Search found 71 matches
- Tue Mar 12, 2019 5:24 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Slow vs Fast Step
- Replies: 4
- Views: 445
Re: Slow vs Fast Step
the slow step usually has the same rate as the observed rate
- Tue Mar 12, 2019 5:24 pm
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Slow or Fast Step
- Replies: 3
- Views: 453
Re: Slow or Fast Step
the reaction rate that matches the experimental rate is the slow step.
- Tue Mar 12, 2019 5:22 pm
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: catalyst and equilibrium constant
- Replies: 2
- Views: 266
catalyst and equilibrium constant
if a catalyst affects the rate constant and rate constants of forward and reverse reactions can be used to find equilibrium constant then why does the catalyst not affect the equilibrium constant?
- Tue Mar 05, 2019 3:54 pm
- Forum: General Rate Laws
- Topic: overall reaction rate
- Replies: 2
- Views: 295
overall reaction rate
what is the overall reaction rate used for?
- Tue Mar 05, 2019 3:52 pm
- Forum: Kinetics vs. Thermodynamics Controlling a Reaction
- Topic: Reaction order
- Replies: 4
- Views: 419
Re: Reaction order
you can find that by adding all the individual reaction orders together
- Tue Mar 05, 2019 3:51 pm
- Forum: General Rate Laws
- Topic: how to calculate reaction rates
- Replies: 2
- Views: 399
how to calculate reaction rates
what are the different ways that we can calculate reaction rates?
- Tue Feb 26, 2019 2:05 pm
- Forum: Balancing Redox Reactions
- Topic: Br2(l)-->Br^-(aq)
- Replies: 1
- Views: 252
Br2(l)-->Br^-(aq)
how can you tell that Br2(l)-->Br^-(aq) is a reduction? what would the oxidation numbers be?
- Tue Feb 26, 2019 2:04 pm
- Forum: Balancing Redox Reactions
- Topic: oxidized vs oxidizing agent
- Replies: 3
- Views: 284
oxidized vs oxidizing agent
what is the difference between oxidized and oxidizing agent?
- Tue Feb 26, 2019 2:04 pm
- Forum: Balancing Redox Reactions
- Topic: balancing basic half reactions
- Replies: 1
- Views: 227
balancing basic half reactions
why do we balance H with H2O in basic rxns instead of just OH to begin with?
- Wed Feb 20, 2019 3:55 pm
- Forum: Van't Hoff Equation
- Topic: when to use
- Replies: 4
- Views: 478
when to use
when do we want to use the Van't Hoff equation?
- Wed Feb 20, 2019 3:54 pm
- Forum: Van't Hoff Equation
- Topic: Non-consistant enthalpy
- Replies: 3
- Views: 415
Re: Non-consistant enthalpy
delta H and delta S should be consistent values to use this equation
- Wed Feb 20, 2019 3:52 pm
- Forum: Balancing Redox Reactions
- Topic: how to balance
- Replies: 5
- Views: 501
how to balance
do you balance redox rxns by oxidation number or stoichiometry?
- Thu Feb 14, 2019 3:28 pm
- Forum: Thermodynamic Systems (Open, Closed, Isolated)
- Topic: Cp,m
- Replies: 5
- Views: 814
Re: Cp,m
Cp is for constant pressure and can be used in solving for q or delta S.
Cv is for constant volume in the same equations
Cv is for constant volume in the same equations
- Mon Feb 11, 2019 3:18 pm
- Forum: Entropy Changes Due to Changes in Volume and Temperature
- Topic: 3/2R and 5/2R
- Replies: 2
- Views: 323
3/2R and 5/2R
do you use 3/2R and 5/2R when calculating change in entropy when there is a temperature change? are there any other situations where you would use them?
- Mon Feb 11, 2019 3:00 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: bond enthalpies
- Replies: 3
- Views: 336
bond enthalpies
do you only use gases when solving with bond enthalpies or can you use solids and liquids as well?
- Thu Feb 07, 2019 12:12 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: ΔH
- Replies: 2
- Views: 303
ΔH
I thought when we calculated for ΔH, the equation used was ΔH=nCΔT, but in some calculations they don't use ΔT. Why is that?
- Wed Feb 06, 2019 8:28 pm
- Forum: Calculating Work of Expansion
- Topic: Isothermal processes
- Replies: 2
- Views: 329
Re: Isothermal processes
isothermal means that the temperature stays the same and I believe that is the right equation to use when solving those types of problems
- Tue Feb 05, 2019 3:00 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 4.15 (7th edition)
- Replies: 2
- Views: 359
4.15 (7th edition)
for 4.15 in the 7th edition book, the balanced chemical equation is 2HCl(aq)+Zn(s)--->H2(g)+ZnCl2(aq) and it tells you that a piece of zinc metal of mass 8.5 g is dropped into an apparatus containing 800.0ml of 0.5M HCl(aq). If the initial temp of the HCl acid solution is 25C, what is the final temp...
- Tue Feb 05, 2019 1:15 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: ΔH and ΔU
- Replies: 6
- Views: 880
ΔH and ΔU
what does the degree symbol mean in the equation ΔU°=ΔH°+W
- Wed Jan 30, 2019 2:08 pm
- Forum: Calculating Work of Expansion
- Topic: Units for Work
- Replies: 6
- Views: 714
Re: Units for Work
Units for work is in Joules and 1J is equal to kg*m^2*s^-2
- Tue Jan 29, 2019 9:59 am
- Forum: Calculating Work of Expansion
- Topic: reversible process
- Replies: 3
- Views: 353
reversible process
is the value for R in the equation w=-nRTln(V2/V1) always the same?
- Tue Jan 29, 2019 9:50 am
- Forum: Calculating Work of Expansion
- Topic: 4A.3 7th Ed
- Replies: 6
- Views: 542
4A.3 7th Ed
how do I figure out how to determine the change in volume when I am solving for work done? the question asks to solve for the work of a pump in compression with a diameter of 3cm and the pump is depressed 20cm with a pressure of 2atm. thank you~
- Thu Jan 24, 2019 11:28 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: pH vs pKa
- Replies: 3
- Views: 375
pH vs pKa
what is the difference between pH and pKa? how would you solve for pKa if given pH?
- Tue Jan 22, 2019 8:45 am
- Forum: Ideal Gases
- Topic: ICE table
- Replies: 5
- Views: 760
ICE table
for gases in ICE table, do we still use concentration (mol/l) or use bar?
- Tue Jan 22, 2019 8:45 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Calculating with Salts
- Replies: 1
- Views: 109
Calculating with Salts
if you're calculating with salts, how do you know what part of the equation you don't need to add in finding out values for K or Q?
- Tue Jan 22, 2019 8:43 am
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Exothermic vs Endothermic
- Replies: 4
- Views: 1128
Exothermic vs Endothermic
I know that you can figure out which way the rxn will favor if you know whether it's endothermic or exothermic, but how can you figure that out?
- Tue Jan 15, 2019 11:12 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 7th edition 6B.3
- Replies: 1
- Views: 127
7th edition 6B.3
I don't understand how to do part (b) of 6B.3 in the 7th edition with the 200ml value and 250ml value
- Tue Jan 15, 2019 11:11 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Calculating Equilibrium values
- Replies: 2
- Views: 275
Calculating Equilibrium values
Do you have to figure out which direction the reaction goes before doing ICE table?
- Tue Jan 15, 2019 11:10 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE charts
- Replies: 3
- Views: 319
ICE charts
In ICE charts can you fill in the chart with different units of measurement? Ex moles, mol/L, grams
- Wed Jan 09, 2019 4:20 pm
- Forum: Ideal Gases
- Topic: use
- Replies: 8
- Views: 267
Re: use
Noh_Jasmine_1G wrote:when do you use this equation?
forgot to write the equation haha. its the partial pressure equation
- Wed Jan 09, 2019 4:19 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: solving for equilibrium constants
- Replies: 3
- Views: 85
solving for equilibrium constants
when solving for the equilibrium constant using gases, can you use either mol/L or in bar?
- Wed Jan 09, 2019 4:18 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: [Cl2] vs (PCl2)
- Replies: 1
- Views: 94
[Cl2] vs (PCl2)
what is the difference between [Cl2] vs (PCl2) and what does the brackets mean compared to the parenthesis with P in them?
- Wed Jan 09, 2019 4:15 pm
- Forum: Ideal Gases
- Topic: use
- Replies: 8
- Views: 267
use
when do you use this equation?
- Tue Dec 04, 2018 8:06 pm
- Forum: Bronsted Acids & Bases
- Topic: Acetic acid vs Formic acid
- Replies: 1
- Views: 363
Acetic acid vs Formic acid
Why is formic acid a stronger acid than acetic acid? Formic acid has a -CH3 group and acetic acid is HCOOH.
- Tue Dec 04, 2018 7:59 pm
- Forum: Naming
- Topic: Writing formulas
- Replies: 2
- Views: 270
Writing formulas
How do you write the chemical formula for coordinations compounds? Are they alphabetical?
- Tue Dec 04, 2018 7:57 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Polydentate
- Replies: 1
- Views: 264
Polydentate
How can you tell if something is polydentate or not? Are you always given a drawing or do you have to figure it out by the chemical formula?
- Sat Dec 01, 2018 6:24 pm
- Forum: Amphoteric Compounds
- Topic: acidic, basic, and amphoteric oxides
- Replies: 2
- Views: 370
acidic, basic, and amphoteric oxides
can someone explain what acidic, basic, and amphoteric oxides are? I didn't understand the book's definition of it
- Mon Nov 26, 2018 4:45 pm
- Forum: Hybridization
- Topic: hybrid orbitals
- Replies: 1
- Views: 151
hybrid orbitals
if a hybrid orbital is created, does that mean there is only one electron per energy level?
- Mon Nov 26, 2018 4:40 pm
- Forum: Hybridization
- Topic: multiple bonds: pi and sigma bonds
- Replies: 1
- Views: 248
multiple bonds: pi and sigma bonds
How do you know if one of the orbitals is hybridized or not?
- Mon Nov 26, 2018 4:33 pm
- Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
- Topic: sigma and pi bonds
- Replies: 4
- Views: 501
Re: sigma and pi bonds
sigma bonds are located on the axis and so they are able to rotate around it, but pi bonds are located above and below the axis and therefore cannot rotate
- Wed Nov 21, 2018 7:42 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Molecular Shape
- Replies: 5
- Views: 478
Molecular Shape
for the names of the different shapes, is the only way to learn them is to memorize the names of the shapes that correspond to the AXE form?
- Wed Nov 21, 2018 7:41 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Organizing atoms around central atom
- Replies: 1
- Views: 131
Organizing atoms around central atom
for SO2Cl2, do the 2 oxygens and 2 chlorines have to be next to each other around the sulfur or can they be directly across from each other?
- Wed Nov 21, 2018 7:40 am
- Forum: Hybridization
- Topic: hybridization with bonds
- Replies: 2
- Views: 252
hybridization with bonds
how can you tell the type of bond (pi or sigma) with knowing the hybridization?
- Wed Nov 14, 2018 1:30 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 3
- Views: 313
Re: Bond Angles
Lone pairs have greater repulsion than bonds and therefore cause the bond angles to be smaller than expected
- Wed Nov 14, 2018 1:25 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Electron density
- Replies: 6
- Views: 652
Electron density
does electron density only refer to the central atom? and is the electron density around the central atom the only one we use to determine molecular shape?
- Wed Nov 14, 2018 8:59 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 4
- Views: 433
Bond Angles
do we just have to memorize the bond angles for different molecular shapes?
- Tue Nov 06, 2018 2:35 pm
- Forum: Ionic & Covalent Bonds
- Topic: Greater Ionic Character? [ENDORSED]
- Replies: 3
- Views: 603
Re: Greater Ionic Character? [ENDORSED]
usually the distance between the 2 atoms will be useful. if they are further apart that means they will have greater ionic character because the electronegativity is greater
- Tue Nov 06, 2018 2:33 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Formal Charge of Oxygen
- Replies: 6
- Views: 1642
Formal Charge of Oxygen
why does oxygen usually have the negative formal charge in a lewis structure compared to carbon?
- Tue Nov 06, 2018 2:31 pm
- Forum: Ionic & Covalent Bonds
- Topic: O vs N [ENDORSED]
- Replies: 4
- Views: 521
O vs N [ENDORSED]
why does Oxygen have lower ionization energy than Nitrogen ?
- Sun Nov 04, 2018 12:41 pm
- Forum: Ionic & Covalent Bonds
- Topic: Be vs Mg
- Replies: 1
- Views: 174
Be vs Mg
why are the electron affinities for Be and Mg the same when Mg is below Be? I thought electron affinity increases as you go right and up
- Wed Oct 31, 2018 9:19 am
- Forum: Electronegativity
- Topic: Periodic Trends [ENDORSED]
- Replies: 3
- Views: 464
Periodic Trends [ENDORSED]
why does electronegativity, electron affinity, and ionization energy all increase to the right?
- Tue Oct 30, 2018 9:52 pm
- Forum: Lewis Structures
- Topic: How to determine central atom
- Replies: 8
- Views: 1493
How to determine central atom
hi, how do I determine the central atom of a lewis structure?
- Tue Oct 30, 2018 9:48 pm
- Forum: Formal Charge and Oxidation Numbers
- Topic: Energy and Stability of an Atom
- Replies: 2
- Views: 347
Energy and Stability of an Atom
why does lower energy mean that an atom is more stable?
- Mon Oct 29, 2018 6:33 pm
- Forum: Lewis Structures
- Topic: Lewis Structure for Compounds
- Replies: 2
- Views: 158
Lewis Structure for Compounds
how do you know to draw two separate lewis structures for ammonium sulfate and just one for glycine (H2O(NH2)COOH)?
- Tue Oct 23, 2018 2:42 pm
- Forum: Einstein Equation
- Topic: λ=h/p vs λ=hc/E
- Replies: 6
- Views: 3817
λ=h/p vs λ=hc/E
Hi, I am confused on when to use the equation λ=h/p vs λ=hc/E or if they are interchangeable. thank you so much !
- Mon Oct 22, 2018 2:23 pm
- Forum: Electron Configurations for Multi-Electron Atoms
- Topic: Electrostatic attraction for multi-electron atoms
- Replies: 1
- Views: 111
Electrostatic attraction for multi-electron atoms
hi, i'm confused on what shielding does to the s, p, d, and f orbitals. I know that p has greater energy than s but is this talking about the electrons energy being closer to zero? also how does all of this relate to the equation: E is proportionate to (q1)(q2)/r ?
- Mon Oct 22, 2018 2:17 pm
- Forum: Properties of Electrons
- Topic: Difference between electron's particle like and wave like characteristics
- Replies: 5
- Views: 387
Difference between electron's particle like and wave like characteristics
Hi, could someone clarify the characteristics that make an electron act like both a particle and wave?
- Mon Oct 22, 2018 2:12 pm
- Forum: *Shrodinger Equation
- Topic: How Schrodinger Equation Relates to Atomic Orbitals
- Replies: 1
- Views: 461
How Schrodinger Equation Relates to Atomic Orbitals
Hi, I am confused on how we make the connection between the Schrodinger Equation and the determination of atomic orbitals. Could someone explain it to me?
- Tue Oct 16, 2018 2:50 pm
- Forum: Einstein Equation
- Topic: Question regarding wavelength
- Replies: 5
- Views: 478
Re: Question regarding wavelength
angelagd3l wrote:what units are we using while working with wavelengths?
wavelengths are usually given in meters but usually you can switch it by a power of 10 to make nanometers, picometers, etc to make the number friendlier
- Tue Oct 16, 2018 2:46 pm
- Forum: Properties of Light
- Topic: E=hv
- Replies: 13
- Views: 1110
Re: E=hv
Tamera Scott 3L wrote:I've also seen E=hf once, does anyone know if that is the same as E=hv?
v is the symbol for frequency, so both equations are equivalent
- Tue Oct 16, 2018 2:44 pm
- Forum: Properties of Light
- Topic: Question 1B.7
- Replies: 2
- Views: 163
Re: Question 1B.7
I'm not completely sure but I think that the energy per atom can be found at the back of the textbook for the referencing during homework and should be given for a test.
- Thu Oct 11, 2018 4:15 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Moles [ENDORSED]
- Replies: 6
- Views: 1273
Re: Moles [ENDORSED]
This is just showing the ratio of the Fe to the compound for that specific chemical reaction. The molar ratio could be different for other reactions
- Thu Oct 11, 2018 4:13 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: molar masses on the test
- Replies: 7
- Views: 936
Re: molar masses on the test
You can solve for the molar mass if the question gives you the chemical formula because there is a periodic table given for the test
- Thu Oct 11, 2018 4:11 pm
- Forum: Balancing Chemical Reactions
- Topic: Where to start [ENDORSED]
- Replies: 10
- Views: 1421
Re: Where to start [ENDORSED]
I usually start with the one that appears the least (usually only once) because then I don't have to search around and make sure I'm adding all the moles correctly. After starting with the least, I see which numbers would be easiest to match and go from there
- Thu Oct 11, 2018 4:07 pm
- Forum: Significant Figures
- Topic: Rounding Using Significant Figures
- Replies: 10
- Views: 1544
Re: Rounding Using Significant Figures
In multiplying and dividing you always use the smallest number of sig figs between those two numbers and in adding and subtracting you should use the smallest number after the decimal point. For example: 1.23 + 1.5 would be 2 sig figs because there is only one number after the decimal point in 1.5
- Thu Oct 04, 2018 4:15 pm
- Forum: Empirical & Molecular Formulas
- Topic: chemical formulas
- Replies: 4
- Views: 2109
chemical formulas
hi, I can confused on when to use subscripts for certain elements on the periodic table. For example, I don't know understand why chlorine gas is written as Cl2 instead of just Cl (M.15)
- Thu Oct 04, 2018 12:58 pm
- Forum: Limiting Reactant Calculations
- Topic: chemical formula regarding M.9
- Replies: 2
- Views: 607
chemical formula regarding M.9
hi, I just had a question for M.9, which asks for us to write the net ionic equation for the reaction: copper(II) nitrate reacts with sodium hydroxide to produce a precipitate of light blue copper(II) hydroxide. what do the Roman numerals mean and how does NaNO3 appear on the products side out of no...
- Wed Oct 03, 2018 5:14 pm
- Forum: Empirical & Molecular Formulas
- Topic: Fundamental L.39
- Replies: 6
- Views: 441
Re: Fundamental L.39
Hi. I have a question regarding this problem as well: why is the oxygen written as "O" without the subscript 2 until the formula is written? I though oxygen was always O2
- Sun Sep 30, 2018 8:51 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Molar Mass of Sulfide
- Replies: 2
- Views: 569
Molar Mass of Sulfide
Hi I have a question on E.15 (7th edition). It gives me the molar mass of a metal oxide M(OH)2 as 74.10 g/mol and asks me to find the molar mass of the sulfide. How do I make the connection between sulfide and (OH)2?
- Sat Sep 29, 2018 8:09 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Equal Masses Between Two Atoms
- Replies: 1
- Views: 154
Re: Equal Masses Between Two Atoms
Update: I realized that the astatine atoms weren't on the pan and figured it out!
- Sat Sep 29, 2018 7:51 pm
- Forum: Accuracy, Precision, Mole, Other Definitions
- Topic: Equal Masses Between Two Atoms
- Replies: 1
- Views: 154
Equal Masses Between Two Atoms
Referring to question E.3, how do you know to increase astatine atoms by 3? It gives you 9 gallium atoms (molar mass 70 g/mol) and 9 astatine atoms (molar mass 210 g/mol) and asks how many astatine atoms are needed to make the masses equal.