Search found 108 matches
- Sun Mar 14, 2021 3:07 pm
- Forum: Ideal Gases
- Topic: Reversing Reactions
- Replies: 68
- Views: 2167
Re: Reversing Reactions
When you reverse a reaction, K becomes 1/K.
- Sun Mar 14, 2021 3:06 pm
- Forum: Ideal Gases
- Topic: K and Q
- Replies: 57
- Views: 2997
Re: K and Q
While Q can be calculated at any point in the reaction, K can only be calculated when the reaction is at equilibrium.
- Sun Mar 14, 2021 3:05 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Assumption on type of system
- Replies: 13
- Views: 594
Re: Assumption on type of system
Yes! In most of our problems, we usually assume that the system is closed unless the problem states otherwise.
- Sun Mar 14, 2021 3:04 pm
- Forum: Balancing Redox Reactions
- Topic: Tips for balancing a reaction with acidic/basic condition
- Replies: 12
- Views: 718
Re: Tips for balancing a reaction with acidic/basic condition
One good tip of balancing in basic conditions is to balance the half-reactions as if you were in acidic conditions. Then, with the overall reaction, if you have any H+ left, you would change it to the same amount of H2O and add the same amount of OH- to the other side.
- Sun Mar 14, 2021 3:02 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Basic vs. Acidic Reactions
- Replies: 3
- Views: 265
Re: Balancing Basic vs. Acidic Reactions
For balancing basic reactions, Andrew Salmon showed us a technique in his office hours that may help! He said that you can balance the reaction as if it were in acidic conditions, then any H+ left in the final overall equation you would change to the same amount of H2O and add the same amount of OH-...
- Fri Mar 05, 2021 10:09 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Adding Pt(s)
- Replies: 12
- Views: 610
Re: Adding Pt(s)
Pt(s) is one example of an inert metal that can be used. In most of the examples I have noticed, Pt(s) is added to the side of the cell diagrams that do not have a conducting solid as an electrode.
- Fri Mar 05, 2021 10:00 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Redox
- Replies: 16
- Views: 779
Re: Balancing Redox
First, you want to balance the elements in the equation (ex. using H2O or OH-) and then from there you would look at the overall charge of each side. Whichever side has the more positive overall charge, you would add electrons to it to equal the opposite side.
- Fri Mar 05, 2021 9:49 pm
- Forum: Balancing Redox Reactions
- Topic: Balancing Charges
- Replies: 6
- Views: 436
Re: Balancing Charges
Q listed out some great examples of common rules to remember regarding oxidation numbers. The ones I have noticed most used are that the oxidation numbers of Oxygen is -2 and Hydrogen is +1.
- Fri Mar 05, 2021 9:47 pm
- Forum: Balancing Redox Reactions
- Topic: How to Determine if a Reaction is in Basic or Acidic Solution?
- Replies: 53
- Views: 2765
Re: How to Determine if a Reaction is in Basic or Acidic Solution?
The problem will most likely specify whether it solution is acidic or basic.
- Fri Mar 05, 2021 9:46 pm
- Forum: Balancing Redox Reactions
- Topic: states of matter
- Replies: 58
- Views: 2065
Re: states of matter
Yes! There were some problems on Sapling that did not specify whether they wanted states of matter in the final answer or not but in the end, if it was not included, the answer would be incorrect, so I would be careful with those.
- Sat Feb 27, 2021 1:25 am
- Forum: Balancing Redox Reactions
- Topic: Oxidation Numbers
- Replies: 30
- Views: 1154
Re: Oxidation Numbers
You don't need to memorize the oxidation numbers because there are simply so many, but like what was mentioned above, you should be familiar with common oxidation numbers such as that Oxygen is usually -2 and Hydrogen is usually +1. Since compounds usually include these elements, you can figure out ...
- Sat Feb 27, 2021 1:21 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Reversing Half Reactions
- Replies: 4
- Views: 210
Re: Reversing Half Reactions
I like to look at the E° values that are given because they give you an idea of which equation you want to flip. Since you want to make sure you get a positive E° value, you would flip the reaction that would produce this result. If not, you can just use the formula E°cell = E°(cathode) - E°(anode) ...
- Sat Feb 27, 2021 1:19 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Writing out Cell Diagrams
- Replies: 5
- Views: 319
Re: Writing out Cell Diagrams
If there are no solids present in the reaction (for both the cathode and anode), then you would add an inert metal which would be Pt(s). In the example you listed, I believe Hg is a solid, so it can act as the metal for the anode while the cathode does not contain a solid which is why Pt(s) is added.
- Sat Feb 27, 2021 1:17 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt Bridges
- Replies: 41
- Views: 2788
Re: Salt Bridges
Salt bridges are used the diffuse the build up of negative charge, basically offsetting the change in potential.
- Sat Feb 27, 2021 1:15 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Moles in ΔG = -nFE
- Replies: 45
- Views: 3547
Re: Moles in ΔG = -nFE
In this equation, n specifically represents the number of moles of electrons. Therefore, I like to simply balance out the half-reactions first and then compute the LCM of electrons which would be considered your "moles of electrons."
- Sat Feb 27, 2021 1:13 am
- Forum: Balancing Redox Reactions
- Topic: Acidic vs. Basic
- Replies: 20
- Views: 704
Re: Acidic vs. Basic
For acidic solutions, you would balance out the equation using H2O and then add the respective amount of H+ ions to the other side of the equation. For basic solutions, you would add H2O, add the same amount of H2O to the other side based on the amount of hydrogens in the H2O (for example, if you ad...
- Sat Feb 20, 2021 12:46 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Is thermal mugs an example of an isolated system?
- Replies: 38
- Views: 1832
Re: Is thermal mugs an example of an isolated system?
Yes, in the context of this class, we usually refer to thermals as isolated systems as long as they are closed/sealed on top.
- Sat Feb 20, 2021 12:44 pm
- Forum: Van't Hoff Equation
- Topic: Celcius vs Kelvin for T1 and T2
- Replies: 84
- Views: 6271
Re: Celcius vs Kelvin for T1 and T2
Since the formula does not indicate a change in temperature, you cannot interchange Celsius and Kelvin. Therefore, you would have to only use Kelvins in this case because the units cancel out with the gas constant, R.
- Sat Feb 20, 2021 12:27 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Open vs closed
- Replies: 31
- Views: 2650
Re: Open vs closed
Here are some definitions that clarify the difference between the different systems: Open system: Matter and energy can be exchanged with the surroundings (ex. beaker of water) Closed system: Has a fixed amount of matter but energy can exchange with the surroundings (ex. sealed beaker of water) Isol...
- Sat Feb 20, 2021 12:24 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Specific Heat
- Replies: 9
- Views: 536
Re: Specific Heat
Specific heat takes into account the mass of the compound while heat capacity does not. In more formal terms, heat capacity (typically denoted by C) is the heat required to raise the temperature of an object by 1 degree Celsius; since the heat required depends on the amount of substance, heat capaci...
- Sat Feb 20, 2021 12:20 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: q and w for an Isolated System
- Replies: 19
- Views: 3190
Re: q and w for an Isolated System
Yes, since an isolated system has no transfer of energy or mass, there will be no work or heat (w=0) and (q=0).
- Sat Feb 13, 2021 3:15 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Bomb Calorimeter
- Replies: 17
- Views: 692
Re: Bomb Calorimeter
Yes! In the context of this class, I would assume that all bomb calorimeters are isolated systems.
- Sat Feb 13, 2021 3:13 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: 4c.3
- Replies: 4
- Views: 172
Re: 4c.3
For constant volume, you would use Cv = 3/2R while for constant pressure, you would use Cp=5/2R. This applies to monatomic gases.
- Sat Feb 13, 2021 3:12 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: R Constant
- Replies: 91
- Views: 4972
Re: R Constant
It depends on the units you are given so you would have to see what information is given and what you need to solve for.
- Sat Feb 13, 2021 3:09 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: HW 4A.7
- Replies: 4
- Views: 188
Re: HW 4A.7
For Part B, you would find the heat used the raise the temperature of the water, divide it the total amount of heat from the copper kettle and water, and multiply it by 100% to find the percentage.
- Sat Feb 13, 2021 3:07 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Assumption on type of system
- Replies: 13
- Views: 594
Re: Assumption on type of system
Most of the problems I've encounter deal with a closed system, so I would assume so.
- Wed Feb 03, 2021 10:06 pm
- Forum: Ideal Gases
- Topic: Kc vs. Kp
- Replies: 71
- Views: 2192
Re: Kc vs. Kp
Yes, they are solved the same way in which it is products over reactants! There is a formula that others have listed above if you want to convert from Kc to Kp or vice versa, but I like to look at the units provided to determine which one we should be solving for.
- Wed Feb 03, 2021 10:04 pm
- Forum: Ideal Gases
- Topic: response to change in equilibria
- Replies: 6
- Views: 290
Re: response to change in equilibria
When pressure is increased, volume decreases and concentration increases. Keep in mind that the response to this change only applies to gases. Therefore, the reaction will shift to the side with less moles.
- Wed Feb 03, 2021 10:02 pm
- Forum: Ideal Gases
- Topic: Bars to atm [ENDORSED]
- Replies: 41
- Views: 1625
Re: Bars to atm [ENDORSED]
The difference between bars and atm is very small, so in this class, Dr. Lavelle said that 1 atm is equal to 1 bar. You probably don't need to worry about the difference between the values.
- Wed Feb 03, 2021 10:01 pm
- Forum: Ideal Gases
- Topic: Exo vs Endothermic
- Replies: 40
- Views: 2174
Re: Exo vs Endothermic
When I am given an equation, I like to see if bonds are being broken or formed. For example, if a compound is forming, I think of the bonds forming, so it would release heat and be exothermic. This logic can also be applied vice versa.
- Wed Feb 03, 2021 9:59 pm
- Forum: Ideal Gases
- Topic: Units for K
- Replies: 29
- Views: 1053
Re: Units for K
In the end, the units cancel out with the ratio which is why K is considered unitless.
- Wed Feb 03, 2021 9:59 pm
- Forum: Ideal Gases
- Topic: Chem BL
- Replies: 107
- Views: 6982
Re: Chem BL
I plan to take Chem 14BL when I take Chem 14C because I heard that you use a lot of material from Chem 14B for the labs, so I want to learn it all beforehand!
- Sun Jan 31, 2021 7:11 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: How Does Temperature Affect the Equilibrium Constant?
- Replies: 25
- Views: 21140
Re: How Does Temperature Affect the Equilibrium Constant?
It depends if the reaction is endothermic or exothermic. If the reaction is endothermic, an increase in temperature favors the products. If the reaction is exothermic, an increase in temperature favors the reactants.
- Sun Jan 31, 2021 7:07 pm
- Forum: Ideal Gases
- Topic: Reversing Reactions
- Replies: 68
- Views: 2167
Re: Reversing Reactions
When you reverse a reaction, the proportions of K are flipped which is why you take the inverse of K (1/K).
- Sun Jan 31, 2021 7:06 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Inert gas
- Replies: 25
- Views: 1461
Re: Inert gas
Inert gases increase the pressure of the overall reaction but do not affect the volume which is why it does not affect the concentrations of the reaction. In addition, inert gases refer to noble gases which are exceptionally stable and do not react.
- Sun Jan 31, 2021 7:04 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: K vs. Kc
- Replies: 36
- Views: 1183
Re: K vs. Kc
The book likes to use K in reference to Kp (equilibrium constant for pressure) while Kc is used for the equilibrium constant for concentrations.
- Sun Jan 31, 2021 7:03 pm
- Forum: Phase Changes & Related Calculations
- Topic: midterm respondus
- Replies: 19
- Views: 726
Re: midterm respondus
You need to download the application, and it should be automatically set up for you!
- Sun Jan 31, 2021 7:02 pm
- Forum: Phase Changes & Related Calculations
- Topic: when to assume x is insignificant
- Replies: 86
- Views: 6271
Re: when to assume x is insignificant
The rule of thumb I like to use is if the K value is less than 10<-3 (meaning the values are typically 10^-4), we can assume that the approximation rule will be okay to use. However, for acids and bases, I like to check the percentage ionization/protonation to see if it holds to the 5% rule.
- Sun Jan 31, 2021 6:58 pm
- Forum: Phase Changes & Related Calculations
- Topic: endothermic/exothermic
- Replies: 43
- Views: 4196
Re: endothermic/exothermic
Any reaction that requires the breaking of bonds is endothermic (heat is required in the reaction to break those bonds) while any reaction that requires the formation of bonds is exothermic (heat is released in the reaction). Therefore, for example, going from a gas to liquid forms bonds (exothermic...
- Sat Jan 23, 2021 10:57 pm
- Forum: Ideal Gases
- Topic: Inverse Kc [ENDORSED]
- Replies: 41
- Views: 1841
Re: Inverse Kc [ENDORSED]
If you flip an equation, you need to take the inverse of the K value.
- Sat Jan 23, 2021 10:56 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Acids and Bases
- Replies: 8
- Views: 325
Re: Acids and Bases
Yes! For this course, we are focused on the Bronsted-Lowry aspect of acids and bases where acids donate a proton and bases accept a proton.
- Sat Jan 23, 2021 10:53 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: How to fill in 2nd row of ICE table?
- Replies: 25
- Views: 699
Re: How to fill in 2nd row of ICE table?
It depends on what you are given. If you are given simply the initial concentration of reactants, you can assume that the reactants will become products. However, if you are given the initial concentration of both the reactants and products, you have to determine the value for Q to see if it is grea...
- Sat Jan 23, 2021 10:51 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Deprotonation Percentage Formula
- Replies: 6
- Views: 190
Re: Deprotonation Percentage Formula
It is the same as the percentage protonation formula but for acids which is [concentration of A- after equilibrium]/[initial concentration of HA] x 100%.
- Sat Jan 23, 2021 10:46 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Tables
- Replies: 36
- Views: 1518
Re: ICE Tables
The stoichiometric coefficients determine the value of C in the ICE table.
- Fri Jan 15, 2021 1:49 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Simplifying Expressions: K<10^?
- Replies: 6
- Views: 148
Re: Simplifying Expressions: K<10^?
The standard rule typically is less than 10^-3, but Lavelle did mention that it is safe to use numbers that are multiplied by 10^-4 because some numbers may be multiplied to 10^-3 but are not small enough. Therefore, you want a number that is “less than” 10^-3.
- Fri Jan 15, 2021 1:17 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: textbook 5.35
- Replies: 3
- Views: 157
Re: textbook 5.35
When we calculate Kp, we want to make sure our units for the partial pressures are converted to either bar or atm. In this case, they divided by 100 to convert the units.
- Fri Jan 15, 2021 1:15 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: lecture 5 question
- Replies: 13
- Views: 472
Re: lecture 5 question
Yes! Memorizing them really helps. I would memorize the strong acids and know that strong bases are usually Group 1/2 elements with an oxide (—O) or hydroxide (—OH) attached.
- Fri Jan 15, 2021 1:12 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Pressure vs. concentration
- Replies: 9
- Views: 186
Re: Pressure vs. concentration
Usually, I like to refer to the units/reaction that is given. To calculate Kp, the units would usually be given in either bar or atm. On the other hand, to calculate Kc, the units would usually be given as M (mol/L).
- Fri Jan 15, 2021 1:08 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Tables
- Replies: 12
- Views: 279
Re: ICE Tables
to add on to this, how do you know when to put 0 for the intital concentration of the product versus a concentration that is given? I thought i t was always 0 since the reaction doesn't occur yet but sometimes you put in a concentration... Typically, the problem states whether or not a reaction is ...
- Fri Jan 15, 2021 1:04 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Tables
- Replies: 12
- Views: 279
Re: ICE Tables
It all depends on what the initial concentrations are. If the problem gives just initial [reactant] and no product, you know the reactants are going to be subtracted so it would be -x or -2x or whatever matches to stoich coefficient. However, if you are given both initial [reactant] and [product] y...
- Sat Jan 09, 2021 12:53 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Calculating Equilibrium Concentrations with Quadratic & Cubic Equations
- Replies: 5
- Views: 217
Re: Calculating Equilibrium Concentrations with Quadratic & Cubic Equations
Lavelle mentioned in one of the Audio Visual lectures that the rule applies to both cubic and quadratic equations when one student asked. In addition, some of the textbook answers mentioned the rule applying to quadratic equations as well.
- Sat Jan 09, 2021 12:48 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Q and K
- Replies: 17
- Views: 684
Re: Q and K
K only changes when the temperature changes. In this case, you would have different values for Q in which after time, these values should equal K.
- Sat Jan 09, 2021 12:46 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Calculating Q
- Replies: 7
- Views: 242
Calculating Q
On Problem #11 (part a) in Section 5G of the textbook, they gave the following equation: 2BCl3 (g) + 2Hg (l) --> B2Cl4 (s) + Hg2Cl2 (s) and asked us to find Q. In this case, the answer was in partial pressure form rather than in concentration form. I was a little confused by this because I thought a...
- Sat Jan 09, 2021 12:40 am
- Forum: Ideal Gases
- Topic: Kc vs Kp
- Replies: 109
- Views: 4273
Re: Kc vs Kp
Like others have said above, it depends on the problem given. Sometimes, an equation would only contain gases, yet they would calculate Kc. Typically, the problem would hint whether they want you to solve for Kc or Kp based on the units given.
- Sat Jan 09, 2021 12:35 am
- Forum: Ideal Gases
- Topic: Gas constant R
- Replies: 26
- Views: 1024
Re: Gas constant R
There are varying values for the constant R based on which unit you choose for partial pressure. However, since we calculate partial pressure in bar or atm most of the time, you would either use 8.20574x10^-2 (for atm) or 8.31446x10^-2 (for bar).
- Tue Dec 15, 2020 10:09 pm
- Forum: Electronegativity
- Topic: Periodic Table Trend
- Replies: 40
- Views: 2109
Re: Periodic Table Trend
Electronegativity and ionization energy both have trends that increase as you move towards the right corner of the periodic table (towards Fluorine).
- Tue Dec 15, 2020 10:07 pm
- Forum: Coordinate Covalent Bonds
- Topic: Polydentate Ligands
- Replies: 8
- Views: 389
Re: Polydentate Ligands
My two criteria include number of lone pairs (which I often noticed on Nitrogen atoms in the molecules we analyzed) and if spacer atoms (Carbon atoms) are present which allow the molecule to distort itself around the transition metal.
- Tue Dec 15, 2020 10:04 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Radicals
- Replies: 3
- Views: 133
Re: Radicals
When I attended a UA session, he told me that you put the extra electron on the LEAST electronegative atom. However, it makes more sense to place it on the atom that reduces formal charge so it can become as close to zero as possible.
- Tue Dec 15, 2020 10:01 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma and Pi Bonds
- Replies: 24
- Views: 991
Re: Sigma and Pi Bonds
Like some students have said above, I don’t believe a double bond is solely considered a pi-bond because it contains one sigma and one pi bond. You just have to know that a double bond consists of one sigma and one pi bond.
- Tue Dec 15, 2020 9:58 pm
- Forum: Conjugate Acids & Bases
- Topic: conjugate acids and bases
- Replies: 8
- Views: 376
Re: conjugate acids and bases
Something I like to remember is that to form a conjugate acid, you add an H+ and add one to the charge of the molecule while to form a conjugate base, you subtract an H+ and subtract one from the overall charge of the molecule.
Re: Sapling 1
When naming compounds, you do not consider the prefixes. Therefore, you would only look at ammine and chloro when alphabetizing the name.
- Sun Dec 06, 2020 5:21 pm
- Forum: Naming
- Topic: Sapling Q1
- Replies: 20
- Views: 857
Re: Sapling Q1
In this problem, cobalt has an oxidation number of +3 instead of +2. Therefore, the roman numeral next to cobalt should be (III) not (II) because NH3 is neutral and Cl has a -1 charge. Therefore, you want the coordination sphere to have a charge of +1 to cancel out the charge of the outside Cl which...
- Sun Dec 06, 2020 5:17 pm
- Forum: Naming
- Topic: Prefixes for parts outside of Coordination Compound
- Replies: 7
- Views: 326
Re: Prefixes for parts outside of Coordination Compound
I believe you only add prefixes to ligands which form a coordinate covalent bond with the transition metal (those inside the coordination sphere). Therefore, anything outside of the brackets do not have prefixes.
- Sun Dec 06, 2020 5:14 pm
- Forum: Naming
- Topic: Order of Ligands/naming
- Replies: 28
- Views: 1073
Re: Order of Ligands/naming
You would arrange the ligands in alphabetical order. When arranging the ligands in alphabetical order, you do not consider the prefix.
- Sun Dec 06, 2020 5:12 pm
- Forum: Naming
- Topic: Naming Coordination Compounds
- Replies: 9
- Views: 503
Re: Naming Coordination Compounds
If the complex has an overall negative charge, -ate is added to the stem of the transition metal's name.
- Wed Nov 25, 2020 8:50 pm
- Forum: Hybridization
- Topic: Long Pairs/Double & Triple Bonds
- Replies: 9
- Views: 468
Re: Long Pairs/Double & Triple Bonds
Since hybridization only takes into account the regions of electron densities around a particular atom, double bonds and triple bonds still count as one region of electron density. In addition, lone pairs count as one region of electron density.
- Wed Nov 25, 2020 2:08 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: axial vs. equatorial
- Replies: 5
- Views: 261
Re: axial vs. equatorial
When lone pairs occupy equatorial positions, it only repels two axial bonds at 90º, whereas if the lone pair occupied the axial position it would interact with 3 equational bond's. Therefore, lowest energy is achieved when lone pairs are in equatorial position because there is less repulsion. I sec...
- Wed Nov 25, 2020 2:03 pm
- Forum: Hybridization
- Topic: Hybridization Clarification
- Replies: 9
- Views: 498
Re: Hybridization Clarification
I like to refer back to the name "hybridization" when I think about what it means! The word "hybrid" is in its name which tells me that we are combining something. In this case, we are combining atomic orbitals to become hybrid orbitals that can hold the correct number of electro...
- Wed Nov 25, 2020 1:59 pm
- Forum: Student Social/Study Group
- Topic: How have your study habits changed?
- Replies: 45
- Views: 1645
Re: How have your study habits changed?
I have definitely seen my studying habits shift dramatically since starting college. I like to progressively study by starting about a week or two weeks before the exam. Then, each day, I review content chronologically, and about a week before the exam, I like to test myself by redoing UA worksheets...
- Wed Nov 25, 2020 1:55 pm
- Forum: Student Social/Study Group
- Topic: Big Sad: Midterm 2
- Replies: 86
- Views: 5343
Re: Big Sad: Midterm 2
Eunice_Castro_1G wrote:BoparaiAdeshsurjit2I wrote:Does anybody know the grading scheme. If 50% is needed to pass how much do you need to get an A?
Hello! So there are a total of 500 points and to get an A you can only miss 5 points. Hope this helps!
I believe you can only miss 35 points in total to receive an A (93%) in the class!
- Sun Nov 22, 2020 1:21 pm
- Forum: Electronegativity
- Topic: Polarizability vs. Polarizing Power
- Replies: 6
- Views: 361
Re: Polarizability vs. Polarizing Power
Polarizability increases as atoms are able to be distorted more. Therefore, it practically measures how distorted an atom can be (typically applies to anions). If an atom is highly polarizable, it can be easily distorted. I believe polarizability follows the same trend for atomic radius because the ...
- Sun Nov 22, 2020 1:15 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: The most plausible structure
- Replies: 4
- Views: 153
Re: The most plausible structure
The criteria I usually try to meet when looking for the most plausible structure include: Which structure has the most atoms with formal charges closest to 0? Are the negative formal charges on the most electronegative atoms? If the structure satisfies these two requirements, I like to consider it t...
- Sun Nov 22, 2020 1:13 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Best Formal Charge Equations
- Replies: 24
- Views: 990
Re: Best Formal Charge Equations
The simplest way I have come up with calculating formal charge is with the following equation: Formal charge = # of valence electrons - (# of "things" around the atom) These things correlate to lines/dots. Therefore, I simply count up how many lines and dots there are around the atom and s...
- Sun Nov 22, 2020 1:11 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Tips for memorizing different molecular shapes
- Replies: 9
- Views: 2159
Re: Tips for memorizing different molecular shapes
Lavelle stated in his lecture that molecules with the same AXE notation will typically have the same shape. Therefore, that could help with the memorization process of the shapes. Other than that, it would also be helpful to actually picture what the molecule would look like in 3D. However, this may...
- Sun Nov 22, 2020 1:08 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Remembering Molecular Shapes
- Replies: 4
- Views: 225
Re: Remembering Molecular Shapes
I recall that Lavelle stated in his lecture that molecules with the same AXE notation will typically have the same shape. Therefore, that could help with the memorization process of the shapes. Other than that, it would also be helpful to actually picture what the molecule would look like in 3D.
- Sun Nov 15, 2020 7:42 pm
- Forum: Octet Exceptions
- Topic: Radicals
- Replies: 7
- Views: 266
Re: Radicals
I think those are the two fundamentals that are necessary to know when it comes to radicals: the molecules have an uneven amount of valence electrons (odd number) and radicals are highly reactive.
- Sun Nov 15, 2020 7:37 pm
- Forum: Resonance Structures
- Topic: Resonance Structures Clarification
- Replies: 8
- Views: 319
Re: Resonance Structures Clarification
I believe you would have to look at formal charge to determine the most favorable structure first (least energy) and then from there, you can determine the resonance structures.
- Sun Nov 15, 2020 7:35 pm
- Forum: Resonance Structures
- Topic: Sapling Resonance Structures
- Replies: 4
- Views: 330
Sapling Resonance Structures
When I was doing Sapling, I noticed that they included the "non-favorable" structure in the answer when they were explaining the resonance hybrid. I thought we first look for the most favorable structure and then if there is resonance, that is part of the resonance hybrid?
- Sun Nov 15, 2020 7:33 pm
- Forum: Lewis Structures
- Topic: VSEPR
- Replies: 4
- Views: 131
Re: VSEPR
I don't think we will be tested on VESPR but predicting the geometry of the molecules will definitely help when drawing the Lewis structures.
- Sun Nov 15, 2020 7:24 pm
- Forum: Lewis Structures
- Topic: Confusions with Expanded Octets in Period 3
- Replies: 2
- Views: 130
Confusions with Expanded Octets in Period 3
I am a bit confused about the idea of expanded octets. In the book, it states that only p-block atoms in period 3 or later can expand their valence shells due to the empty d-orbitals. I understand this for p-block atoms after period 4 due to the 3d electrons and etc. However, how come the p-block at...
- Sat Nov 07, 2020 12:55 am
- Forum: Electronegativity
- Topic: Periodic Trends
- Replies: 9
- Views: 826
Periodic Trends
Are there any easy methods that could possibly help me memorize the periodic trends?
- Sat Nov 07, 2020 12:52 am
- Forum: Ionic & Covalent Bonds
- Topic: Formal Charge Equation
- Replies: 10
- Views: 430
Re: Formal Charge Equation
Since atoms form covalent bonds with each other, they are sharing electrons with each other. Therefore, each bond line can be counted as one electron because we are only taking into consideration one atom which is sharing one electron with another atom (forming the bond line).
- Sat Nov 07, 2020 12:48 am
- Forum: Resonance Structures
- Topic: Resonance Structures
- Replies: 10
- Views: 376
Re: Resonance Structures
A resonance hybrid is a structure that averages the bond lengths from all of the resonance structures, so it is basically a collective representation of a molecule.
- Sat Nov 07, 2020 12:47 am
- Forum: Resonance Structures
- Topic: resonance structures
- Replies: 8
- Views: 370
Re: resonance structures
Resonance structures are a group of Lewis structures that collective represent the same molecule but may have different bonding structures. Altogether, resonance structures can be represented by a resonance hybrid which practically averages the bond lengths.
- Sat Nov 07, 2020 12:42 am
- Forum: Lewis Structures
- Topic: lewis structure
- Replies: 17
- Views: 541
Re: lewis structure
Depending on the charge of the atom or molecule, that will determine which charge goes outside of the brackets. For example, NO3- would be [NO3]- (with the negative charge on the outside of the brackets).
- Sat Oct 31, 2020 11:34 pm
- Forum: DeBroglie Equation
- Topic: Finding the mass of a molecule
- Replies: 6
- Views: 230
Re: Finding the mass of a molecule
Anytime you see the word "diatomic," you would find the molar mass of two molecules. In this case, it is two Hydrogen molecules (H2). Then, you can use this value in your conversion!
- Sat Oct 31, 2020 11:32 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: General Heisenberg Question
- Replies: 7
- Views: 308
Re: General Heisenberg Question
When dealing with percentages in uncertainty, you would have to take that percentage amount of the value given (not just take the percentage as the uncertainty value). Therefore, you would take 2% of 5.00 for the example you gave which will give you your uncertainty value.
- Sat Oct 31, 2020 11:27 pm
- Forum: Properties of Light
- Topic: Is c always the speed of light?
- Replies: 92
- Views: 4740
Re: Is c always the speed of light?
Yes, so far in this class, we have only learned that c is equal to the speed of light (3.00x10^8 m/s).
- Sat Oct 31, 2020 11:26 pm
- Forum: Properties of Light
- Topic: How to remember what v is in equations
- Replies: 46
- Views: 6840
Re: How to remember what v is in equations
In most cases, velocity deals with a matter that has mass (electrons, neutrons, etc.) whereas frequency deals with wave-like properties, typically found in light. In addition, it is important to keep in mind the conceptual idea behind each equation which will help you understand which equations cont...
- Sat Oct 31, 2020 11:24 pm
- Forum: Properties of Light
- Topic: Relationship between wavelength and frequency
- Replies: 10
- Views: 3376
Re: Relationship between wavelength and frequency
Wavelength and frequency are inversely related to each other because multiplying wavelength and frequency equals to a constant (the speed of light). Therefore, they will always multiply to 3.00x10^8. The higher the frequency, the shorter the wavelength. Likewise, the lower the frequency, the longer ...
- Sun Oct 25, 2020 2:05 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Confusion with Uncertainty Values
- Replies: 7
- Views: 168
Re: Confusion with Uncertainty Values
Uncertainty is mainly about the range of values that the real value could be in. The actual value of the velocity doesn't really matter. For the question you specified, the uncertainty in velocity would be 4 m/s. Thank you for the clarification! I have a better understanding of it now. Do you know ...
- Sat Oct 24, 2020 6:13 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: When do we use Heisenberg indeterminacy equation
- Replies: 10
- Views: 269
Re: When do we use Heisenberg indeterminacy equation
Something you should keep in mind with Heisenberg's Indeterminacy Equation is that the smaller the mass of an object, the more "unknown" or "uncertain" the object's position will be. If we know everything about where a particle is located (the uncertainty of position is small), w...
- Sat Oct 24, 2020 6:08 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Confusion with Uncertainty Values
- Replies: 7
- Views: 168
Confusion with Uncertainty Values
I'm a little confused on the idea of uncertainty. For example, if the problem tells us that the velocity is 14.3 with an uncertainty of +/- 2, would our velocity value just be 4, or would it be 14.3+4?
- Sat Oct 24, 2020 6:07 pm
- Forum: Properties of Light
- Topic: Wavelength
- Replies: 14
- Views: 511
Re: Wavelength
My TA said that it doesn't matter, but wavelength is usually in units of nanometers. However, since the midterm is multiple choice, this may not be too big of an issue that you have to worry about. Just make sure your value is correct when you convert units!
- Sat Oct 24, 2020 6:04 pm
- Forum: Properties of Light
- Topic: Constants
- Replies: 21
- Views: 537
Re: Constants
I like to use at least three decimal places, but the more numbers you use, the more accurate your answer will be. If you have a graphing calculator, you can also copy the exact answer and apply it into the equation you are solving for.
- Sat Oct 24, 2020 6:02 pm
- Forum: *Black Body Radiation
- Topic: Midterm
- Replies: 14
- Views: 600
Re: Midterm
Dr. Lavelle described that a black body is something that absorbs and emits all wavelengths, but this is a topic that is out of the scope of our course, so we do not need to know it for the midterm!
- Sat Oct 17, 2020 8:35 pm
- Forum: Einstein Equation
- Topic: m vs nm
- Replies: 66
- Views: 3209
Re: m vs nm
My TA said that it doesn't matter, but wavelength is typically expressed in nanometers which is why they prefer wavelength to be in units of nm!
- Sat Oct 17, 2020 8:32 pm
- Forum: Student Social/Study Group
- Topic: How do you study?
- Replies: 19
- Views: 606
Re: How do you study?
I really like doing problems multiple times to really engrain the concepts into my mind, so when I see it on exams (where questions are more difficult), I can sort of piece together how to solve certain problems.
- Sat Oct 17, 2020 8:30 pm
- Forum: Student Social/Study Group
- Topic: Need suggestions on study websites
- Replies: 4
- Views: 428
Re: Need suggestions on study websites
Like multiple students have already said above, I really like watching Khan Academy because the moderators do a great job of explaining concepts step-by-step. In addition, I like watching Crash Course because it gives me a better understanding of broader concepts such as if you don't know how certai...
- Sat Oct 17, 2020 8:26 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Step Up Sessions
- Replies: 71
- Views: 6486
Re: Step Up Sessions
Are step up sessions or workshop sessions better for understanding material that may be on exams? Can I still attend workshop sessions if I don't have a strong background in chemistry? Step-up sessions allow you to walk through simpler problems step-by-step where as workshops allow you to engage in...