Search found 114 matches
- Sat Mar 14, 2020 5:14 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Ka and Kb
- Replies: 4
- Views: 520
Re: Ka and Kb
Yes, Ka is the dissociation constant based on the H+ concentration and Kb is the dissociation constant based on the OH- concentration.
- Sat Mar 14, 2020 5:10 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Equilibrium Constants
- Replies: 15
- Views: 976
Re: Equilibrium Constants
Yes make sure the equation is balanced so that you can be sure that the exponents are correct and the same as the stoichiometric coefficients.
- Sat Mar 14, 2020 5:07 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Gibbs free energy
- Replies: 9
- Views: 743
Re: Gibbs free energy
deltaG* implies the standard conditions of 1 M concentration, 1 atm pressure, and 25 degrees Celsius.
- Sat Mar 14, 2020 5:04 pm
- Forum: Phase Changes & Related Calculations
- Topic: Negative Work
- Replies: 18
- Views: 1528
Re: Negative Work
The value for work would be negative if the system was doing work on the surroundings.
- Sat Mar 14, 2020 4:58 pm
- Forum: First Order Reactions
- Topic: First order rxns
- Replies: 6
- Views: 437
Re: First order rxns
If the concentration and the rate are being changed by the same factor, then it is a first order reaction.
- Sat Mar 14, 2020 4:56 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: inert gases
- Replies: 6
- Views: 435
Re: inert gases
Kaylee Clarke 1G wrote:what of the elements such as platinum that seem to be attached to a cell diagram?
Platinum is used because it is an inert electrode.
- Sun Mar 08, 2020 6:51 pm
- Forum: General Rate Laws
- Topic: Rate limiting step
- Replies: 12
- Views: 879
Rate limiting step
What is a rate limiting step and how do we find it?
- Sun Mar 08, 2020 6:15 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: K’ for multi step reactions
- Replies: 1
- Views: 163
K’ for multi step reactions
How do you find K’ for multi step reactions?
- Sun Mar 08, 2020 6:11 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: How to determine order
- Replies: 3
- Views: 259
How to determine order
What are the ways/steps to determine the order of a reaction?
- Sun Mar 08, 2020 6:05 pm
- Forum: General Rate Laws
- Topic: Reverse reaction rate
- Replies: 1
- Views: 154
Reverse reaction rate
Why does the rate for the reverse reaction use K’ instead of K?
- Sun Mar 08, 2020 6:01 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Molecularity
- Replies: 12
- Views: 844
Molecularity
What is molecularity and it’s relation to rate laws?
- Sun Mar 01, 2020 9:10 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: n value
- Replies: 9
- Views: 613
n value
How is the n value in deltaG=-nFE(cell) calculated?
- Sun Mar 01, 2020 9:09 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Standard Cell Potential for Oxidation Half-Reactions
- Replies: 3
- Views: 230
Standard Cell Potential for Oxidation Half-Reactions
Is the sign for standard energy potential switched for oxidation half reactions?
- Sun Mar 01, 2020 8:58 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Cell Diagram Comma vs Line
- Replies: 5
- Views: 357
Re: Cell Diagram Comma vs Line
Comma is used if there are multiple species in the same phase while a line is used to separate phases such as aqueous, gas, liquid, and solid.
- Sun Mar 01, 2020 8:55 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Oxidation Numbers
- Replies: 5
- Views: 446
Re: Oxidation Numbers
Keep the overall charge of the molecule in mind and use typical oxidation numbers such as -2 for oxygen and +1 for group 1A elements.
- Sun Mar 01, 2020 8:48 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: when to use K or Q
- Replies: 18
- Views: 1128
Re: when to use K or Q
Q is used at any point in the reaction when it is not at equilibrium.
- Sun Mar 01, 2020 8:46 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: cell diagrams
- Replies: 4
- Views: 398
Re: cell diagrams
Use platinum since it is an inert electrode.
- Sun Feb 23, 2020 11:53 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Electron Transfer
- Replies: 3
- Views: 264
Electron Transfer
Why cannot the electron transfer of one cell be measured?
- Sun Feb 23, 2020 11:28 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Max Cell Potential and Free Energy Difference
- Replies: 2
- Views: 247
Max Cell Potential and Free Energy Difference
How are max cell potential and free energy difference between reactants and products related?
- Sun Feb 23, 2020 9:10 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation States
- Replies: 7
- Views: 423
Re: Oxidation States
Use typically known oxidation states (such as -2 for oxygen) and work backwards from the overall charge to find the oxidation state of the remaining element(s).
- Sun Feb 23, 2020 9:07 pm
- Forum: Balancing Redox Reactions
- Topic: Alkaline
- Replies: 3
- Views: 318
Alkaline
What do you do when balancing redox reactions for alkaline solutions? How is it difference from acidic solutions?
- Sun Feb 23, 2020 9:06 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: l vs ll
- Replies: 5
- Views: 372
Re: l vs ll
A single line represents separation of phases or a porous disk while a double line represents a salt bridge.
- Sun Feb 16, 2020 8:01 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: endo/exo and temp
- Replies: 12
- Views: 1165
Re: endo/exo and temp
In endothermic reactions, heat is like a reactant. This means that if heat is added, there are more reactants, which means that reaction will shift towards the products in the forward direction.
- Sun Feb 16, 2020 7:56 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Different Types of Entropies
- Replies: 6
- Views: 553
Re: Different Types of Entropies
The entropy of the system and surroundings added up equal the entropy of the surroundings. In cases where the entropy of the surroundings is 0, the entropy of the system equals -1*entropy of the surroundings.
- Sun Feb 16, 2020 7:54 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond Enthalpies with Molecules
- Replies: 4
- Views: 303
Re: Bond Enthalpies with Molecules
Use the given positive values for all the bond enthalpies and use the equation (bonds broken)-(bonds formed) to calculate the overall delta h.
- Sun Feb 16, 2020 5:31 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: R constants
- Replies: 40
- Views: 2338
Re: R constants
Make sure your units cancel out and the unit for pressure (bar, atm, Torr) matches the unit for the pressure value in the question.
- Sun Feb 16, 2020 5:27 pm
- Forum: Calculating Work of Expansion
- Topic: Reversible vs Irreversible
- Replies: 13
- Views: 900
Re: Reversible vs Irreversible
Reversible: w=-nRT(ln(v2/v1))
Irreversible: w=-p(delta v)
Irreversible: w=-p(delta v)
- Mon Feb 10, 2020 3:12 am
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Internal Energy
- Replies: 4
- Views: 360
Re: Internal Energy
I was just on this problem and luckily found this post. Are we supposed to know that 1atm is equivalent to 760 torr or is that somewhere on the equation sheet? Also how do we convert from L*atm to kJ? Both conversions are given on the constants and equations sheet. 1 L.atm = 101.325 J 1 atm = 760 t...
- Mon Feb 10, 2020 3:10 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Strong Acids
- Replies: 6
- Views: 344
Re: Strong Acids
Since strong acids dissociate completely, a Ka value is usually not given.
- Mon Feb 10, 2020 3:02 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: delta U = 0
- Replies: 2
- Views: 133
delta U = 0
What are the different situations in which delta U can equal 0?
- Mon Feb 10, 2020 3:00 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: delta h rxn at different temperatures
- Replies: 1
- Views: 112
delta h rxn at different temperatures
What is the setup for when the delta h rxn is given at a specific temperature but we are being asked to calculate the delta h rxn at another temperature?
- Mon Feb 10, 2020 2:54 am
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: delta s = q(rev)/T
- Replies: 1
- Views: 61
delta s = q(rev)/T
Since the q value in the delta s = q(rev)/T equation is the energy transferred reversibly as heat, is there a separate equation needed to find q for a reversible reaction (similar to how there is a different equation to find w if the reaction is reversible)?
- Mon Feb 10, 2020 2:52 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: when to change sign of enthalpies
- Replies: 7
- Views: 409
Re: when to change sign of enthalpies
Yes, taking the reverse reaction allows the products and reactants to switch sides so that things can get canceled out as needed.
- Mon Feb 10, 2020 2:50 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: q=CΔT
- Replies: 5
- Views: 344
Re: q=CΔT
The heat capacity for the calorimeter takes the mass and everything else into account already.
- Sun Feb 02, 2020 9:08 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Changing the energy of a system
- Replies: 9
- Views: 357
Changing the energy of a system
What are the three ways to change the energy of a system?
- Sun Feb 02, 2020 9:06 pm
- Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
- Topic: Reaction constant P
- Replies: 3
- Views: 118
Reaction constant P
Why is P*delta V significant for changes in the number of moles of gas and insignificant for solids and liquids?
- Sun Feb 02, 2020 9:00 pm
- Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
- Topic: Boltzmann Equation [ENDORSED]
- Replies: 1
- Views: 342
Boltzmann Equation [ENDORSED]
What is the difference between the "small" and "large" errors in s and how does that influence whether a property is thermodynamic or statistical?
- Sun Feb 02, 2020 8:58 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: negative delta U value
- Replies: 2
- Views: 72
negative delta U value
Why do we not know if a reaction will occur just because the delta U value is negative?
- Sun Feb 02, 2020 8:48 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Hess's Law
- Replies: 4
- Views: 299
Re: Hess's Law
Also make sure to check if the the reactants and products are on their appropriate sides across all the equations before making changes to the equations.
- Sun Jan 26, 2020 12:44 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Exceptions to Hess's Law
- Replies: 1
- Views: 151
Exceptions to Hess's Law
Are there any situations where you would not be able to simply "add" chemical reactions together to determine overall delta h?
- Sun Jan 26, 2020 12:29 pm
- Forum: Phase Changes & Related Calculations
- Topic: Heat vs temperature
- Replies: 6
- Views: 366
Heat vs temperature
During lecture, there was a slide that mentioned that because heat is required during melting or boiling, the temperature of a sample remains constant even though heat is being added. Can someone please explain what this means?
- Sun Jan 26, 2020 12:21 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Br2(l) --> 2Br(g)
- Replies: 2
- Views: 561
Br2(l) --> 2Br(g)
For the reaction Br2(l) --> 2Br(g), how do you know which phase change enthalpies to use (why is it delta h vap + delta h bond)?
- Sun Jan 26, 2020 11:47 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: bond enthalpies
- Replies: 2
- Views: 136
Re: bond enthalpies
In the example that Dr. Lavelle used during lecture, drawing the Lewis structures reveals that the double bond between the carbons in ch2 is broken since the product (ch3ch2br) only has a single bond between the carbons. You would have to compare the Lewis structures of the reactants and the product...
- Sun Jan 26, 2020 11:44 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: state functions
- Replies: 4
- Views: 174
Re: state functions
When is it a state function, you only need to take the initial and final states into consideration instead of all the intermediate pathways as well. This makes it easier to calculate change.
- Mon Jan 20, 2020 2:13 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Solids and Liquids in K
- Replies: 3
- Views: 192
Re: Solids and Liquids in K
Liquids (solvents) are usually in excess in the reaction, so they are not included because there is no significant change in their concentrations.
- Mon Jan 20, 2020 2:00 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: K value at a specific temp
- Replies: 6
- Views: 274
Re: K value at a specific temp
The basic idea is that K values change based on the temperature.
- Mon Jan 20, 2020 1:56 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Endothermic Reactions
- Replies: 4
- Views: 241
Endothermic Reactions
Why does adding heat to a reaction drive product formation?
- Mon Jan 20, 2020 1:51 pm
- Forum: Ideal Gases
- Topic: R constant for PV=nRT
- Replies: 7
- Views: 484
Re: R constant for PV=nRT
The R values are constant and change based on the units of pressure being used.
- Mon Jan 20, 2020 1:49 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: X approx check
- Replies: 2
- Views: 198
Re: X approx check
Since values smaller than 10^-3 can typically allow the approximation method to be used, if the value is less than but somewhat close to 10^-3, you should definitely check to be sure.
- Sun Jan 12, 2020 7:47 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Units and Conversions of Kp
- Replies: 3
- Views: 115
Re: Units and Conversions of Kp
Just make sure the units are the same throughout, which means that the R value with the same unit is used in the equation.
- Sun Jan 12, 2020 7:41 pm
- Forum: Ideal Gases
- Topic: PV = nRT Confusion
- Replies: 4
- Views: 239
Re: PV = nRT Confusion
By rearranging the ideal gas equation, n/v can be isolated for which means that the concentration can be calculated for because n/v is the concentration/molarity.
- Sun Jan 12, 2020 7:38 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Thinking point 5J
- Replies: 4
- Views: 141
Re: Thinking point 5J
Since solids technically do not have a concentration, they are not involved in equilibrium constant equations. This means that equilibrium constants are the same even if the solid is removed.
- Sun Jan 12, 2020 7:34 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: stoichiometric coefficients
- Replies: 5
- Views: 363
Re: stoichiometric coefficients
Stoichiometric coefficients are the exponents that show that there multiples quantities of the substance. In this case, the concentration values are raised to the power of the stoichiometric coefficients.
- Sun Jan 12, 2020 7:23 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Difference between Kc/Kp and Q
- Replies: 2
- Views: 118
Re: Difference between Kc/Kp and Q
Q is when the values used at the concentrations at a specific time, not the equilibrium values at concentration. Kc and Kp use the concentration values at equilibrium.
- Sun Dec 08, 2019 10:20 am
- Forum: Amphoteric Compounds
- Topic: amphiprotic vs amphoteric
- Replies: 2
- Views: 281
amphiprotic vs amphoteric
why are amphiprotic always amphoteric but not the other way around?
- Sun Dec 08, 2019 10:19 am
- Forum: Amphoteric Compounds
- Topic: examples
- Replies: 3
- Views: 338
examples
what are the reactions for some amphoteric compounds showing that they can act as acids and bases?
- Sun Dec 08, 2019 9:41 am
- Forum: Hybridization
- Topic: lone pairs in hybridization
- Replies: 6
- Views: 571
lone pairs in hybridization
how are lone pair shown in hybridization?
- Sun Dec 08, 2019 9:41 am
- Forum: Hybridization
- Topic: pi bonds
- Replies: 12
- Views: 719
pi bonds
why are pi bonds shown in the p orbital?
- Sun Dec 08, 2019 9:37 am
- Forum: Dipole Moments
- Topic: Cancelling dipole moments
- Replies: 11
- Views: 4810
Re: Cancelling dipole moments
If the shape is tetrahedral and all attachments are the same, dipoles cancel.
- Sun Dec 01, 2019 9:22 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: NO2-
- Replies: 1
- Views: 102
NO2-
Is nitro a mono, bi, or polydentate? Which element's lone pairs are considered?
- Sun Dec 01, 2019 9:15 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate
- Replies: 2
- Views: 216
Polydentate
How do you determine if a ligand is polydentate?
- Sun Dec 01, 2019 4:36 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: Inductive Effect
- Replies: 1
- Views: 74
Inductive Effect
Can someone please explain the inductive effect in relation to delocalization.
- Sun Dec 01, 2019 4:25 pm
- Forum: Properties & Structures of Inorganic & Organic Bases
- Topic: Metal Oxide and Water
- Replies: 1
- Views: 116
Metal Oxide and Water
What happens when a metal oxide reacts with water? Is a base produced or does the metal oxide break down into a metal cation and hydroxide ions?
- Sun Dec 01, 2019 4:17 pm
- Forum: Naming
- Topic: Order of ligands in formulas for coordination compounds
- Replies: 4
- Views: 244
Re: Order of ligands in formulas for coordination compounds
Also, the anion is written before the neutral ligand.
- Sun Dec 01, 2019 2:17 pm
- Forum: Hybridization
- Topic: Hybrid Orbitals
- Replies: 4
- Views: 263
Re: Hybrid Orbitals
The extra orbital is needed for the 4th electron in an sp2 orbital, which can hold 3 electrons. The un-hybridized p electron is unpaired.
- Sun Dec 01, 2019 2:10 pm
- Forum: Naming
- Topic: How to Find the Roman Numeral
- Replies: 4
- Views: 349
Re: How to Find the Roman Numeral
Work backwards from the overall charge and charge of the ligands to find the charge on the metal.
- Sun Nov 24, 2019 10:16 pm
- Forum: Biological Examples
- Topic: Porphyrin ligand-tetradentate
- Replies: 2
- Views: 354
Porphyrin ligand-tetradentate
Can someone please example the porphyrin ligand-tetradentate example from lecture with relation to heme complexes?
- Sun Nov 24, 2019 10:14 pm
- Forum: Biological Examples
- Topic: Transition Metals and Oxidation States
- Replies: 1
- Views: 138
Transition Metals and Oxidation States
What is the biological benefit of transition metals having many oxidation states?
- Sun Nov 24, 2019 10:13 pm
- Forum: Naming
- Topic: Di-, Tri-, Tetra- vs Bis-, Tris-, Tetrakis-
- Replies: 11
- Views: 1007
Di-, Tri-, Tetra- vs Bis-, Tris-, Tetrakis-
When are bis-, tris-, tetrakis- used instead of di-, tri-, tetra-?
- Sun Nov 24, 2019 10:11 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination Sphere
- Replies: 1
- Views: 151
Coordination Sphere
Why are bound ligands a part of the coordination sphere?
- Sun Nov 24, 2019 10:05 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: bronsted acid
- Replies: 5
- Views: 293
Re: bronsted acid
A bronsted acid is a chemical species that can donate a proton. An example is CH3COOH (acetic acid).
- Sun Nov 24, 2019 10:02 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Hybridization
- Replies: 7
- Views: 467
Re: Hybridization
Hybridization makes it easier to see the different types of bonds that are present. It is also meant to show that the "fusing" of orbitals affects shapes and ability to bond.
- Sun Nov 17, 2019 11:58 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Repulsion strength
- Replies: 5
- Views: 334
Re: Repulsion strength
Closer because radius is a variable in Coulomb's Law.
- Sun Nov 17, 2019 11:39 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Axial and Equatorial Lone Pairs
- Replies: 1
- Views: 146
Axial and Equatorial Lone Pairs
How do we determine the different effects of axial and equatorial lone pairs on molecule shape?
- Sun Nov 17, 2019 11:29 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Resonance and VSEPR
- Replies: 9
- Views: 611
Resonance and VSEPR
Are resonance structures considered when determining molecular shape?
- Sun Nov 17, 2019 11:27 pm
- Forum: Dipole Moments
- Topic: Hydrogen Bonds and Polarity
- Replies: 1
- Views: 94
Hydrogen Bonds and Polarity
Is there formation of hydrogen bonds related in any way to polarity?
- Sun Nov 17, 2019 11:23 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Radicals and molecular shape
- Replies: 5
- Views: 379
Re: Radicals and molecular shape
Radicals count as 1 region of electron density but the repulsion is not as great as that of a lone pair.
- Sun Nov 17, 2019 11:22 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Trans vs Cis molecules
- Replies: 2
- Views: 126
Re: Trans vs Cis molecules
The cis molecule in the example during lecture was polar while the trans molecule was non-polar because the dipole moments canceled out.
- Sun Nov 10, 2019 5:54 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionization of Nitrogen vs Oxygen
- Replies: 11
- Views: 1672
Re: Ionization of Nitrogen vs Oxygen
The half-filled orbitals for nitrogen and more stable and harder to remove an electron from than the 1 orbital in oxygen that has 2 paired electrons.
- Sun Nov 10, 2019 5:28 pm
- Forum: Electronegativity
- Topic: Differences in Electronegativity
- Replies: 5
- Views: 389
Re: Differences in Electronegativity
You can use the general trends in increasing and decreasing electronegative for the periodic table can help identify the general differences in electronegativity between 2 elements without needing to know the exact values.
- Sun Nov 10, 2019 5:18 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Energy Levels
- Replies: 4
- Views: 353
Re: Energy Levels
By using (-hR/n^2) for the final n value minus (-hr/n^2) for the initial n value, you can find the energy difference. If the energy difference and one of the n values are known, you can rearrange the equation to find the other n value since -hR is a constant value.
- Sun Nov 10, 2019 4:56 pm
- Forum: Empirical & Molecular Formulas
- Topic: Empirical formula
- Replies: 2
- Views: 207
Re: Empirical formula
If you are given the mass of the reactants, convert it to moles of each reactant using the molar mass from the periodic table. Then divide each molar value by the smallest molar value and multiply to get whole numbers if necessary.
- Sun Nov 10, 2019 4:54 pm
- Forum: Resonance Structures
- Topic: Resonance Structures
- Replies: 3
- Views: 147
Re: Resonance Structures
For boron, not having an octet and having just 6 shared electrons makes it formal charge 0 since it has 6 valence electrons. This is favorable for boron rather than having a complete octet.
- Sun Nov 10, 2019 4:51 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Using the equation
- Replies: 2
- Views: 222
Re: Using the equation
You use the equation to find uncertainty in position or velocity, depending on what is given. If, for example, the velocity is given as 10 +/- 2 m/s, delta(velocity) would be 4 m/s and the question may ask you to find the difference in position (delta(position)) while the mass remains constant.
- Sun Nov 03, 2019 6:36 pm
- Forum: Lewis Structures
- Topic: Single bond
- Replies: 2
- Views: 164
Re: Single bond
Yes. A bond represents 2 electrons being shared.
- Sun Nov 03, 2019 5:50 pm
- Forum: Lewis Structures
- Topic: 2B.19
- Replies: 1
- Views: 154
Re: 2B.19
Triple bonds allow the octet to be satisfied for each element.
- Sun Nov 03, 2019 5:49 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: Dilution Equation
- Replies: 4
- Views: 314
Re: Dilution Equation
Make sure you keep your units constant though. In this case, your answer would be in mL too.
- Sun Nov 03, 2019 3:21 pm
- Forum: Lewis Structures
- Topic: Lewis structure
- Replies: 3
- Views: 106
Re: Lewis structure
You should try to get the central atom to have a formal charge of 0, and if it is allowed to have an expanded octet, it can have more than 8 electrons.
- Sun Nov 03, 2019 3:14 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: 1B.26
- Replies: 4
- Views: 184
1B.26
A bowling ball of mass 8.00 kg is rolled down a bowling alley lane at 5.00 +/-5.0 m/s. What is the minimum uncertainty in its position?
Is the delta velocity 5.0 m/s or 10 m/s because it says +/- 5.0 m/s?
Is the delta velocity 5.0 m/s or 10 m/s because it says +/- 5.0 m/s?
- Sun Nov 03, 2019 3:11 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 1E.13
- Replies: 2
- Views: 226
Re: 1E.13
For silver, I would suggest writing the expected electron configuration and then switching the electron from the 5s to the 4d (since you're trying to get 4d^10). For beryllium, just go through the 1s, 2s order.
- Sun Oct 27, 2019 3:17 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge
- Replies: 5
- Views: 347
Re: Formal Charge
Formal charge indicates the gain or loss of electrons that occurs when a covalent bond is formed since the electrons are shared in a covalent bond.
- Sun Oct 27, 2019 3:16 pm
- Forum: Lewis Structures
- Topic: Lewis Structure of Ions
- Replies: 6
- Views: 394
Re: Lewis Structure of Ions
Yes, the brackets are placed around the entire structure with the charge in the corner to show the whole molecule's charge.
- Sun Oct 27, 2019 3:08 pm
- Forum: Lewis Structures
- Topic: Drawing the structure
- Replies: 7
- Views: 439
Re: Drawing the structure
That shape is the resonance hybrid and it depicts the bond length as relatively equal rather than some being stronger than others. For example, the c-c single bond in benzene has a length of 1.54 Angstroms while the c=c double bond in benzene has a length of 1.34 Angstroms. Experimentally, however, ...
- Sun Oct 27, 2019 2:48 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Central atom
- Replies: 8
- Views: 368
Re: Central atom
The formal charge of the central atom might not always be 0, but as long as the the sum of all the formal charges add up to the charge of the overall molecule, it's fine.
- Sun Oct 27, 2019 2:45 pm
- Forum: Resonance Structures
- Topic: Resonance
- Replies: 8
- Views: 227
Re: Resonance
The purpose is to show that there may different possible ways that the bonds can be formed while the overall charges remain the same.
- Sun Oct 27, 2019 2:41 pm
- Forum: Trends in The Periodic Table
- Topic: Cations
- Replies: 8
- Views: 392
Re: Cations
Since there are fewer electrons but the same number of protons, the protons have a greater pull on the fewer number of electrons, therefore those electrons are drawn in closer to the nucleus, making the size of the cation smaller.
- Sat Oct 19, 2019 2:09 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Magnetic Quantum Number (ml)
- Replies: 2
- Views: 188
Magnetic Quantum Number (ml)
How do we know if the magnetic quantum number for orientation for the p orbital is -1,0,1 in relation to px, py, and pz?
- Sat Oct 19, 2019 2:06 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: spin state (ms) quantum number
- Replies: 2
- Views: 166
spin state (ms) quantum number
Is there any way to know whether the electrons ms quantum number of -1/2 or +1/2?
- Sat Oct 19, 2019 2:03 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Hund's rule
- Replies: 5
- Views: 166
Re: Hund's rule
The parallel spins are from electrons occupying empty orbitals first. After that, they start to pair up, which leads to opposite spins.
- Sat Oct 19, 2019 2:01 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Paired vs Parallel electrons
- Replies: 5
- Views: 139
Re: Paired vs Parallel electrons
Electrons occupy orbital individually first so the spins are parallel. Once the available orbitals have been filled, they start pairing up, which is where the opposite spins come from.