 11:11 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Kc
Replies: 3
Views: 12

Re: K vs Kc

The K and Kc values are the same things. Therefore, there is no conversion you need to do between the two. I believe they will specify Kp if it is the one being used.
by Deepika Reddy 1A
Sun Jan 12, 2020 10:58 am
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: changing conditions
Replies: 6
Views: 18

Re: changing conditions

When you take away a product you are stressing the reaction and shifting it away from equilibrium. In order for it to return to equilibrium, the reaction needs to make enough product again for the reaction to return to the same equilibrium K value. Therefore, by taking away a product, the reaction n...
by Deepika Reddy 1A
Sat Jan 11, 2020 4:40 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Significance of principle
Replies: 6
Views: 20

Re: Significance of principle

Le Chatelier's principle predicts how a change in the physical parameters and other factors in a system affects a reaction and makes it no longer at equilibrium. It predicts whether the reactants or products will be favored in order for the reaction to go back to equilibrium.
by Deepika Reddy 1A
Sat Jan 11, 2020 4:33 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Changes in Pressure
Replies: 3
Views: 26

Re: Changes in Pressure

It has to do with the equation C=n/V. This equation shows that if the volume is changed then the concentrations also change. For example, when the volume is halved and the pressure is doubled, the concentration of the reactants and products changes. This causes the reaction to no longer be at equili...
by Deepika Reddy 1A
Sun Dec 08, 2019 11:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AXE formula
Replies: 7
Views: 46

Re: AXE formula

The E on the AXE is just the lone pairs on the central atom.
by Deepika Reddy 1A
Sun Dec 08, 2019 11:25 pm
Forum: Naming
Topic: "Ferrate"
Replies: 14
Views: 137

Re: "Ferrate"

When the complex ion is an anion, then you have to add -ate to the end of the transition metal name. Some of the metals have exceptions, and have ate added a different way which just has to be memorized.
by Deepika Reddy 1A
Sun Dec 08, 2019 8:59 pm
Forum: Amphoteric Compounds
Topic: As2O and Bi2O3
Replies: 4
Views: 34

Re: As2O and Bi2O3

I think you just have to memorize the diagonal trend in the periodic table. The metals and oxides formed by some of these elements are amphoteric.
by Deepika Reddy 1A
Sun Dec 08, 2019 8:50 pm
Forum: Administrative Questions and Class Announcements
Topic: Saying Thank You to Dr. Lavelle
Replies: 229
Views: 104419

Re: Saying Thank You to Dr. Lavelle

Dr. Lavelle, I hated chemistry before your class but you made the topics fun to learn and easy to understand. There were so many resources if we needed help too, which is something a lot of other classes don't have. This was my first quarter at UCLA and I'm so glad I took this class. I'm so excited ...
by Deepika Reddy 1A
Sun Dec 08, 2019 8:40 pm
Forum: Lewis Acids & Bases
Topic: What does it mean when something is strong?
Replies: 8
Views: 54

Re: What does it mean when something is strong?

Strong acids and strong bases are substances that completely dissociate in water. Their conjugates are unreactive and are unable to reform the acid or base.
by Deepika Reddy 1A
Sun Dec 08, 2019 8:28 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: boiling point
Replies: 8
Views: 41

Re: boiling point

The stronger the IMFs, the higher the boiling point. For example, it takes more energy to break dipole-dipole IMFs than to break London dispersion IMFs because dipole dipole forces are stronger. Therefore, by looking at the IMFs, we can predict which substances have a higher boiling point.
by Deepika Reddy 1A
Sun Dec 08, 2019 8:23 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Stronger acid?
Replies: 9
Views: 80

Re: Stronger acid?

HClO2 is the stronger acid because it has more oxygens. The oxygens make the conjugate base, or anion, more stable. This is because of resonance, where the negative charge on the oxygen delocalizes over the entire molecule, which stabilizes it.
by Deepika Reddy 1A
Sun Dec 08, 2019 8:09 pm
Forum: Lewis Acids & Bases
Topic: bases
Replies: 5
Views: 45

Re: bases

A strong base is a hydroxide or oxide of the Group 1 or Group 2 metals. It dissociates almost completely in water, producing a lot of hydroxide ions. It causes the pH to rise a lot. A weak base only partially dissociates and causes less of a change in the pH.
by Deepika Reddy 1A
Sat Dec 07, 2019 12:32 am
Forum: Hybridization
Topic: 2s for Carbon hybridization
Replies: 3
Views: 21

Re: 2s for Carbon hybridization

For hybridization, you look at the valence electrons of the carbon because those are the ones that take part in bonding. So, since the valence electrons in carbon are in the second energy level, the hybridized orbitals have the number two written in front of them.
by Deepika Reddy 1A
Sun Dec 01, 2019 8:12 pm
Forum: Lewis Acids & Bases
Topic: Arrhenius Acids & Bases
Replies: 2
Views: 29

Re: Arrhenius Acids & Bases

I'm not completely sure if we have to know Arrhenius acids or bases, but Arrhenius acids are just substances that dissociate into protons in the water. Arrhenius bases are substances that dissociate into hydroxide ions in water.
by Deepika Reddy 1A
Sun Dec 01, 2019 8:05 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Coordination Number
Replies: 4
Views: 23

Re: Coordination Number

Yes, I believe that the coordination number is the number of points at which a ligand is attached to a central atom.
by Deepika Reddy 1A
Sun Dec 01, 2019 8:01 pm
Forum: Hybridization
Topic: Hybridization (Lone Pairs)
Replies: 4
Views: 34

Re: Hybridization (Lone Pairs)

Yes, I think they do. By counting then number of lone pairs and bonding regions, I believe it is possible to figure out the hybridization. For example, for seesaw I believe it would be dsp3.
by Deepika Reddy 1A
Sat Nov 30, 2019 12:03 pm
Forum: Bronsted Acids & Bases
Topic: Net Ionic Equations
Replies: 5
Views: 33

Re: Net Ionic Equations

I believe that you would have to know the solubility rules. If something is soluble, then it shows up as ions. If the solubility rules says that a molecule or compound is not soluble, then the molecule or compound is written together and not dissociated into ions.
by Deepika Reddy 1A
Sat Nov 30, 2019 2:40 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Difference between Arrhenius, Bronsted, and Lewis
Replies: 5
Views: 37

Re: Difference between Arrhenius, Bronsted, and Lewis

A Lewis Acid is one that accept an electron pair while a Lewis base is one that can donate an electron pair. A Bronsted acid is one that donates protons while a Bronsted base is one that accepts protons. Finally, an Arrhenius acid is a substance that dissolves to increase the number of protons in wa...
by Deepika Reddy 1A
Sun Nov 24, 2019 11:49 pm
Forum: Bond Lengths & Energies
Topic: Boiling Point
Replies: 4
Views: 42

Re: Boiling Point

Boiling point can be determined by looking at the strongest intermolecular force that a substance has. If it has a stronger intermolecular force, then it has a higher boiling point. If both substances have london dispersion forces as their strongest IMF, then look at the size of the molecules and th...
by Deepika Reddy 1A
Sun Nov 24, 2019 5:12 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 12
Views: 77

Re: Electronegativity

The higher the electronegativity, the closer the bond gets to being an ionic bond. Ionic bonds are stronger than covalent bonds. Therefore, this tells us that the higher the electronegativity is, the more the atoms are attracted to each other. The higher the electronegativity, the stronger and short...
by Deepika Reddy 1A
Sun Nov 24, 2019 5:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole Moment?
Replies: 4
Views: 24

Re: Dipole Moment?

If the dipole moments cancel out, then most of the time that means that there is symmetry. Dipole moments occur when atoms do not share their electrons equally, causing the electrons to be pulled one way. If dipole moments cancel out, then the molecule is nonpolar. If they do not, then the molecule ...
by Deepika Reddy 1A
Sun Nov 24, 2019 11:55 am
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Transition Metals
Replies: 3
Views: 27

Re: Transition Metals

I believe that a majority of the time, only transition metals are able to form coordination compounds and are the central atoms of them. This is because they normally do not make bonds like the main group atoms do. Main group atoms will normally form covalent or ionic bonds, however it is sometimes ...
by Deepika Reddy 1A
Sun Nov 24, 2019 11:42 am
Forum: Lewis Acids & Bases
Topic: Acid and Base Strength
Replies: 7
Views: 41

Re: Acid and Base Strength

A strong acid and base reaction will have equilibrium lie far to the right because they both dissociate almost completely into products. This means that at the end of the reaction, there will be more products than reactants. A weak acid and base will have equilibrium lie far to the left and at the e...
by Deepika Reddy 1A
Fri Nov 22, 2019 9:07 am
Forum: Dipole Moments
Topic: Determining intermolecular forces
Replies: 4
Views: 67

Re: Determining intermolecular forces

Everything has dispersion forces. Nonpolar molecules can only have london dispersion intermolecular forces. Polar molecules also have dipole-dipole in addition to london dispersion forces. You can tell the type of intermolecular force based on the charges on the substance, either full charge, partia...
by Deepika Reddy 1A
Sun Nov 17, 2019 10:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: AXE Formula
Replies: 4
Views: 29

Re: AXE Formula

I believe that drawing a Lewis structure is the best way to determine the AXE formula and see the lone pairs.
by Deepika Reddy 1A
Sun Nov 17, 2019 10:11 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: bond angles
Replies: 8
Views: 35

Re: bond angles

It is because the lone pair has a lot of electron repulsion so it pushes the atoms around it away from it. This causes the atoms to get closer together as they are repelled by the electrons in the lone pair, causing the bond angles to get smaller.
by Deepika Reddy 1A
Sun Nov 17, 2019 3:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Distortion
Replies: 2
Views: 16

Re: Distortion

I believe distort is referring to the electron cloud surrounding molecules.
by Deepika Reddy 1A
Sun Nov 17, 2019 3:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole moments
Replies: 4
Views: 27

Re: Dipole moments

I do it by looking at which atom is more electronegative. The arrow points at whichever atom is more electronegative because it pulls on the electrons more.
by Deepika Reddy 1A
Sun Nov 17, 2019 3:05 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR shape clarification
Replies: 2
Views: 15

Re: VSEPR shape clarification

The lone pairs and bonded atoms are regions of electron density. These regions will cause repulsion with other regions, which affects the molecule geometries and bond angles, as these regions will want to be as far as possible from other regions in order to be the most stable.
by Deepika Reddy 1A
Sun Nov 10, 2019 5:34 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 dispersion
Replies: 4
Views: 23

Re: London dispersion

All molecules have LDF. They are considered the weakest because they are temporary charges that occur due to a temporary unequal balance of electrons. Therefore, since they are temporary partial charges, they are the weakest.
by Deepika Reddy 1A
Sun Nov 10, 2019 5:29 pm
Forum: Dipole Moments
Topic: Hydrogen bonding base pairs
Replies: 4
Views: 22

Re: Hydrogen bonding base pairs

Since AT is held by two hydrogen bonds, these bonds are broken more easily. GC is held by three hydrogen bonds, so it is harder to break the bond between them.
by Deepika Reddy 1A
Sat Nov 09, 2019 8:54 pm
Forum: Ionic & Covalent Bonds
Topic: Polarizability
Replies: 4
Views: 24

Re: Polarizability

If something is highly polarizable, that means that its electrons are more easily distorted. Large anions are larger atoms because extra electrons are added to the atom causing electron-electron repulsion, causing the atom to be bigger. This causes the electrons to be farther away from the positivel...
by Deepika Reddy 1A
Sat Nov 09, 2019 8:51 pm
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polar and Ionic Bond Character
Replies: 3
Views: 23

Re: Polar and Ionic Bond Character

The greater the difference in electronegativity is between the two atoms, usually greater than two, then it is an ionic bond. This is a step above a polar covalent bond, which has an electronegativity difference that is less than that of the atoms in an ionic bond.
by Deepika Reddy 1A
Sat Nov 09, 2019 8:45 pm
Forum: Dipole Moments
Topic: Interaction potential energy
Replies: 1
Views: 22

Re: Interaction potential energy

I think the interaction potential energy is always negative because whenever atoms interact, they are doing so because they want to be more stable than they are when they are alone. Therefore, energy is always released and the potential energy is negative because when atoms form a bond, they are bec...
by Deepika Reddy 1A
Tue Nov 05, 2019 8:20 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Solving with Heisenberg
Replies: 4
Views: 65

Re: Solving with Heisenber

This is because when they use the + or - , you should use the range. You do this by multiplying the value by two so that you get the range and can substitute that into the equation.
by Deepika Reddy 1A
Sun Nov 03, 2019 8:56 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Electron Transitions
Replies: 1
Views: 20

Re: Electron Transitions

This equation gives the energy of the level that the electrons are on. With it, you can calculate the energy of two different levels, and then do the final minus the initial to get the energy difference between the levels. This will give you the energy that the electron either absorbed to jump up or...
by Deepika Reddy 1A
Sun Nov 03, 2019 8:51 pm
Forum: Lewis Structures
Topic: Octet Rule
Replies: 6
Views: 40

Re: Octet Rule

The octet rule is that an atom wants to have enough covalent bonds to have a full shell of eight electrons so it is stable and resembles the configuration of a noble gas.
by Deepika Reddy 1A
Sat Nov 02, 2019 8:49 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Atoms to Moles
Replies: 6
Views: 100

Re: Atoms to Moles

Yes, to find the number of moles, you would divide the amount of atoms by Avogadro's constant.
by Deepika Reddy 1A
Sat Nov 02, 2019 8:44 pm
Forum: Resonance Structures
Topic: Delocalized electrons
Replies: 4
Views: 28

Re: Delocalized electrons

This means that the electrons aren't concentrated around just on atom. Instead, they are delocalized and they go between the different atoms in the molecule, instead of being associated with just one atom in the molecule. This makes the resonance structure more stable.
by Deepika Reddy 1A
Fri Nov 01, 2019 9:45 pm
Forum: Photoelectric Effect
Topic: important part of photoelectric effect
Replies: 5
Views: 44

Re: important part of photoelectric effect

There is a photon of light that comes in with a certain energy and hits a metal surface, causing an electron to be ejected. The kinetic energy of this electron is detected by a separate device. It is important to know how to calculate the energy of the incoming photon, the work function (the minimum...
by Deepika Reddy 1A
Sun Oct 27, 2019 4:37 pm
Forum: Resonance Structures
Topic: Compounds with Resonance
Replies: 1
Views: 25

Re: Compounds with Resonance

Compounds with resonance have delocalized electrons that are shared between all of the atoms. Therefore, these electrons occupy a greater volume of space, causing the compound to be more stable than if the electrons were localized near one atom.
by Deepika Reddy 1A
Sun Oct 27, 2019 2:26 am
Forum: Lewis Structures
Topic: Drawing the structure
Replies: 7
Views: 48

Re: Drawing the structure

I think it is still a Lewis structure because it shows electrons being shared between atoms.
by Deepika Reddy 1A
Fri Oct 25, 2019 8:19 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Electron Configurations
Replies: 5
Views: 43

Re: Electron Configurations

You always remove 4s electrons first before 3d because the 4s has electrons that are on the outer shell, so these electrons are lost first.
by Deepika Reddy 1A
Wed Oct 23, 2019 11:51 pm
Forum: Ionic & Covalent Bonds
Topic: lewis structures for diff bonds
Replies: 5
Views: 68

Re: lewis structures for diff bonds

For covalent bonds, the atoms share the electrons so there is a line drawn between them which shows that they are sharing the electrons. For ionic bonds, one atom completely loses the electrons while the other atom gains it. Therefore, for ionically bonded atoms, you do not draw any line connecting ...
by Deepika Reddy 1A
Wed Oct 23, 2019 5:27 pm
Forum: Electronegativity
Topic: Electronegativity values
Replies: 3
Views: 26

Re: Electronegativity values

If we did have to calculate electronegativity differences, we would probably be given a table with each element's electronegativity value. We would just find the difference between the values of the two atoms.
by Deepika Reddy 1A
Wed Oct 23, 2019 5:23 pm
Forum: Ionic & Covalent Bonds
Topic: d-block elements
Replies: 1
Views: 57

Re: d-block elements

The elements in the d block are the transition metals. Since they are metals, they are more likely to lose electrons and form cations. However, usually transition metals do not lose enough electrons to gain noble gas configurations.
by Deepika Reddy 1A
Sun Oct 20, 2019 11:44 pm
Forum: Properties of Light
Topic: Destructive Interference
Replies: 3
Views: 39

Re: Destructive Interference

Destructive interference has to do with the diffraction pattern which is when the peaks or troughs of waves traveling along one path interferes with the peaks and troughs of waves traveling along another path. Destructive interference is when the peaks of one wave interfere with the troughs of anoth...
by Deepika Reddy 1A
Sat Oct 19, 2019 11:03 am
Forum: Quantum Numbers and The H-Atom
Topic: Principal Quantum Number
Replies: 3
Views: 38

Re: Principal Quantum Number

The principal quantum number is the shell or energy level that an electron is located on. It is calculated by looking at which period the element is located in. We find the principal quantum number of the atoms in their ground state, so I do not think we have to worry about atom excitation affecting...
by Deepika Reddy 1A
Sat Oct 19, 2019 2:17 am
Forum: *Shrodinger Equation
Topic: Balmer and Lyman Series
Replies: 1
Views: 25

Re: Balmer and Lyman Series

I think it was experimentally found that the lowest level of the Balmer series is n=2 and the lowest level of the Lyman series is n=1. This just means that if the electron drops to that level then it is in that series. In calculations, it is the lowest possible level that an electron can drop to if ...
by Deepika Reddy 1A
Fri Oct 18, 2019 9:29 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Spin Magnetic Quantum #
Replies: 6
Views: 87

Re: Spin Magnetic Quantum #

The spin quantum number is just used to differentiate between the two electrons in an orbital and it is needed to completely describe an electron state. One of the electrons in an orbital is facing up and the other is facing down. The spin quantum number just tells us which is which and makes it so ...
by Deepika Reddy 1A
Fri Oct 18, 2019 9:20 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: quantum number n, l, m
Replies: 13
Views: 87

Re: quantum number n, l, m

n represents the principal quantum number which is the shell that the electron is located on. l is the angular momentum quantum number and it describes the shape of the orbital. It can either be an s orbital, p orbital, d orbital, or f orbital. m is the magnetic quantum number and it tells you the o...
by Deepika Reddy 1A
Wed Oct 16, 2019 7:08 pm
Forum: Quantum Numbers and The H-Atom
Topic: 1D.23 Homework Question
Replies: 1
Views: 21

Re: 1D.23 Homework Question

For a, n=2 tells you that we are looking at the second shell. And then l = 1 means that we are looking at a p orbital. However, the magnetic quantum number is not specified so we do not know which orientation of the p orbital it is. This means that it could be any of the three p orbitals. Therefore,...
by Deepika Reddy 1A
Sun Oct 13, 2019 9:24 pm
Forum: Properties of Electrons
Topic: Decrease in Quantum level
Replies: 3
Views: 17

Re: Decrease in Quantum level

The farther the electrons drop, the more energy they are emitting. So the farther they drop, the more energy they emit, therefore, the more energy they lose.
by Deepika Reddy 1A
Thu Oct 10, 2019 10:16 pm
Forum: Empirical & Molecular Formulas
Topic: Mass Percentage Question
Replies: 9
Views: 204

Re: Mass Percentage Question

You would use the molar mass. So find the molar mass of the entire compound, and then the molar mass of all the atoms of each element in the compound. Then divide the molar masses of all the atoms of each element by the total molar mass to get each element's mass percentage composition.
by Deepika Reddy 1A
Thu Oct 10, 2019 10:02 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Unit for Avogadro's Number
Replies: 10
Views: 129

Re: Unit for Avogadro's Number

It depends on what the question is asking for. For example, if it asks for the number of atoms in one mole of the substance, then avogadro's number would mean that there are 6.022 * 10^23 atoms of that element in that substance. Or if the questions asks how many formula units or molecules there are ...
by Deepika Reddy 1A
Thu Oct 10, 2019 9:57 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Decreasing gap between energy level
Replies: 6
Views: 67

Re: Decreasing gap between energy level

The energy that the electrons needed to emit and absorb to jump to another level was lower, so the gap became smaller. For example, the energy that is needed to be absorbed to get from n=1 to n=2 is more than the energy that needs to be absorbed when going from n=2 to n=3. Therefore, the gap between...
by Deepika Reddy 1A
Thu Oct 10, 2019 8:06 am
Forum: Properties of Electrons
Topic: Atomic Spectra and Energy Levels
Replies: 5
Views: 42

Re: Atomic Spectra and Energy Levels

Each element has its own unique emission spectrum. Each time the electrons in an atom absorb or emit light, it has to gain or lose an exact amount of energy to be able to jump up or down, and each jump has a specific wavelength of light. The emissions spectrum is made up of all the different jumps t...
by Deepika Reddy 1A
Wed Oct 09, 2019 11:48 pm
Forum: Limiting Reactant Calculations
Topic: Determining an empirical formula by combustion analysis
Replies: 2
Views: 63

Re: Determining an empirical formula by combustion analysis

You have to use the mass percentage composition of hydrogen, oxygen, and carbon. So you already found the mass of hydrogen, carbon, and oxygen. Now, just divide those by the overall mass of sucrose which is 0.528 to get the mass percentage composition of each. Then you can use that to find the empir...
by Deepika Reddy 1A
Wed Oct 09, 2019 10:06 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Homework Problem A11
Replies: 4
Views: 48

Re: Homework Problem A11

I believe the Lyman series is the ultraviolet one, which is the part of the electromagnetic spectrum with the highest energy/frequency. Since n=1 has the farthest gap from the other levels, an electron requires a lot more energy to jump up or has to emit a lot more energy to drop down, so it corresp...
by Deepika Reddy 1A
Wed Oct 02, 2019 6:27 pm
Forum: Limiting Reactant Calculations
Topic: Limiting reactant
Replies: 4
Views: 17

Re: Limiting reactant

It depends on the ratio of the moles in the balanced equation. You have to compare the moles you calculated with the ratio of moles in the balanced equation because the balanced equation tells you how many moles of one reactant is needed to react with the other reactant. So, the limiting reactant do...
by Deepika Reddy 1A
Wed Oct 02, 2019 6:23 pm
Forum: Significant Figures
Topic: Powers of 10
Replies: 10
Views: 95

Re: Powers of 10

It depends on the answer you get. if there are a lot of decimal places or zeros after the answer, then it should be in scientific notation. When you use a calculator, it'll put the number in scientific notation if it's a really big or small number.
by Deepika Reddy 1A
Wed Oct 02, 2019 11:35 am
Forum: Balancing Chemical Reactions
Topic: Stoichiometric Coefficients [ENDORSED]
Replies: 8
Views: 85

Re: Stoichiometric Coefficients [ENDORSED]

Yes, you would be able to divide (you can look at it as multiplying by 1/2, too). But you would have to make sure that all the stoichiometric coefficients in the equation can be divided by the same number and still be a whole number. If you are able to divide all the coefficients by the same number ...
by Deepika Reddy 1A
Wed Oct 02, 2019 11:30 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Frequency doesn't match energy difference
Replies: 2
Views: 76

Re: Frequency doesn't match energy difference

I am not sure I understand the question but in order for electrons to either jump up to another level or to fall back down, it needs to absorb or emit a specific amount of energy. If it doesn't have that specific amount of energy or doesn't lose that amount, it can not go to that energy level. I thi...
by Deepika Reddy 1A
Tue Oct 01, 2019 3:54 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: G.25 Dilution
Replies: 4
Views: 55

Re: G.25 Dilution

Hi,
When you dilute a solution, the number of moles will not change, so the molecules will be the same before and after you dilute because the moles are the same.

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