Search found 104 matches
- Tue Mar 16, 2021 10:49 am
- Forum: General Rate Laws
- Topic: Increasing or decreasing the rate constant
- Replies: 3
- Views: 1727
Re: Increasing or decreasing the rate constant
A reaction without a catalyst would have a smaller rate constant for sure but with a catalyst it’s important to distinguish that this new reaction takes an entirely different path. Furthermore, yes temperature increase does increase K.
- Tue Mar 16, 2021 10:47 am
- Forum: General Rate Laws
- Topic: Intermediate
- Replies: 59
- Views: 3400
Re: Intermediate
Intermediates are molecules that appear in the initial reaction but do not end up in the final reaction. In the first few steps they become products and become cancelled out so they are not seen in the final reaction.
- Fri Mar 12, 2021 11:46 am
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Orders of reactants
- Replies: 14
- Views: 672
Re: Orders of reactants
It tells us how the reactant affects the reaction rate. Different orders have different equations that are equal to the slope which is the reaction rate.
- Fri Mar 12, 2021 11:43 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Units for Activation Energy
- Replies: 28
- Views: 1818
Re: Units for Activation Energy
Activation energy is in the units kJ/mol.
- Fri Mar 12, 2021 11:43 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Activation Energy and reaction rate
- Replies: 2
- Views: 186
Re: Activation Energy and reaction rate
Basically to activate the reaction you need lots of energy. Because energy there’s not always huge amounts of available energy the reaction is much slower hence the slower reaction rate
- Sun Mar 07, 2021 10:04 pm
- Forum: First Order Reactions
- Topic: Equation Confusion
- Replies: 16
- Views: 609
Re: Equation Confusion
The first equation you use for zero order reactions while the second is for first order reactions. I was confused on this as well!
- Sun Mar 07, 2021 10:03 pm
- Forum: General Rate Laws
- Topic: slope of rate (differential rate law)
- Replies: 5
- Views: 312
Re: slope of rate (differential rate law)
X is the time while the Y is the concentration the slope of the graph shows the Rate of the reaction. Important to realize the graph goes up and down over time because the concentration fluctuates as well.
- Sun Mar 07, 2021 9:26 pm
- Forum: General Rate Laws
- Topic: Multiple Reactants
- Replies: 7
- Views: 356
Re: Multiple Reactants
When you have multiple reactants you have to look at the reactant that has the least amount almost like looking at the limiting reactant back from foundations. The smallest one will have the largest affect on the reaction because once it runs out, the rest become pointless until a reverse reaction t...
- Sun Mar 07, 2021 8:56 pm
- Forum: General Rate Laws
- Topic: Factors Affecting k
- Replies: 83
- Views: 4448
Re: Factors Affecting k
The rate constant K can only change when temperature changes!
- Sun Mar 07, 2021 8:54 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: pH
- Replies: 17
- Views: 832
Re: pH
pH level measures the amount of hydronium ions within something or determining the strength of the acid. pOH measures the strength of a base and the amount of hydroxide present on a scale of 1-14 for both.
- Sun Feb 28, 2021 9:48 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Log or ln
- Replies: 22
- Views: 1493
Re: Log or ln
They are not interchangeable!!!! At all! Both will give you different solutions!! Make sure you use log and ln appropriately, only in one equation you use the log when you have the .059V/n in the Nernst Equation is when you use log(q) otherwise do not!
- Sun Feb 28, 2021 9:46 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n in ∆G = -nFE
- Replies: 80
- Views: 3615
Re: n in ∆G = -nFE
The n is referring the moles of electrons being transferred so when you look at a redox reaction first look at the charges from the left and the right. If the right is stable and the left is 3- then there was a transference of 3 electrons.
- Sun Feb 28, 2021 9:45 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: E vs E naught
- Replies: 36
- Views: 1437
Re: E vs E naught
E naught is in standard conditions meaning 1 atm , 298k but E is not that is why you have to find the new temperature and different pressure when you use the E equation.
- Sun Feb 28, 2021 9:42 pm
- Forum: Balancing Redox Reactions
- Topic: Standard Potentials and Reactions
- Replies: 12
- Views: 663
Re: Standard Potentials and Reactions
There will be instances where we have to solve for the Standard Potentials ourselves using the equation but if he does not want to have super long questions he will give us the stand potential to find the solution to the question using the standard potentials to find the total energy for instance.
- Sun Feb 28, 2021 9:38 pm
- Forum: Balancing Redox Reactions
- Topic: Determining which molecule is the oxidizing agent
- Replies: 49
- Views: 1721
Re: Determining which molecule is the oxidizing agent
Oxidizing agent is being reduced which allows ANOTHER element to be oxidized! Confusing but interesting how it works out.
- Sun Feb 28, 2021 9:37 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation Numbers
- Replies: 30
- Views: 1154
Re: Oxidation Numbers
You should know most oxidation numbers from fundamentals of 14A by looking at the periodic table of elements of what an element wants and how it can achieve its octet by losing or gaining electrons.
- Sun Feb 21, 2021 8:58 pm
- Forum: Calculating Work of Expansion
- Topic: Irreversible vs. Reversible
- Replies: 6
- Views: 403
Re: Irreversible vs. Reversible
The difference between irreversible and reversible reactions is that irreversible reactions happen very fast and the energy change is immediate. The reversible reactions are very slow and as heat is transferred through the reaction. It absorbs heat from the environment and this makes reversible reac...
- Sun Feb 21, 2021 8:54 pm
- Forum: Calculating Work of Expansion
- Topic: Value of Q
- Replies: 20
- Views: 818
Re: Value of Q
Q is the equilibrium constant. If you have molar concentrations of the reactants and products you can make it reactants/products and put them to the power of number of moles. That gives you the Q value.
- Sun Feb 21, 2021 8:52 pm
- Forum: Calculating Work of Expansion
- Topic: Spontaneous
- Replies: 26
- Views: 1369
Re: Spontaneous
Reactions are spontaneous only when the reaction still occurs even when there is no additional input of energy.
- Sun Feb 21, 2021 8:50 pm
- Forum: Calculating Work of Expansion
- Topic: Negative Work
- Replies: 30
- Views: 1072
Re: Negative Work
If the work is negative than that means the system is doing work. When it does work it loses or uses energy hence the reason its negative.
- Sun Feb 21, 2021 8:47 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 2nd Law
- Replies: 11
- Views: 579
Re: 2nd Law
The second law of thermodynamics states that entropy increases with spontaneity. The equation is S = qrev/t.
- Sun Feb 21, 2021 8:46 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: entropy positive value
- Replies: 30
- Views: 1678
Re: entropy positive value
Entropy values are always positive values because spontaneous values need to be constant.
- Sun Feb 14, 2021 11:13 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Determining greater molar entropy
- Replies: 5
- Views: 376
Re: Determining greater molar entropy
It’s not the size of the atoms but the size of the molecules. Larger molecules typically have a larger entropy.
- Sun Feb 14, 2021 11:11 pm
- Forum: Calculating Work of Expansion
- Topic: U, q, w
- Replies: 11
- Views: 768
Re: U, q, w
The change in U = q+w but also if the temperature is stable then U remains 0 so -q = w.
- Sun Feb 14, 2021 11:10 pm
- Forum: Calculating Work of Expansion
- Topic: Conceptual Explanation
- Replies: 3
- Views: 191
Re: Conceptual Explanation
The expansion and compression are done in such small rates back and forth that it’s infinitely small hence 0 because truly there is no real change. I think of it like chemical equilibrium. The forward and reverse reactions rates are equal the reactions don’t just stop.
- Sun Feb 14, 2021 11:08 pm
- Forum: Calculating Work of Expansion
- Topic: Work Done on System?
- Replies: 12
- Views: 497
Re: Work Done on System?
If you are pulling the piston it makes the work negative as their is volume expansion if your system is the within the piston and it’s pressure.
- Sun Feb 14, 2021 11:06 pm
- Forum: Calculating Work of Expansion
- Topic: irreversible vs reversible
- Replies: 14
- Views: 640
Re: irreversible vs reversible
Reversible reactions are slow and allow heat to come into replace the energy lost during expansion while irreversible reactions are very fast.
- Sun Feb 07, 2021 8:05 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: deltaU
- Replies: 29
- Views: 732
Re: deltaU
Delta U is just the change of energy in a system, q + w which is heat + work.
- Sun Feb 07, 2021 8:04 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Work
- Replies: 39
- Views: 1356
Re: Work
Negative work means that’s how much energy is needed, so if you have a larger negative value, it means that the reaction or whatever you’re doing needs more energy.
- Sun Feb 07, 2021 8:03 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Combustion = Exothermic
- Replies: 23
- Views: 738
Re: Combustion = Exothermic
The way to look at combustion is by looking at the products and reactants. If the products don’t have bonds, then the products combusted and released heat to break their bonds.
- Sun Feb 07, 2021 7:56 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Closed System
- Replies: 52
- Views: 2475
Re: Closed System
Closed system still can interact with surroundings just in a sealed container. So it’s like a water bottle with the cap, the amount of water cannot increase with rain but some of the water can evaporate because of the sun.
- Sun Feb 07, 2021 7:54 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Can heat capacities be negative?
- Replies: 52
- Views: 13341
Re: Can heat capacities be negative?
Heat capacities cannot be negative because it is the amount of temperature to be either gained or lost to change a temperature. So it is always a positive value.
- Sun Feb 07, 2021 7:52 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Calorimeters
- Replies: 10
- Views: 404
Re: Calorimeters
Calorimeter calculate the amount of heat given off in a reaction, these are very useful because no heat is lost to surroundings nor is heat absorbed.
- Sun Jan 31, 2021 7:17 pm
- Forum: Phase Changes & Related Calculations
- Topic: H and q
- Replies: 47
- Views: 1494
Re: H and q
Q represent heat, while H is a state function for enthalpy meaning the change in amount of heat.
- Sun Jan 31, 2021 7:16 pm
- Forum: Phase Changes & Related Calculations
- Topic: reaction shifts
- Replies: 18
- Views: 602
Re: reaction shifts
First recognize if the reaction is endothermic or exothermic. If it takes heat to make products and you add more heat, then the reaction will shift towards the products. And vice versa.
- Sun Jan 31, 2021 7:13 pm
- Forum: Phase Changes & Related Calculations
- Topic: Vapor vs gas
- Replies: 121
- Views: 8303
Re: Vapor vs gas
Vapor and Gas are the same thing, if it’s water vapor it is water in its gas phase.
- Sun Jan 31, 2021 7:11 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: delta H vs delta U
- Replies: 11
- Views: 451
Re: delta H vs delta U
Delta H is referring to only the heat exchanger while Delta U incorporates all types of energy exchanges.
- Sun Jan 31, 2021 6:26 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 58
- Views: 2723
Re: Hess's Law
Enthalpies are state functions! That’s why they can be added together in order to solve for unknown enthalpies.
- Sun Jan 24, 2021 8:17 am
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Ionization Constant of water
- Replies: 4
- Views: 192
Re: Ionization Constant of water
Very important because if you do the -log of that you will get 14 which explains why pH and pOH add up to 14 as well. We can use 1*10^-14 directly and find the kA and kB values as necessary.
- Sun Jan 24, 2021 8:15 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Acids and Bases
- Replies: 8
- Views: 319
Re: Acids and Bases
Well technically all of these acids and bases can fit any of the definitions but since we look at the proton moving from the acid or base it is a Bronsted Lowry, however it’s the same thing as Lewis acid and base because anytime a proton it is always a pair of electrons being a full shell for the Hy...
- Sun Jan 24, 2021 8:11 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Determining pH
- Replies: 18
- Views: 722
Re: Determining pH
You have to do the -log of the concentrations of OH- and H30+ to find the pH or pOH.
- Sun Jan 24, 2021 8:09 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Charge of Predominant Species
- Replies: 5
- Views: 207
Re: Charge of Predominant Species
Anytime you have the original species that’s already in solution, and for example say it’s pH is 3 and you put in another acid that is pH 4, solution is not charged because there will not be anymore hydroniums being formed because it is already more acidic than the acid being placed in. Hope this he...
- Sun Jan 24, 2021 8:06 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Week 2 Sapling Hw #2
- Replies: 8
- Views: 404
Re: Week 2 Sapling Hw #2
Do your ice table and find the concentration of Hydroniums in the solution, after that it’s easy just multiply by 1/100.
- Sun Jan 17, 2021 2:46 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Chart with Gas Pressures
- Replies: 8
- Views: 273
Re: ICE Chart with Gas Pressures
Yup exactly you want to use bar and you want to use pressures not molarity. Pressure equilibrium is different from concentration of molarity.
- Sun Jan 17, 2021 2:45 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Amphiprotic
- Replies: 8
- Views: 300
Re: Amphiprotic
Amphiprotic is anything that can act as a Base or an acid by giving always or accepting electrons. Water does this in all reactions as when it’s bonded with an strong acid it creates acid or with a strong base it creates a base.
- Sun Jan 17, 2021 2:37 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ka x Kb
- Replies: 11
- Views: 307
Re: Ka x Kb
Ka and Kb will always = 1x 10^-14 which is the kW value. The reason why is because these two values are the concentrations of hydroniums and OH, which shows the basicity or acidity of the solution. When you do the log base of these values it gives you the pH. So it has to add up to 14.
- Sun Jan 17, 2021 2:31 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Sapling Number 4
- Replies: 5
- Views: 2178
Re: Sapling Number 4
Make sure all values are correct under the square root. Some may be negative but when multiplied with the C which should be a negative value you’ll get a positive X.
- Sun Jan 17, 2021 2:28 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Ice Box Method
- Replies: 14
- Views: 403
Re: Ice Box Method
For the ice box method you have to look at the reactants and products. In most reactions you will see the reactants producing the products so the reactants will decrease. However in some cases if you’re working backwards you’ll have to subtract.
- Sun Jan 10, 2021 8:38 pm
- Forum: Ideal Gases
- Topic: Units of Temperature
- Replies: 82
- Views: 3213
Re: Units of Temperature
For the ideal gas law you want to use Kelvins because it often cancels with the R.
- Sun Jan 10, 2021 8:37 pm
- Forum: Ideal Gases
- Topic: Ideal Gas Equation units
- Replies: 4
- Views: 258
Re: Ideal Gas Equation units
P standing for pressure should be in atm, V is the volume which should be in Liters. n is the moles of what you have, r is the constant that should be in ATM or just the same as whatever your P was. Finally T meaning temperature should be in Kelvins.
- Sun Jan 10, 2021 8:36 pm
- Forum: Ideal Gases
- Topic: Kc vs Kp
- Replies: 109
- Views: 4271
Re: Kc vs Kp
Use KP when you have anything to do with pressure. If you see any given partial pressure you want to use KP while KC is for varying molarity/ amount of the product/reactants you have.
- Sun Jan 10, 2021 8:34 pm
- Forum: Ideal Gases
- Topic: Units for Pressure
- Replies: 41
- Views: 2330
Re: Units for Pressure
Professor Lavelle said to use the atm for pressure. He said that it’s not too different and he prefers atm since it’s been around longer.
- Sun Jan 10, 2021 8:34 pm
- Forum: Ideal Gases
- Topic: value of R
- Replies: 24
- Views: 907
Re: value of R
R is just the constant so you only use different R values dependent on the values that are in front of you. So if you have atm as one of the pressures you will use the R value with atm.
- Wed Dec 16, 2020 6:03 pm
- Forum: Lewis Acids & Bases
- Topic: Water
- Replies: 63
- Views: 2581
Re: Water
Water is amphoteric, it has the ability to act as an acid or base. Water acts as a base when mixed with acid and vice versa, this is a very important topic in acids in bases because often most acids/bases are mixed with water to truly understand their acidity or basicity.
- Wed Dec 16, 2020 6:01 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis vs Bronsted
- Replies: 20
- Views: 1024
Re: Lewis vs Bronsted
The important difference between lewis and Bronsted is the definition. Lewis acid/base definition is based on the accepting or donating of pairs of electrons while Bronsted is based on the accepting and donating of a proton in the form of an H+ ion.
- Wed Dec 16, 2020 6:00 pm
- Forum: Lewis Acids & Bases
- Topic: Ligands
- Replies: 6
- Views: 381
Re: Ligands
A ligand is anything that bonds to a coordinate covalent compound. Ligands always have a spare electron pair which allows them to bind and form a compound. Some ligands can be bidentate or tridentate meaning they have 2 electron pair donors or three.
- Wed Dec 16, 2020 5:59 pm
- Forum: Lewis Acids & Bases
- Topic: Acids & Bases
- Replies: 9
- Views: 651
Re: Acids & Bases
Theres many different types of ways to define an acid and a base. A Lewis base and acid, the base being the one that donates electrons while the acid is the one accepting. By the Bronsted definition, the acids are the ones releasing an H+ and bases accepting an H+.
- Wed Dec 16, 2020 5:57 pm
- Forum: Polyprotic Acids & Bases
- Topic: Which one is more acidic: H3PO3 or H3PO4
- Replies: 17
- Views: 1122
Re: Which one is more acidic: H3PO3 or H3PO4
Anytime you have hydrogens and oxygens and you are determining strength of acid, always look at the number of oxygen. When you have more oxygen it stabilizes the structure much better with more oxygen than less after losing a hydrogen.
- Sun Dec 06, 2020 8:18 pm
- Forum: Amphoteric Compounds
- Topic: Amphoteric - how to tell if it is an acid or base
- Replies: 4
- Views: 269
Re: Amphoteric - how to tell if it is an acid or base
When you are trying to determine amphoteric compound in a reaction always look for where the hydrogen goes. If it leaves one compound then that one is the acid and the other is the base. Look at the reactants and the products to figure that out.
- Sun Dec 06, 2020 8:16 pm
- Forum: Amphoteric Compounds
- Topic: Amphoteric
- Replies: 11
- Views: 675
Re: Amphoteric
Amphoteric compounds are compounds that can act as either bases or acids depending on what elements are around them. Amphiprotic compounds can accept and donate hydrogens.
- Sun Dec 06, 2020 8:09 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Why is HF not classified as a strong acid?
- Replies: 19
- Views: 945
Re: Why is HF not classified as a strong acid?
HF cannot be classified as a strong acid because fluorine has the highest electronegativity on the periodic table of element so it holds onto that hydrogen very tightly making it not a strong acid, but do not forget it is still an acid.
- Sun Dec 06, 2020 8:07 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Negative pH of acid
- Replies: 16
- Views: 634
Re: Negative pH of acid
There is no negative PH. It can only range to the scale of 0-14.
- Sun Dec 06, 2020 8:05 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Strengths of Acids: Polarity
- Replies: 6
- Views: 516
Re: Strengths of Acids: Polarity
When looking at the strength of acids always look at its ability to give off a hydrogen. When its a bigger a element it has longer bonds so it has a smaller bond on the hydrogens. But I see your point and yes stronger acids typically have a higher polarizability because it has more electrons and a l...
- Sun Nov 29, 2020 8:47 pm
- Forum: Hybridization
- Topic: Sapling #11
- Replies: 19
- Views: 797
Re: Sapling #11
Most important part is to first read the question and understand what they are asking. They say to look at a phosphorous atom so it is not difficult at all. Locate one of them and find how many electron dense regions there are. Phosphorous in this diagram has 3 single bonds and one lone pair so it h...
- Sun Nov 29, 2020 8:45 pm
- Forum: Hybridization
- Topic: Sapling #12
- Replies: 29
- Views: 961
Re: Sapling #12
When you're trying to find the hybridization orbitals just look for the amount of electron dense areas. C and O in that problem have 4 areas so you get sp3 because sp3 has 4 areas of electron density, S P P P being the 4 different orbitals that can have electrons.
- Sun Nov 29, 2020 8:41 pm
- Forum: Hybridization
- Topic: delocalized pi bonds
- Replies: 15
- Views: 519
Re: delocalized pi bonds
Delocalized pi bonds always happen with resonance of atoms that have multiple bonds, typically double bonds. They are also in a circular pattern such as a hexagonal shape, so if you have a carbon chain with the same amount of hydrogen chances are you have delocalized pi bonds.
- Sun Nov 29, 2020 8:35 pm
- Forum: Hybridization
- Topic: Definition of Hybridization
- Replies: 5
- Views: 275
Re: Definition of Hybridization
Hybridization is the explanation of what happens when you combine atoms to form a molecule. The bonds between atoms make hybridized orbitals because these atoms are being shared. There is no easy way to do it unless you practice and practice and you recognize molecules and their valence electrons by...
- Sun Nov 29, 2020 8:33 pm
- Forum: Hybridization
- Topic: Hybridization of Carbon
- Replies: 10
- Views: 307
Re: Hybridization of Carbon
The 3 from the sp3 comes from the 3 atomic orbitals that p has. For example D has 5 orbitals and f has 7 as well as s having one. S does not have a number because the one is just one so its just S.
- Sun Nov 22, 2020 7:02 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angle of Molecule
- Replies: 7
- Views: 242
Re: Bond Angle of Molecule
You got the answer correct because you chose the experimental value of the degrees when you have 2 lone pairs and 2 bonds. So both answers were acceptable.
- Sun Nov 22, 2020 7:00 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Lone Pairs
- Replies: 6
- Views: 299
Re: Lone Pairs
Lone pairs are diffuse in the sense they repulse each other more than bonding pairs. That is why the lone pairs affect the shape of some molecules because they repulse the bonding pairs so much.
- Sun Nov 22, 2020 6:59 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Shape
- Replies: 10
- Views: 365
Re: Shape
Since it has only bond its shape would be linear.
- Sun Nov 22, 2020 6:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: CH3F Molecular Shape
- Replies: 7
- Views: 1893
Re: CH3F Molecular Shape
CH3F is tetrahedral, the fluorine however affects the bond angle. I am not sure how much it changes it.
- Sun Nov 22, 2020 6:56 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 21
- Views: 634
Re: Bond Angles
You cannot determine bond angles from any molecular structure. You have to search it up because they are experimentally determined, but you can memorize them.
- Sun Nov 15, 2020 11:27 am
- Forum: Ionic & Covalent Bonds
- Topic: Electronegativity difference
- Replies: 12
- Views: 377
Re: Electronegativity difference
You can calculate it if you are given the table during a test. But you can always recognize ionic vs covalent by using the electronegativity trend. The most electronegativity is top right and the least being bottom left. So use this trend, and when elements are further away from each other you'll se...
- Sun Nov 15, 2020 11:24 am
- Forum: Dipole Moments
- Topic: Sapling number 17
- Replies: 10
- Views: 438
Re: Sapling number 17
CH4 exhibits LDF only because it is non polar. The reason why is because all the hydrogens have the same bond with the carbon and have the exact same pull. So there is induced dipole but there is nothing else.
- Sun Nov 15, 2020 11:20 am
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 19
- Views: 624
Re: Resonance
The reason why resonance lowers energy is due to the double bond that there is. Because of a bond having resonance, all the bond lengths become shorter due to partial bond lengths. Basically, now all the bonds are shorter because of the resonance.
- Sun Nov 15, 2020 11:16 am
- Forum: Octet Exceptions
- Topic: Identifying Radicals
- Replies: 24
- Views: 1026
Re: Identifying Radicals
The easiest way to identify a radical is to first count the amount of valence electrons. Once you do this, anytime you have an odd amount of electrons, it is a radical. But often, they can be balanced you may have just forgot to add or subtract electrons according to the charge.
- Sun Nov 15, 2020 11:15 am
- Forum: Octet Exceptions
- Topic: Valence electrons for Beryllium
- Replies: 2
- Views: 293
Re: Valence electrons for Beryllium
Beryllium will want to lose electrons and have 2 valence electrons. Beryllium is a cat anion and so to achieve a full outer shell, it will lose electrons from 2s2 to get to 1s2.
- Sun Nov 08, 2020 7:47 pm
- Forum: Sigma & Pi Bonds
- Topic: Sigma vs. Pi
- Replies: 20
- Views: 1131
Re: Sigma vs. Pi
Sigma bonds are much stronger because when they overlap each other, they have a higher strength. While Pi bonds are side by side thus having less connection and much less strength.
- Sun Nov 08, 2020 7:45 pm
- Forum: Electronegativity
- Topic: Noble Gases
- Replies: 40
- Views: 12406
Re: Noble Gases
Noble gases have a full valence electron shell, so they do not pair with anything unless electrons are forced onto it. Which requires quite a bit of energy and the electron is lost rapidly.
- Sun Nov 08, 2020 7:42 pm
- Forum: Lewis Structures
- Topic: Lewis Dot Structure
- Replies: 11
- Views: 371
Re: Lewis Dot Structure
When you are doing a lewis dot structure for one independent atom, then you put the electrons according to the outer shell of valence electrons. The order is typically one dot clockwise at each spot until you use all of your electrons. Say you have 5 electrons in the other shell which would be nitro...
- Sun Nov 08, 2020 7:41 pm
- Forum: Ionic & Covalent Bonds
- Topic: Identifying Ionic and Covalent Bonds
- Replies: 10
- Views: 208
Re: Identifying Ionic and Covalent Bonds
As people above have said, when you calculate the electronegativity, when it is above 2 it is a covalent bond and below 1.5 it is a ionic bond.
- Sun Nov 08, 2020 7:39 pm
- Forum: Ionic & Covalent Bonds
- Topic: Size of Bonds
- Replies: 28
- Views: 760
Re: Size of Bonds
Due to the weaker connection of having 2 electrons in a single compared compared to a double bond with 4 electrons, the double bond is shorter because there are more protons in the double bond compared to the single bond.
- Sun Nov 01, 2020 7:05 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: The equation
- Replies: 7
- Views: 603
Re: The equation
Any time you have a question that either gives or asks for the indeterminacy for velocity or position, then you know you will be using the Heisenberg Equation.
- Sun Nov 01, 2020 7:03 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbital vs. Subshell
- Replies: 13
- Views: 735
Re: Orbital vs. Subshell
S, P, D, and F are all subshells and within each sub shell you have an amount of orbitals. In S there is one orbital which has 2 electrons, P has 3 orbitals that can have 6 electrons, D has 5 orbitals which can have 10 electrons and finally f has 7 orbitals which can have a total of 14 electrons.
- Sun Nov 01, 2020 7:01 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Sapling #24
- Replies: 16
- Views: 435
Re: Sapling #24
Wave lengths can have no discrepancies. They have to have a consistent amplitude and wavelength, if these differ then it will not be correct. Also it must start from the top and end at the bottom for it to count as a wavelength.
- Sun Nov 01, 2020 7:00 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Orbitals and Electrons
- Replies: 9
- Views: 260
Re: Orbitals and Electrons
The Pauli Exclusion Principle states that orbitals can only have a maximum of 2 electrons per orbital and they almost must have opposing spins.
- Sun Nov 01, 2020 6:59 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: 4s and 3d
- Replies: 14
- Views: 405
Re: 4s and 3d
Always remember except for rare cases that electrons will always fill lower levels before they move onto higher levels. 4s is a higher energy level than 3d, hence the reason 3d fills first.
- Sun Oct 25, 2020 2:48 pm
- Forum: Photoelectric Effect
- Topic: Mass of atoms
- Replies: 18
- Views: 532
Re: Mass of atoms
Mass of atoms should always be in Kilograms. When it comes to electrons, neutrons and protons all are on the formula sheet, so you will know the masses of all the following. So undoubtedly you will not get the mass of any of these particles in anything but kilograms.
- Sun Oct 25, 2020 2:47 pm
- Forum: Photoelectric Effect
- Topic: Intensity vs. Frequency
- Replies: 22
- Views: 1659
Re: Intensity vs. Frequency
Frequency is the amount of waves that are being sent in a period of time. Intensity is the light that can increase but the photons rendered in light can increase which is how intensity increases.
- Sun Oct 25, 2020 2:40 pm
- Forum: DeBroglie Equation
- Topic: Using kg in DeBroglie Equation instead of g
- Replies: 3
- Views: 115
Re: Using kg in DeBroglie Equation instead of g
Planck's constant which is 6.626 times ten to the negative thirty fourth power has Joules. To cancel the joules, which is kilogram times m2 and s-2. This Kg needs to be removed to find the final frequency. You can only do this by having Kg at the denominator.
- Sun Oct 25, 2020 2:38 pm
- Forum: DeBroglie Equation
- Topic: Purpose of DeBroglie Equation
- Replies: 11
- Views: 506
Re: Purpose of DeBroglie Equation
The purpose of the De Broglie equation is supposed to find the wave like function of small atoms. You can use momentum with Planck's constant to find the frequency of a small particle.
- Sun Oct 25, 2020 2:36 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: #26 in sapling
- Replies: 3
- Views: 101
Re: #26 in sapling
First things first remember when you're finding the molar mass from a mol you have to initially use avogadros number to convert to grams. Then from grams convert to kilograms!
- Sat Oct 17, 2020 3:49 pm
- Forum: Einstein Equation
- Topic: Planck's Number
- Replies: 6
- Views: 287
Re: Planck's Number
Plancks constant which is 6.626 x 10 to the negative 34th power joules which is the electromagnetic radiation divided by frequency. This helps you find several other key parts of the Quantum World.
- Sat Oct 17, 2020 3:47 pm
- Forum: Einstein Equation
- Topic: m vs nm
- Replies: 66
- Views: 3208
Re: m vs nm
Meters is usually best, but nano meters works just as well for the final answer. You just have to make sure you're using scientific notation properly and you convert. Either works but more importantly focus on converting correctly.
- Sat Oct 17, 2020 3:46 pm
- Forum: Properties of Light
- Topic: Textbook Self Test 1b.3a
- Replies: 3
- Views: 97
Re: Textbook Self Test 1b.3a
Hello, once you have solved for the energy you have to find the longest wavelength of radiation which is the equation, I=hv. The I is the energy required to eject an electron, and the H being Planck's constant and V the wavelength.
- Sat Oct 17, 2020 3:42 pm
- Forum: Properties of Electrons
- Topic: Work function/Threshold Energy
- Replies: 19
- Views: 660
Re: Work function/Threshold Energy
Absolutely, work function and threshold energy are directly related. The work function is the amount of energy it takes to release an electron from a material, and the threshold energy is that amount of energy. Once the material passes that threshold of energy it immediately releases an electron.
- Sat Oct 17, 2020 3:40 pm
- Forum: Student Social/Study Group
- Topic: How are you studying?
- Replies: 204
- Views: 16953
Re: How are you studying?
Reading the textbook and taking notes. I write down all the formulas that are important and highlight them. I complete all the given homework assignments that were labeled in the textbook, and I follow answer that are also given and check my answers and the work behind it.
- Fri Oct 09, 2020 11:38 am
- Forum: SI Units, Unit Conversions
- Topic: Kg to g
- Replies: 13
- Views: 2229
Re: Kg to g
If you have 10.6 KG and you're converting to grams just move the decimal 3 places to the right because there are 1000grams in one KG. Its a simple way to do it.
- Fri Oct 09, 2020 11:37 am
- Forum: Significant Figures
- Topic: Which number determines sig figs of the answer?
- Replies: 26
- Views: 825
Re: Which number determines sig figs of the answer?
When you are multiplying it is determined by the number with the least amount of significant digits.