Search found 104 matches
- Sun Mar 15, 2020 11:52 pm
- Forum: Zero Order Reactions
- Topic: Half life
- Replies: 19
- Views: 899
Half life
Where do you start when you determine the half life for a zero order reaction?
- Sun Mar 15, 2020 11:42 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Delta U
- Replies: 6
- Views: 465
Delta U
When calculating the internal energy of the system how do you know when to change the sign of q/w?
- Sun Mar 15, 2020 11:25 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: ΔGionization
- Replies: 10
- Views: 818
ΔGionization
Is there a different way to calculate ΔG ionization?
- Sun Mar 15, 2020 11:19 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Lewis structures
- Replies: 4
- Views: 366
Lewis structures
How can you tell if a reaction is endothermic or exothermic with just the lewis structures of the species?
- Sun Mar 15, 2020 11:10 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: reverse half reaction
- Replies: 4
- Views: 418
reverse half reaction
How do you know which half redox reaction to reverse and change the sign of the potential?
- Sun Mar 08, 2020 11:52 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Concentration Cell
- Replies: 5
- Views: 456
Concentration Cell
How does a concentration cell work?
- Sun Mar 08, 2020 11:51 pm
- Forum: General Rate Laws
- Topic: Amount of product formed
- Replies: 2
- Views: 181
Amount of product formed
Why is it easier to study initial rate when little product formed?
- Sun Mar 08, 2020 11:41 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Limit on reaction
- Replies: 1
- Views: 143
Limit on reaction
How is the reaction rate limited by K?
- Sun Mar 08, 2020 11:33 pm
- Forum: General Rate Laws
- Topic: Enzyme saturation
- Replies: 6
- Views: 374
Enzyme saturation
What does the saturation of an enzyme contribute to the rate of reaction?
- Sun Mar 08, 2020 11:29 pm
- Forum: General Rate Laws
- Topic: Pseudo rate law
- Replies: 3
- Views: 201
Pseudo rate law
Can someone explain what psuedo rate laws are and why they're significant?
- Sun Mar 01, 2020 11:58 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: calomel electrode
- Replies: 1
- Views: 149
Re: calomel electrode
It's a type of half cell in which the electrode is mercury coated with calomel and the electrolyte is a solution of potassium chloride and saturated calomel and used to measure pH and electrical potentials in solutions.
- Sun Mar 01, 2020 11:51 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Overall reaction order
- Replies: 3
- Views: 289
Overall reaction order
What is m in the overall reaction order equation
- Sun Mar 01, 2020 11:45 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: observing initial rates
- Replies: 3
- Views: 277
observing initial rates
Why is it easier to observe initial rates when t is close to t=0
- Sun Mar 01, 2020 11:38 pm
- Forum: First Order Reactions
- Topic: First order plot
- Replies: 3
- Views: 257
First order plot
What does the straight line plot of the natural log of reactants vs. time say about the reaction?
- Sun Mar 01, 2020 11:34 pm
- Forum: First Order Reactions
- Topic: First Order Reaction
- Replies: 4
- Views: 367
First Order Reaction
What are characteristics that indicate a first order reaction
- Thu Feb 27, 2020 9:32 am
- Forum: General Rate Laws
- Topic: Unique Rate
- Replies: 4
- Views: 342
Unique Rate
What is the unique rate equation telling us?
- Mon Feb 24, 2020 10:45 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Free energy difference
- Replies: 2
- Views: 155
Free energy difference
What does it mean by max cell potential is related to free energy difference between reactants and products?
- Mon Feb 24, 2020 10:44 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: work max
- Replies: 2
- Views: 179
work max
What is the maximum work that is done in a system?
- Mon Feb 24, 2020 10:37 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Usage for Nernst equation
- Replies: 7
- Views: 618
Usage for Nernst equation
What does it mean by non standard conditions when determining the direction of electron transfer?
- Mon Feb 24, 2020 10:35 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Salt bridge
- Replies: 6
- Views: 433
Salt bridge
What does the salt bridge do in the cell diagram?
- Mon Feb 24, 2020 10:29 am
- Forum: Balancing Redox Reactions
- Topic: Platinum in cell diagram
- Replies: 10
- Views: 712
Platinum in cell diagram
Why do we use Platinum when drawing the cell diagram?
- Sun Feb 16, 2020 11:34 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Signs for Gibbs Free Energy
- Replies: 11
- Views: 648
Signs for Gibbs Free Energy
What does it mean when Gibbs Free Energy is negative or positive?
- Sun Feb 16, 2020 10:50 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: ΔU Equal 0
- Replies: 4
- Views: 718
ΔU Equal 0
If ΔU is zero why does the gas expand
- Sun Feb 16, 2020 10:28 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: Positional entropy
- Replies: 3
- Views: 375
Positional entropy
What does positional entropy mean and what’s the difference from thermal entropy?
- Sun Feb 16, 2020 8:34 pm
- Forum: Calculating Work of Expansion
- Topic: Work without volume
- Replies: 5
- Views: 375
Work without volume
Can we calculate work without knowing change in volume?
- Sun Feb 16, 2020 8:26 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Irreversible isothermal expansion of gas
- Replies: 4
- Views: 257
Irreversible isothermal expansion of gas
How do you solve for the total change in entropy for an isothermally irreversible free expansion of gas?
- Sun Feb 09, 2020 10:35 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Comparing entropy change
- Replies: 2
- Views: 115
Comparing entropy change
How would you be able to tell that an entropy change is larger or smaller?
- Sun Feb 09, 2020 10:33 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Intensive
- Replies: 8
- Views: 474
Intensive
what does it mean when it says that entropy is an intensive property?
- Sun Feb 09, 2020 10:30 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: Gas v Liquids
- Replies: 4
- Views: 209
Gas v Liquids
Why do gases have a higher entropy than liquids?
- Sun Feb 09, 2020 10:19 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: positive-negative entropy
- Replies: 1
- Views: 130
positive-negative entropy
What are some qualities of a reaction that would determine whether the entropy of the reaction is positive or negative?
- Sun Feb 09, 2020 9:58 pm
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: use for a calorimeter?
- Replies: 2
- Views: 74
Re: use for a calorimeter?
Calorimeters measure the heat involved in a chemical reaction. We would use them with exothermic reactions since the solution is absorbing the heat that is produced by the reaction, increasing its temperature.
- Sun Feb 02, 2020 7:29 pm
- Forum: Phase Changes & Related Calculations
- Topic: State functions
- Replies: 7
- Views: 431
State functions
What is the importance of state functions in a system?
- Sun Feb 02, 2020 7:25 pm
- Forum: Calculating Work of Expansion
- Topic: Expansion/Extension
- Replies: 2
- Views: 83
Expansion/Extension
What are examples for work of expansion and work of extension?
- Sun Feb 02, 2020 7:20 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: 4A1
- Replies: 2
- Views: 73
4A1
What kind of system is a bomb calorimeter in which benzene is burned? and why?
- Sun Feb 02, 2020 6:54 pm
- Forum: General Science Questions
- Topic: Midterm
- Replies: 17
- Views: 918
Re: Midterm
Will they post practice midterm problems on chemistry community like last quarter?
- Sun Feb 02, 2020 6:50 pm
- Forum: General Science Questions
- Topic: Midterms
- Replies: 22
- Views: 863
Re: Midterms
MTanikella_1K wrote:The midterm will cover content from outlines 1-3 and part of outline 4.
Do you know until which focus of outline 4?
- Sun Jan 26, 2020 7:06 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kp to Kc
- Replies: 11
- Views: 529
Kp to Kc
If H2O is a gas in Kp, would it be included in the Kc calculation since it's a gas?
- Sun Jan 26, 2020 6:49 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Delta U
- Replies: 3
- Views: 167
Delta U
Is there a difference between delta H and delta U?
- Sun Jan 26, 2020 6:14 pm
- Forum: Phase Changes & Related Calculations
- Topic: Phase changes
- Replies: 8
- Views: 167
Phase changes
How do phase changes play a role in standard enthalpy calculations?
- Sun Jan 26, 2020 5:28 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: pH
- Replies: 7
- Views: 243
pH
How would you find the pH of a solution only given the pKa?
- Sun Jan 26, 2020 5:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Pressure and equilibrium
- Replies: 9
- Views: 238
Pressure and equilibrium
What effect does pressure have on the equilibrium of the reaction?
- Sun Jan 19, 2020 11:54 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Adding a catalyst
- Replies: 7
- Views: 262
Adding a catalyst
How will adding a catalyst change a reaction's equilibrium state?
- Sun Jan 19, 2020 11:49 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Halogens
- Replies: 2
- Views: 90
Halogens
What role to halogens play when it comes to determining the equilibria of a reaction?
- Sun Jan 19, 2020 11:38 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5% rule
- Replies: 2
- Views: 113
5% rule
What is this rule telling us?
- Sun Jan 19, 2020 11:36 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Q
- Replies: 6
- Views: 326
Q
When is Q used and what's the difference between it and K?
- Sun Jan 19, 2020 11:12 pm
- Forum: Ideal Gases
- Topic: Partial Pressures
- Replies: 4
- Views: 173
Partial Pressures
What happens to the other reactant partial pressure when one of the reactant partial pressures increases?
- Sun Jan 12, 2020 5:03 pm
- Forum: Ideal Gases
- Topic: P=(n/v)RT
- Replies: 12
- Views: 925
Re: P=(n/v)RT
I think it just means concentration multiplied by the constant and temperature
- Sun Jan 12, 2020 4:59 pm
- Forum: Ideal Gases
- Topic: Kc and Kp
- Replies: 8
- Views: 235
Re: Kc and Kp
Kc also uses brackets whereas Kp uses parentheses
- Sun Jan 12, 2020 4:57 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc
- Replies: 5
- Views: 204
Kc
So solids and aqueous solutions can be used to solve for Kc?
- Sun Jan 12, 2020 4:53 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Thinking point 5J
- Replies: 4
- Views: 111
Thinking point 5J
"Suppose one of the products of a reaction at equilibrium is a pure solid. How will the equilibrium be affected if some of the solid is removed? If all the solid is removed?"
- Sun Jan 12, 2020 4:38 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Finding K: liquids and aqueous
- Replies: 7
- Views: 221
Finding K: liquids and aqueous
Why do we keep aqueous solutions in the concentration equations and not liquids?
- Sun Dec 08, 2019 10:16 pm
- Forum: Student Social/Study Group
- Topic: Week 10 Chemistry Community
- Replies: 9
- Views: 699
Re: Week 10 Chemistry Community
AGaeta_4E wrote:I think my number of posts is off by one, is this a problem for anyone else?
Maybe depending on the recency of the post your page is currently on might show one less but you still have that post
- Sun Dec 08, 2019 10:12 pm
- Forum: Administrative Questions and Class Announcements
- Topic: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
- Replies: 115
- Views: 12193
Re: MARSHMALLOW- FINAL REVIEW SESSION [ENDORSED]
For #17 on the marshmallow final, why is the pi bond composition for oxygen is O2p, C2sp2? I thought it only used the p orbital?
- Sun Dec 08, 2019 10:07 pm
- Forum: Student Social/Study Group
- Topic: Class Grading
- Replies: 44
- Views: 3509
Re: Class Grading
Let's hope it gets curved!
- Sun Dec 08, 2019 9:58 pm
- Forum: Student Social/Study Group
- Topic: Cyanide
- Replies: 5
- Views: 483
Cyanide
How do you calculate the formal charges for each atom in CN-?
- Sun Dec 08, 2019 9:57 pm
- Forum: Student Social/Study Group
- Topic: Final
- Replies: 4
- Views: 428
Final
Did anyone know how to do that one question where it asked to draw cyanide and a heme complex and where it attached?
- Sun Dec 01, 2019 11:39 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis acid & Bronstead Acid
- Replies: 3
- Views: 179
Lewis acid & Bronstead Acid
What's the difference between a Lewis acid and a Bronstead acid?
- Sun Dec 01, 2019 11:25 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: electronegativity
- Replies: 4
- Views: 140
electronegativity
How do you know when an atom has higher electronegativity? ex) ClO, BrO, IO
- Sun Dec 01, 2019 11:20 pm
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: Trichloroacetic acid
- Replies: 2
- Views: 97
Trichloroacetic acid
Why is trichloroacetic acid a stronger acid than acetic acid?
- Sun Dec 01, 2019 11:18 pm
- Forum: Acidity & Basicity Constants and The Conjugate Seesaw
- Topic: pka v. ka
- Replies: 4
- Views: 303
pka v. ka
What is the difference between pKA and KA?
- Sun Dec 01, 2019 11:16 pm
- Forum: Lewis Acids & Bases
- Topic: Long bonds vs Short bonds?
- Replies: 9
- Views: 872
Long bonds vs Short bonds?
Why are long bonds weaker than short bonds?
- Sun Nov 24, 2019 9:04 pm
- Forum: Hybridization
- Topic: Shapes
- Replies: 3
- Views: 136
Shapes
How do different shapes contribute to different hybridizations?
- Sun Nov 24, 2019 8:57 pm
- Forum: Hybridization
- Topic: d orbital
- Replies: 4
- Views: 292
d orbital
why is the d orbital written before the s and p orbital when writing the hybridization state?
- Sun Nov 24, 2019 8:52 pm
- Forum: Hybridization
- Topic: C2H4
- Replies: 2
- Views: 166
C2H4
In class when we wrote the hybridization for C2H4, why is it written as 3sp^2 when there's only 2 central atoms?
- Sun Nov 24, 2019 8:09 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Polarity
- Replies: 4
- Views: 180
Polarity
How can you tell when forces within a molecule cancel out?
- Sun Nov 24, 2019 6:18 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: H3O+
- Replies: 12
- Views: 26097
Re: H3O+
sbeall_1C wrote:Hi!
H3O+ has a molecular geometry of tetrahedral, since there are 4 regions of electron density surrounding the central O atom (3 Hydrogens and 1 lone pair of electrons). The VSEPR shape would be trigonal pyramidal.
What does this mean in terms of bond angles?
- Sun Nov 24, 2019 2:06 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: H3O+
- Replies: 12
- Views: 26097
H3O+
Why is H3O+ tetrahedral?
- Sun Nov 17, 2019 11:55 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Repulsion strength
- Replies: 5
- Views: 296
Repulsion strength
Is the repulsion strength stronger when electrons are closer or further apart?
- Sun Nov 17, 2019 11:50 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Additional lone pairs
- Replies: 2
- Views: 210
Additional lone pairs
How do additional lone pairs force bonding electrons closer together?
- Sun Nov 17, 2019 11:48 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: electronegativity
- Replies: 6
- Views: 367
electronegativity
How can you determine high electronegativity in a molecule?
- Sun Nov 17, 2019 11:25 pm
- Forum: Bond Lengths & Energies
- Topic: Test 2 Topics
- Replies: 40
- Views: 2048
Re: Test 2 Topics
Does anyone know what sections of the book/homework problems the test covers?
- Sun Nov 17, 2019 11:22 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: IMF
- Replies: 3
- Views: 140
IMF
How can you tell when a molecule has dipole-dipole vs. ion-dipole forces?
- Sun Nov 10, 2019 7:29 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: molar mass and attractive interactions
- Replies: 3
- Views: 141
molar mass and attractive interactions
Why does the increase in molar mass lead to stronger attractive interactions?
- Sun Nov 10, 2019 7:27 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Interaction Potential Energy
- Replies: 1
- Views: 71
Interaction Potential Energy
What is the difference between the equation for the interaction potential energy equation Ep a -a1a2/r^6 and 1/r^6
- Sun Nov 10, 2019 7:09 pm
- Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
- Topic: interactions
- Replies: 2
- Views: 96
Re: interactions
dipole-induced dipole is a weak attraction that results when a polar molecule induces a dipole in an atom or in a nonpolar molecule by disturbing the arrangement of electrons in the nonpolar species. Dipole-dipole interactions align the molecules to increase the attraction.A dipole is two opposite c...
- Sun Nov 10, 2019 6:58 pm
- Forum: Student Social/Study Group
- Topic: Chemistry Youtube Channels
- Replies: 8
- Views: 431
Re: Chemistry Youtube Channels
The Organic Chemistry Tutor is a helpful channel
- Sun Nov 10, 2019 6:56 pm
- Forum: Hybridization
- Topic: 2F.5
- Replies: 4
- Views: 292
Re: 2F.5
You find the hybridization of an atom by finding its steric number: the number of atoms bonded to the atom + the number of lone pairs the atom has.
- Sun Nov 03, 2019 11:58 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Electron configuration
- Replies: 7
- Views: 451
Electron configuration
Does anyone know the factual reasoning behind why we fill up the 4s orbital before the 3d orbital?
- Sun Nov 03, 2019 11:55 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: n, l ,ml, ms
- Replies: 13
- Views: 1419
n, l ,ml, ms
I am confused on what to write for ms = ... I am not sure if we are supposed to pick -1/2, +1/2 or both or just how we get an answer for it
- Sun Nov 03, 2019 11:51 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic and covalent bonds
- Replies: 2
- Views: 96
Ionic and covalent bonds
What is the difference with ionic and covalent bonds when drawing lewis structures?
- Sun Nov 03, 2019 11:49 pm
- Forum: Lewis Structures
- Topic: formal charge
- Replies: 4
- Views: 136
Re: formal charge
formal charge just keeps track of the electrons and whether they are being given away(+) or gained (-)
- Sun Nov 03, 2019 11:47 pm
- Forum: Lewis Structures
- Topic: Lewis Structures
- Replies: 3
- Views: 217
Lewis Structures
How would I know when it is right to use a double bond or triple bond? For example CO
- Sun Oct 27, 2019 8:25 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: 2A.15
- Replies: 3
- Views: 130
Re: 2A.15
I think it is based off the valence electrons and how many are needed or exceeding the number allowed on each shell
- Sun Oct 27, 2019 7:20 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2A 19
- Replies: 2
- Views: 104
Re: 2A 19
Maybe because it is already more than half full, it more favorable to have a full d-orbital and donate the electrons from the highest shell (4s-shell)
- Sun Oct 27, 2019 6:40 pm
- Forum: Ionic & Covalent Bonds
- Topic: Charges
- Replies: 4
- Views: 214
Re: Charges
An S atom has 6 valence electrons and an O atom has 6 valence electrons so when finding the valence electrons for the SO4 compound, you get 30 electrons. 32 valence electrons are needed for 4 full outer shells but SO4 has 30 electrons. So, the charge is 2-.
- Sun Oct 27, 2019 6:33 pm
- Forum: General Science Questions
- Topic: Midterms
- Replies: 22
- Views: 863
Re: Midterms
Jessica Tejero 3L wrote:Midterms are just the prior info given before the test. I believe the finals are cumulative.
So from fundamentals to whatever topic before the midterm?
- Sun Oct 27, 2019 6:31 pm
- Forum: Ionic & Covalent Bonds
- Topic: 2A 5
- Replies: 2
- Views: 106
Re: 2A 5
It's because a full d- orbital is more energetically favorable than a full s- orbital and since it is a Cu + atom, it is removing one electron from the "highest" shell which in this case would be the 4s- shell.
- Sun Oct 20, 2019 6:43 pm
- Forum: Properties of Light
- Topic: Wien's Law
- Replies: 2
- Views: 94
Wien's Law
When are we supposed to use Wien's law? Is it going to be any problem with temperature associated with max wavelength or is it finding the temperature of particular things?
- Sun Oct 20, 2019 6:38 pm
- Forum: Properties of Light
- Topic: Week 3 Homework
- Replies: 9
- Views: 374
Re: Week 3 Homework
I think you can still turn in quantum homework problems since we technically are still working on them this week (Monday).
- Sun Oct 20, 2019 6:36 pm
- Forum: Student Social/Study Group
- Topic: Lecture on friday
- Replies: 4
- Views: 367
Re: Lecture on friday
We went over multielectron atoms and their potential energies of electrons [(q1)(q2)/r] and we talked about electron configurations and the order in which each orbital fills up and writing their structures [1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, (8s, 5g, 6f, 7d, ...
- Sun Oct 20, 2019 6:16 pm
- Forum: Properties of Light
- Topic: 1B. 5
- Replies: 2
- Views: 94
1B. 5
"The y-ray photons emitted by the nuclear decay of a technetium-99 atom used in radiopharmaceuticals have an energy of 140.511 keV. Calculate the wavelength of the these y-rays."
I'm not sure where to start with this problem.
I'm not sure where to start with this problem.
- Sun Oct 20, 2019 3:59 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electron Configuration
- Replies: 5
- Views: 212
Re: Electron Configuration
The order of electrons that fill up orbitals are written as 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, and so on.
- Tue Oct 08, 2019 11:40 pm
- Forum: Empirical & Molecular Formulas
- Topic: Molecular to Empirical Formula
- Replies: 10
- Views: 917
Molecular to Empirical Formula
Does anyone know how to get the molecular formula being given only the empirical formula?
- Tue Oct 08, 2019 11:36 pm
- Forum: Empirical & Molecular Formulas
- Topic: Formula Units
- Replies: 10
- Views: 364
Re: Formula Units
It's used for conversion to atoms, compounds, and molecules.
- Tue Oct 08, 2019 11:30 pm
- Forum: SI Units, Unit Conversions
- Topic: Problem G.23
- Replies: 3
- Views: 232
Re: Problem G.23
You just find the moles of each compound and add them together and divide the sum by the volume in liters.
- Tue Oct 08, 2019 11:22 pm
- Forum: SI Units, Unit Conversions
- Topic: Will we have to know how to convert from Fahrenheit, Celsius, and Kelvin?
- Replies: 4
- Views: 239
Re: Will we have to know how to convert from Fahrenheit, Celsius, and Kelvin?
The formulas are pretty simple and majority of the time the problems are asking for conversion of fahrenheit to celsius or Kelvin.
- Tue Oct 08, 2019 11:18 pm
- Forum: Trends in The Periodic Table
- Topic: Chemistry Community
- Replies: 4
- Views: 175
Re: Chemistry Community
I believe it's due Sunday night at 11:59 pm.
- Tue Oct 08, 2019 11:17 pm
- Forum: Significant Figures
- Topic: Significant Figures for Test 1
- Replies: 3
- Views: 264
Re: Significant Figures for Test 1
I think you should round early on because that l.2595611317x10^-3 is too large and is closer to 1.30x10^-3.
- Tue Oct 01, 2019 10:45 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: How to do E15
- Replies: 4
- Views: 214
Re: How to do E15
Since you don't know what the metal is in this metal hydroxide, you will have to find that first. You want to subtract the hydroxide from the metal 74.10 - (2x1.008 + 2x15.999)= 39.94g/mol. On the periodic table, that mass is closest to Calcium. So your metal is Calcium! Now you want to add the mola...
- Tue Oct 01, 2019 10:28 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Formula Units
- Replies: 6
- Views: 350
Re: Formula Units
Avogadro's number doesn't really have an assigned unit except for the fact moles can go into it. I think it's useful when you have a value already in moles and you want to convert it to something like atoms or formula units.