Search found 61 matches
- Fri Mar 15, 2019 3:13 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Test 2
- Replies: 5
- Views: 509
Re: Test 2
So can we assume we always assume that when the pH is 7 then it will be pH + pH = 14 in which we will divide by 2.
- Fri Mar 15, 2019 10:11 am
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Test 2
- Replies: 5
- Views: 509
Re: Test 2
How is there 2pH?
- Fri Mar 15, 2019 10:09 am
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Test 2
- Replies: 3
- Views: 421
Re: Test 2
When would ΔG=0?
- Wed Mar 13, 2019 2:15 pm
- Forum: First Order Reactions
- Topic: 7B.9
- Replies: 2
- Views: 367
7B.9
For the first order reaction A \rightarrow 3B + C, When [A]0 = .015 mol/l, the concentration of B increases to .018 mol/ L in 3.0 min. a) What is the rate of constant for the reaction expressed as the rate of loss of A? I got the answer 1.7 minutes but the answer is .17 minutes. I was wondering how ...
- Tue Mar 12, 2019 11:37 pm
- Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
- Topic: Test 2
- Replies: 3
- Views: 421
Test 2
7b. The combustion of a gas used to heat a BBQ at a pool party.
Would this be a spontaneous reaction?
Would this be a spontaneous reaction?
- Tue Mar 12, 2019 11:28 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Test 2
- Replies: 5
- Views: 509
Test 2
5. The ionic dissociation of water is given by the following reaction: The ΔH for the reaction is 58kJ/mol. The Kw for the reaction at 25°C is 10^-14. Is a pH of 7 acidic or basic at 30°C? 2H2O(l) \leftrightarrow H30+(aq) + OH-(aq) What is the pH? I used the nerst equation but I'm not getting the ri...
- Tue Mar 12, 2019 11:23 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Test 2 Cell Diagram
- Replies: 3
- Views: 479
Test 2 Cell Diagram
When do we use a comma for the cell diagram?
Do we also use a conductor when there is no solid present?
Do we also use a conductor when there is no solid present?
- Thu Mar 07, 2019 12:34 am
- Forum: General Rate Laws
- Topic: 7A.15
- Replies: 1
- Views: 233
7A.15
How do you find the order for the reactants and overall order?
I'm confused on when to use each experiment?
I'm confused on when to use each experiment?
- Thu Mar 07, 2019 12:09 am
- Forum: General Rate Laws
- Topic: 7A.13
- Replies: 3
- Views: 471
7A.13
In the reaction CH3Br + OH- CH3OH + Br-, when the OH- concentration alone was doubled, the rate doubled; when the CH3Br concentration alone was increased by a factor of 1.2, the rate increased by a factor of 1.2. Write the rate law for the reaction.
How do you determine the rate law?
How do you determine the rate law?
- Thu Feb 28, 2019 12:19 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L.5
- Replies: 1
- Views: 190
6L.5
Write the half reactions, balanced equation for the cell reaction and the cell diagram.
d) Au^+(aq) Au(s) + Au^3+(aq)
Why do we use the solid Au for the anode?
d) Au^+(aq) Au(s) + Au^3+(aq)
Why do we use the solid Au for the anode?
- Wed Feb 27, 2019 11:33 pm
- Forum: Balancing Redox Reactions
- Topic: 6K.5
- Replies: 2
- Views: 373
Re: 6K.5
Thank you I forgot about the negative charge on OH so I put the electrons on the wrong side.
- Wed Feb 27, 2019 10:29 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: 6L.1
- Replies: 1
- Views: 239
6L.1
When calculating the standard reaction GIbbs free energy how do we find n?
- Wed Feb 27, 2019 8:29 pm
- Forum: Balancing Redox Reactions
- Topic: 6K.5
- Replies: 2
- Views: 373
6K.5
Balance each of the following skeletal equations by using oxidation and reduction half reactions.
a) O3 + Br- O2 + BrO3-
How do you balance the half reaction of O3 O2?
a) O3 + Br- O2 + BrO3-
How do you balance the half reaction of O3 O2?
- Wed Feb 27, 2019 6:43 pm
- Forum: Balancing Redox Reactions
- Topic: 6K.3
- Replies: 1
- Views: 224
6K.3
Balance each of the following skeletal equations by using oxidation and reduction half reactions.
d) Cl2 HClO + Cl2
d) Cl2 HClO + Cl2
- Tue Feb 26, 2019 10:33 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Midterm
- Replies: 5
- Views: 529
Midterm
What does it mean for part 1c to comment on the relative stability of the reactants and products?
- Mon Feb 11, 2019 12:38 am
- 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: 4G. 2B 7th edition
- Replies: 2
- Views: 380
4G. 2B 7th edition
Suggest a reason why the entropy of ice is nonzero at T= 0; think about how the structure of ice is affected by the hydrogen bonds.
- Mon Feb 11, 2019 12:13 am
- 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: 4G. 1B 7th edition
- Replies: 1
- Views: 254
4G. 1B 7th edition
Calculate the entropy of a sample of a solid in which it is supposed that a substituted benzene molecule, C6H5F, may be found in any one of six orientations with the same energy at T=0. Suppose there is 1.0 mol of molecules in the sample.
Why is one mole of the molecule multiplied with the equation?
Why is one mole of the molecule multiplied with the equation?
- Mon Feb 11, 2019 12:02 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Bond enthalpies
- Replies: 10
- Views: 870
Bond enthalpies
To solve for bond enthalpies, do we have to know the lewis structure of the molecules?
- Wed Feb 06, 2019 11:35 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: 7th edition 4F.9
- Replies: 1
- Views: 239
7th edition 4F.9
Calculate the change in entropy when the pressure of 1.5mol Ne(g) is decreased isothermally from 15.0 atm to .500 atm. Assume ideal behavior.
- Wed Jan 30, 2019 8:18 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: 4B.3
- Replies: 1
- Views: 335
4B.3
The internal energy of a system increased by 982 J when it was supplied with 492 J of energy as heat.
How much work was done?
I got that work done was 490J but the book answer is 9.0 x 10^2J.
How much work was done?
I got that work done was 490J but the book answer is 9.0 x 10^2J.
- Wed Jan 30, 2019 6:54 pm
- Forum: Calculating Work of Expansion
- Topic: 4A.3 7th edition
- Replies: 2
- Views: 278
4A.3 7th edition
Air in a bicycle pump is compressed by pushing in the handle. The inner diameter of the pump is 3.0 cm and the pump is depressed 20.cm with a pressure of 2.00 atm.
How do you calculate the change in internal energy?
How do you calculate the change in internal energy?
- Wed Jan 30, 2019 6:46 pm
- Forum: Calculating Work of Expansion
- Topic: 4A.3 7th Ed
- Replies: 6
- Views: 519
Re: 4A.3 7th Ed
Why is it -πr^2?
- Mon Jan 21, 2019 5:49 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Post Assessment
- Replies: 1
- Views: 209
Post Assessment
Determine the shift in equilibrium, if any, which will occur for the following reactions when the temperature is increased a) Photosynthesis: 6 CO2 (g) + 6 H2O (l) ⇌ C6H12O6(s) + 6 O2 (g) delta H° = +2802 kJ.mol-1 b) The hydrolysis of ATP: ATP (aq) + H2O (l) ⇌ ADP + PO42-(aq) delta H° = -30 kJ.mol-1...
- Sun Jan 20, 2019 7:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Post Assessment
- Replies: 1
- Views: 222
Post Assessment
A researcher fills a 1.00 L reaction vessel with 1.84 x 10-4 mol of BrCl gas and heats it to 500 K. At equilibrium, only 18.3 % of the BrCl gas remains. Calculate the equilibrium constant, assuming the following reaction is taking place. 2BrCl(g) ⇌ Br2 (g) + Cl2(g) I keep getting 19.8 but I know tha...
- Wed Jan 16, 2019 8:34 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: 7th Edition 5J.1
- Replies: 3
- Views: 241
7th Edition 5J.1
CO + H2O ⇌ CO2 +H2
c) If the concentration of CO is increased, what happens to the concentration of H2?
Why would H2 increase?
c) If the concentration of CO is increased, what happens to the concentration of H2?
Why would H2 increase?
- Wed Jan 16, 2019 8:28 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: 5I.7 7th edition
- Replies: 2
- Views: 241
Re: 5I.7 7th edition
Thanks, I did forget to convert.
- Wed Jan 16, 2019 7:34 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: 5I.7 7th edition
- Replies: 2
- Views: 241
5I.7 7th edition
A reaction vessel of volume .500L at 700. K contains 1.20 mmol SO2, .50 mmol O2, and .10 mmol SO3. At 700 K, Kc= 1.7 x 10^6 for the equilibrium 2SO2 + O2⇌ 2SO3.
Calculate the reaction quotient Qc.
I got 6.9 x 10^-3 but the answer was 6.9.
Calculate the reaction quotient Qc.
I got 6.9 x 10^-3 but the answer was 6.9.
- Wed Jan 16, 2019 12:55 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: 5I.7 7th edition
- Replies: 1
- Views: 230
5I.7 7th edition
If Q=1.0 for the reactin N2 + O2 2NO at 25 C will the reaction have a tendency to form products or reactants, or will it be at equilibrium?
How to you find the K value of the equation?
How to you find the K value of the equation?
- Wed Jan 16, 2019 12:28 am
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Post Assessment
- Replies: 1
- Views: 135
Post Assessment
Write the equilibrium constant expression for the unbalanced chemical equation.
NO2 (g) + H2 (g) ⇌ NH3 (g) + H2 O (l).
Is the answer (NH3)^2/ (H2)^9(NO3)^2?
NO2 (g) + H2 (g) ⇌ NH3 (g) + H2 O (l).
Is the answer (NH3)^2/ (H2)^9(NO3)^2?
- Thu Jan 10, 2019 4:33 pm
- Forum: Ideal Gases
- Topic: HW # 5G.5 7th edition
- Replies: 2
- Views: 190
HW # 5G.5 7th edition
c) Assuming that the initial pressure of X2 was .10 bar, calculate the value of K for the decomposition.
- Thu Jan 10, 2019 1:01 am
- Forum: Ideal Gases
- Topic: Post Assessment
- Replies: 3
- Views: 225
Post Assessment
Why are equilibrium constants useful?
- Thu Dec 06, 2018 8:01 pm
- Forum: Calculating the pH of Salt Solutions
- Topic: 6D.11
- Replies: 1
- Views: 393
6D.11
Decide whether an aqueous solution of each of the following salts has a pH equal to , greater than, or less than 7? If pH> 7 or pH< 7, write a chemical equation to justify your answer. f) Cu(NO3)2 I don't understand how f) is less than 7. Also how would you write the chemical equation to justify?
- Mon Dec 03, 2018 4:57 pm
- Forum: Naming
- Topic: 9C.3 7th edition
- Replies: 1
- Views: 172
9C.3 7th edition
a)potassium hexacynidochromate (III) - the answer is K3 [Cr(CN)6] How come the formulas don't have a charge when writing from the coordination compounds and why is it K3? d)soduim bisoxaltodiaquaferrate(III) - Na[Fe(OH2)2(CO3)2] Does the order of the ligands matter because I mixed up the (CO3)2 and ...
- Sun Dec 02, 2018 6:31 pm
- Forum: Naming
- Topic: Naming and Charges
- Replies: 1
- Views: 213
Naming and Charges
In lecture, there was an example of [Ni(CN)6]-2 and the name was tetracynonicelate(II). I was confused on the -ate part because I know you add the -ate if the metal has a negative charge but I thought Ni would have a positive charge.
- Thu Nov 29, 2018 10:13 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Charges
- Replies: 4
- Views: 503
Charges
How do you find the charges of each of the elements with the complexes?
- Thu Nov 29, 2018 9:48 pm
- Forum: Naming
- Topic: Coordination Number
- Replies: 3
- Views: 395
Coordination Number
How do you find out the coordination number?
- Mon Nov 26, 2018 11:05 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: Ion- Ion and Dipole- Dipole
- Replies: 1
- Views: 199
Ion- Ion and Dipole- Dipole
How do you tell if molecules have an ion- ion force or a dipole- dipole force? Like I don't understand why HCl is dipole- dipole.
- Mon Nov 26, 2018 7:32 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: Boiling Point
- Replies: 3
- Views: 1878
Boiling Point
Rank the following in terms of increasing boiling point:
LiCl, C3H7OH, C4H8, N2
Does boiling point depend on the strength of the intermolecular force?
LiCl, C3H7OH, C4H8, N2
Does boiling point depend on the strength of the intermolecular force?
- Mon Nov 26, 2018 7:16 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: intermolecular forces
- Replies: 1
- Views: 187
intermolecular forces
Are ion- ion forces stronger than ion- dipole forces?
- Sun Nov 25, 2018 11:13 pm
- Forum: Polarisability of Anions, The Polarizing Power of Cations
- Topic: Polarizability
- Replies: 3
- Views: 533
Polarizability
Which one has higher polarizability?
a) Be 2+ or Li 1+
b) Mg 2+ or Be 2+
I tried using the ideas of the polarizability trend but it didn't work.
a) Be 2+ or Li 1+
b) Mg 2+ or Be 2+
I tried using the ideas of the polarizability trend but it didn't work.
- Sat Nov 24, 2018 10:32 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E. 18
- Replies: 1
- Views: 211
2E. 18
d) Draw the lewis structure, VESPR formula, molecular shape, and bond angles: N2O
Why doesn't the lewis structure for N2O have a lone pair?
Why doesn't the lewis structure for N2O have a lone pair?
- Sat Nov 24, 2018 9:16 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: 2E.9
- Replies: 1
- Views: 101
2E.9
What value is expected for the ClICl bond angle?
- Sat Nov 24, 2018 7:51 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: molecular shape vs molecular geometry
- Replies: 3
- Views: 274
molecular shape vs molecular geometry
What is the difference between molecular shape and geometry? Which one depends on lone pairs?
- Mon Nov 12, 2018 7:30 pm
- Forum: Ionic & Covalent Bonds
- Topic: Ionic Compounds 2D3
- Replies: 2
- Views: 470
Ionic Compounds 2D3
How do you determine which compounds have ionic bonds?
And why is BaBr2 primarily more ionic than BeBr2 and BBr3?
And why is BaBr2 primarily more ionic than BeBr2 and BBr3?
- Mon Nov 12, 2018 2:53 am
- Forum: Ionic & Covalent Bonds
- Topic: Boiling Point
- Replies: 3
- Views: 2948
Boiling Point
How do you determine which compounds have a higher boiling point such as CHCl3 and CCl4?
- Sun Nov 04, 2018 5:28 pm
- Forum: Trends in The Periodic Table
- Topic: Electron Affinity
- Replies: 2
- Views: 239
Electron Affinity
Which has a higher electron affinity, chlorine (Cl) or Neon (Ne)?
I know that chlorine has the higher electron affinity but why?
I know that chlorine has the higher electron affinity but why?
- Sun Nov 04, 2018 5:08 pm
- Forum: Trends in The Periodic Table
- Topic: Atomic Radius
- Replies: 4
- Views: 401
Atomic Radius
What is the effect of electrons on the size of the atom?
- Fri Nov 02, 2018 5:22 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Test #2
- Replies: 1
- Views: 236
Test #2
What type of orbital with principal quantum number 4 has one more nodal plan than the 4s orbital?
- Fri Nov 02, 2018 4:42 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Determining electrons
- Replies: 3
- Views: 542
Determining electrons
How do you find the possible number of electrons given by quantum numbers?
Ex: n=2, l= 1
n=4, l=0, ml=-2, ms= -1/2
Ex: n=2, l= 1
n=4, l=0, ml=-2, ms= -1/2
- Fri Oct 26, 2018 5:53 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Test #2
- Replies: 2
- Views: 318
Test #2
When writing the quantum numbers for an orbital, do you include all the values of m?
- Fri Oct 26, 2018 5:36 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: Test #2
- Replies: 3
- Views: 398
Test #2
What does degeneracy mean?
- Mon Oct 22, 2018 10:10 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: post assessment
- Replies: 1
- Views: 176
post assessment
In the hydrogen atomic spectrum, what is the wavelength of light associated with the n = 2 to n = 1 electron transition?
When I worked this problem out, I got -1.22 x 10^-7 as the answer but this isn't correct.
When I worked this problem out, I got -1.22 x 10^-7 as the answer but this isn't correct.
- Thu Oct 18, 2018 7:08 pm
- Forum: DeBroglie Equation
- Topic: post assessment #29
- Replies: 2
- Views: 272
post assessment #29
If a proton and an electron have the same de Broglie wavelength do they have the same speed?
- Sun Oct 14, 2018 6:29 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: post assessment #40
- Replies: 2
- Views: 107
post assessment #40
What is the wavelength of radiation emitted by a hydrogen atom in a transition from the n = 6 to the n = 5 energy level?
- Sun Oct 14, 2018 4:29 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: post assessment #28
- Replies: 1
- Views: 158
post assessment #28
The meter was defined in 1963 as 1,650,763.73 wavelengths of radiation emitted by krypton-86 (it has since been redefined). What is the wavelength of this krypton-86 radiation? To what region of the electromagnetic spectrum does this wavelength correspond (i.e. infrared, ultraviolet, x-ray, etc.)? W...
- Sat Oct 13, 2018 6:01 pm
- Forum: Photoelectric Effect
- Topic: Module Question 28 Part A
- Replies: 1
- Views: 154
Re: Module Question 28 Part A
I used the equation Ek= 1/2mv^2 for this problem. The problem already gives you the velocity and the mass of the electron is 9.109 x 10^-31 kg (which is a constant provided in the back of the textbook). I got 1.98 x 10^-19 J as the answer.
- Tue Oct 09, 2018 6:32 pm
- Forum: Photoelectric Effect
- Topic: post assessment
- Replies: 2
- Views: 218
post assessment
In a photoelectric experiment light hits a metal surface and if the energy of the ________ light is ________ enough it causes electrons to be ejected from the metal surface. A. outgoing, large B. outgoing, small C. incoming, large D. incoming, small E. None of the above I know that the first blank i...
- Sat Oct 06, 2018 1:49 am
- Forum: Molarity, Solutions, Dilutions
- Topic: post assessment
- Replies: 1
- Views: 147
post assessment
5.00 g of KMnO4 is dissolved in a 150.00 mL flask of water. If 20.00 mL of this solution is removed and placed in a new 2nd 250.00 mL flask and filled with water, what is the concentration of the solution in the 2nd flask? Molar Masses: K (39.10 g/mol), Mn (54.94 g/mol), O (16.00 g/mol) Why do you u...
- Sat Oct 06, 2018 1:00 am
- Forum: Molarity, Solutions, Dilutions
- Topic: post assessment
- Replies: 1
- Views: 166
post assessment
What volume of 0.0380 M KMnO4 is needed to prepare 250 mL of 1.50 x 10-3 M KMnO4?
Would you just need to set them equal to each other?
Would you just need to set them equal to each other?
- Thu Oct 04, 2018 5:30 pm
- Forum: Limiting Reactant Calculations
- Topic: Post Assessment 26 [ENDORSED]
- Replies: 1
- Views: 435
Post Assessment 26 [ENDORSED]
Based on the molar ratios in a balanced chemical equation a student expects 0.20 moles of product. If the molar mass of the product is 81 g.mol-1 what is the theoretical yield?
Do I just multiply the expected moles with the actual product? And why?
Do I just multiply the expected moles with the actual product? And why?
- Thu Oct 04, 2018 3:45 pm
- Forum: Empirical & Molecular Formulas
- Topic: Problem F.1b
- Replies: 3
- Views: 394
Problem F.1b
My calculations for the answer were off by the hundredth decimal point. For example I calculated 78.96% when the answer is 78.90%. Would I get the answer wrong?