Search found 73 matches
- Thu Mar 15, 2018 3:25 pm
- Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
- Topic: Figure 9.18 on page 343 [ENDORSED]
- Replies: 1
- Views: 381
Figure 9.18 on page 343 [ENDORSED]
On pg 343, for figure 9.18 (a), why is it that when heat leaves the system, the entropy of the system increases?
- Wed Mar 14, 2018 12:20 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 8.73 b and 8.75 c
- Replies: 1
- Views: 279
8.73 b and 8.75 c
For 8.73 b, you break 4 mol of c-H bonds from CH4. However, in 8.75 c, you break 1 mol C-H bonds from CH4. Im really confused why this is.
- Wed Mar 14, 2018 12:18 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: 8.75
- Replies: 2
- Views: 400
8.75
For b, how do you know that you break c=c bonds and not something like c-h bonds? Also how do you know that you're forming 1 mol c-c bonds, 1 mol c-o bonds and 1 mol of c-H bonds? Im confused as to determining which bonds are broken/formed
- Sat Mar 10, 2018 11:14 am
- Forum: *Enzyme Kinetics
- Topic: Chapter 15 [ENDORSED]
- Replies: 3
- Views: 589
Chapter 15 [ENDORSED]
For chapter 15, are we responsible for 15.1-15.15 (omitting 15.9 of course)??
- Thu Mar 08, 2018 12:05 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Intermediate [ENDORSED]
- Replies: 7
- Views: 873
Intermediate [ENDORSED]
How do you determine the intermediate?
- Thu Mar 08, 2018 12:04 am
- Forum: Reaction Mechanisms, Reaction Profiles
- Topic: Slow step
- Replies: 3
- Views: 395
Slow step
How do you determine the slow step?
- Thu Mar 08, 2018 12:04 am
- Forum: Arrhenius Equation, Activation Energies, Catalysts
- Topic: Arrhenius Equation [ENDORSED]
- Replies: 7
- Views: 832
Arrhenius Equation [ENDORSED]
When do you use the Arrhenius Equation?
- Fri Mar 02, 2018 7:07 pm
- Forum: First Order Reactions
- Topic: Integrated Rate Laws [ENDORSED]
- Replies: 1
- Views: 300
Integrated Rate Laws [ENDORSED]
How do we relate -d[A]/dt with k[A]? Basically, why are they equal to each other? And what's the difference between integrated rate laws and just rate laws in general?
- Fri Mar 02, 2018 7:06 pm
- Forum: First Order Reactions
- Topic: First Order Reactions [ENDORSED]
- Replies: 2
- Views: 3982
First Order Reactions [ENDORSED]
When a reaction is first order, does it mean that it's faster or slower than a second order reaction?
- Fri Mar 02, 2018 7:04 pm
- Forum: Method of Initial Rates (To Determine n and k)
- Topic: Rate Constant [ENDORSED]
- Replies: 3
- Views: 611
Rate Constant [ENDORSED]
What exactly is the rate constant? What does K tell us?
- Wed Feb 21, 2018 12:16 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Electroplating
- Replies: 2
- Views: 414
Electroplating
To what extend do we need to know electroplating?
- Tue Feb 20, 2018 1:13 am
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Ion-selective electrode
- Replies: 2
- Views: 464
Ion-selective electrode
I'm still confused about the function of the ion-selective electrode? what does it do, exactly?
- Tue Feb 20, 2018 1:12 am
- Forum: Balancing Redox Reactions
- Topic: Finding half reactions
- Replies: 4
- Views: 564
Finding half reactions
In example 14.8 on pg. 586, how do you find the two reduction half reactions? is it already given to us?
- Tue Feb 20, 2018 1:11 am
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Standard Hydrogen Electrode
- Replies: 1
- Views: 197
Standard Hydrogen Electrode
I'm still don't quite understand the use of the standard hydrogen electrode? what is it used for exactly?
- Tue Feb 13, 2018 9:54 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Ex 9.10 pg. 342
- Replies: 1
- Views: 287
Ex 9.10 pg. 342
For the problem, it gives us the enthalpy of fusion as 2.292 kJ/mol. Is this a typo? Shouldn't this be the enthalpy of freezing?
- Tue Feb 13, 2018 9:04 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Trouton's rule
- Replies: 1
- Views: 321
Trouton's rule
Do we need to know Trouton's rule for the midterm? It's in the book on pg. 327
- Tue Feb 13, 2018 7:07 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: S=klnW
- Replies: 7
- Views: 3443
S=klnW
In general, in what instance will we be required to use this equation?? like in what context?
- Mon Feb 12, 2018 1:27 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Test #1 Question 1B
- Replies: 3
- Views: 482
Re: Test #1 Question 1B
Where did you get the CL-CL bonds from? They aren't even in the reaction.
- Mon Feb 12, 2018 1:15 am
- Forum: Phase Changes & Related Calculations
- Topic: Test #1 Question 7
- Replies: 1
- Views: 252
Test #1 Question 7
What was the correct answer for question 7 on our first test?
- Mon Feb 12, 2018 1:07 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Test #1 Question 6
- Replies: 2
- Views: 322
Test #1 Question 6
How do you approach this problem? We are given 3 C (graphite), yet it tells us that 4 moles of C (graphite) is reacted. So how do we do this problem?
- Mon Feb 12, 2018 1:01 am
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Test #1 Question 1B
- Replies: 3
- Views: 482
Test #1 Question 1B
Which bond types do we use for bonds broken and which ones do we use for bonds formed for question 1B in our first test?
For bonds broken, I put that we use C=C, C-C, and H-H bonds
For bonds formed, I put that we use C-C and 2 C-H bonds
Is this correct?
For bonds broken, I put that we use C=C, C-C, and H-H bonds
For bonds formed, I put that we use C-C and 2 C-H bonds
Is this correct?
- Thu Feb 08, 2018 11:57 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: "Molar Convention"
- Replies: 2
- Views: 460
"Molar Convention"
So when do we use delta G vs. delta G sub r?
- Thu Feb 08, 2018 11:56 am
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Exothermic/Endothermic
- Replies: 2
- Views: 357
Exothermic/Endothermic
How come for an exothermic reaction, the formation of products is favored by lowering the temperature. Also, why are the products favored by an increase in temperature for an endothermic reaction?
- Thu Feb 08, 2018 11:55 am
- Forum: Van't Hoff Equation
- Topic: van't Hoff Equation
- Replies: 2
- Views: 557
van't Hoff Equation
How do we know whether we're calculating K1 or k2? Also, when do we even use the van't Hoff Equation in the first place?
- Sat Feb 03, 2018 10:17 pm
- Forum: Gibbs Free Energy Concepts and Calculations
- Topic: Delta S, H, and G
- Replies: 2
- Views: 207
Delta S, H, and G
In the solutions manual, I keep on seeing delta S sub r, delta G sub r, and delta H sub r for answers to questions 55 and 57. What does the r stand for? Reactants?
- Thu Feb 01, 2018 11:48 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Bulk Matter
- Replies: 1
- Views: 289
Bulk Matter
What exactly is bulk matter?
- Thu Feb 01, 2018 12:55 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Reversible vs Irreversible
- Replies: 1
- Views: 231
Reversible vs Irreversible
What roles do reversible/irreversible reactions play in relation to change in entropy of a system?
- Thu Feb 01, 2018 12:53 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy: Units and Justification
- Replies: 1
- Views: 202
Re: Entropy: Units and Justification
Entropy is essentially the disorder of a system resulting from the reversible transfer of heat over the absolute temperature of the system (q/T). q is in Joules and T is in K. Thus, q/T is Joules/kelvin.
- Thu Feb 01, 2018 12:02 am
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Question 9.1 part a
- Replies: 1
- Views: 162
Question 9.1 part a
Can someone explain how to start this problem?
- Thu Jan 25, 2018 12:18 am
- Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
- Topic: Heat capacity at constant pressure vs at constant volume [ENDORSED]
- Replies: 1
- Views: 244
Heat capacity at constant pressure vs at constant volume [ENDORSED]
Why is heat capacity at constant pressure greater than that at constant volume?
- Thu Jan 25, 2018 12:04 am
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Translation/Rotational/Vibrational Energy [ENDORSED]
- Replies: 1
- Views: 284
Translation/Rotational/Vibrational Energy [ENDORSED]
Do we need to know translational/rotational/vibrational energy for the test? Also, do we need to know their subsequent equations derived from the equipartition theorem?
- Wed Jan 24, 2018 11:16 pm
- Forum: Calculating Work of Expansion
- Topic: Irreversible expansion
- Replies: 4
- Views: 399
Irreversible expansion
I understand that in an irreversible expansion, the system is not in equilibrium. But what does this conceptually mean? And why is it irreversible?
- Wed Jan 24, 2018 10:51 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Internal Energy
- Replies: 5
- Views: 491
Internal Energy
If delta P = 0 (constant pressure), why is delta U = q + w? I thought that w = -PdeltaV. If P is 0, there would be no work then right?
- Wed Jan 24, 2018 7:25 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Adding reactions
- Replies: 2
- Views: 399
Adding reactions
How come when you add N2 + 02 -> 2 NO with 2 NO + O2 -> 2NO2 you get N2 + 2O2 -> 2NO2? Is it because the 2 NO from the first reaction cancels out the 2 NO from the second reaction?
- Thu Jan 18, 2018 11:05 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Enthalpy [ENDORSED]
- Replies: 3
- Views: 265
Enthalpy [ENDORSED]
What exactly is enthalpy? I need a conceptual explanation. What does negative/positive enthalpy tell us about a reaction?
- Thu Jan 18, 2018 10:06 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Q 8.67
- Replies: 1
- Views: 155
Q 8.67
How do we approach this problem? Especially for a, what are the steps for estimating the enthalpy of formation of H20? Where do we start?
- Thu Jan 18, 2018 9:56 pm
- Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
- Topic: Q. 8.65
- Replies: 2
- Views: 146
Q. 8.65
Can someone explain how to approach this problem without being given an initial reaction? Are we supposed to find the initial reaction ourselves?
- Mon Jan 15, 2018 6:22 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Q. 8.39
- Replies: 2
- Views: 287
Q. 8.39
How much heat is need to convert 80.0 g of ice 0.0 degrees C into liquid water at 20.0 degrees C?
Can someone give a conceptual explanation as well as the steps on approaching this problem?
Can someone give a conceptual explanation as well as the steps on approaching this problem?
- Sat Jan 13, 2018 11:19 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Constant pressure vs. Constant volume
- Replies: 1
- Views: 283
Constant pressure vs. Constant volume
Why is the heat capacity at constant pressure greater than heat capacity at constant volume?
- Sat Jan 13, 2018 11:17 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Heat Capacity
- Replies: 1
- Views: 308
Heat Capacity
For heat capacity at constant volume, why do we use delta U? Similarly, for heat capacity at constant pressure, why do we use delta H?
- Sat Jan 13, 2018 11:11 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Enthalpy and Internal Energy
- Replies: 2
- Views: 228
Enthalpy and Internal Energy
What's the relationship between Enthalpy and Internal Energy? In other words, how do you relate the two? I just need a conceptual explanation.
- Sun Dec 10, 2017 10:54 am
- Forum: Properties & Structures of Inorganic & Organic Acids
- Topic: carboxylic strength
- Replies: 2
- Views: 465
Re: carboxylic strength
For carboxylic acids, the group that is attached to the carboxyl group that is more electronegative causes the carboxylic acid to be more acidic.
- Sat Dec 09, 2017 8:55 pm
- Forum: Lewis Acids & Bases
- Topic: Lewis acids and bases
- Replies: 2
- Views: 351
Lewis acids and bases
To what extent (for the final) do we have to know Lewis acids and bases other than the fact that Lewis acids accept electrons and Lewis bases donate electrons?
- Sat Dec 09, 2017 8:39 pm
- Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
- Topic: Assuming solution is neutral [ENDORSED]
- Replies: 1
- Views: 255
Assuming solution is neutral [ENDORSED]
I understand that if [H30] is less than 10^-7, the solution is considered neutral. But if [OH] is greater than 10^-7, does that mean that we also assume the solution is neutral?
- Wed Nov 29, 2017 8:14 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Making the "Assumption" when calculating equilibrium
- Replies: 1
- Views: 400
Making the "Assumption" when calculating equilibrium
So, I know that you assume x to be negligible when it's less than 5% of initial value. But what is the initial value? Is the initial value the initial concentration of the product/reactant? And how would you know x is less than 5% of initial value if you don't even know what x is?
17.33 (a)
Can someone help me with this problem? How would you tell if HN(CH2CH2NH2)2 is polydentate or not? and if it is, how would you be able to give the maximum number of places the ligand can bind to simultaneously to a single metal center?
- Tue Nov 28, 2017 9:38 pm
- Forum: Naming
- Topic: Polydentate
- Replies: 3
- Views: 585
Polydentate
How do you tell if something is polydentate vs. monodentate?
- Tue Nov 28, 2017 4:53 pm
- Forum: Shape, Structure, Coordination Number, Ligands
- Topic: Coordination compounds and complexes
- Replies: 2
- Views: 257
Coordination compounds and complexes
Can someone briefly explain what coordination compounds and complexes are? Also, what does the coordination sphere tell us?
- Mon Nov 20, 2017 9:55 pm
- Forum: Naming
- Topic: Toolbox 17.1 from Chemistry Textbook
- Replies: 2
- Views: 314
Toolbox 17.1 from Chemistry Textbook
This toolbox breaks naming coordination compounds into 2 procedures. Procedure A is called "Writing the formula" and procedure B is called "Naming the complex". Do we need to know how to do procedure A and B or just procedure B??
- Mon Nov 20, 2017 4:12 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Bond Angles
- Replies: 2
- Views: 244
Bond Angles
Do we have to know the bond angles for every single Lewis structure or just the easy ones like how Linear is 180 degrees?
- Mon Nov 20, 2017 3:57 pm
- Forum: Properties of Electrons
- Topic: Chem Midterm Question Q3C
- Replies: 1
- Views: 339
Chem Midterm Question Q3C
The computing performance of their supercomputer is only related to the speed of the electron. If more high-energy photons are caught from outer space, would the performance be better?
Why is the answer no?
Why is the answer no?
- Sun Nov 19, 2017 5:57 pm
- Forum: Determining Molecular Shape (VSEPR)
- Topic: Si02 VSEPR
- Replies: 2
- Views: 8059
Si02 VSEPR
What is the VSEPR shape of Si02? Also, is it polar or non-polar and how do you tell?
- Sun Nov 19, 2017 5:54 pm
- Forum: Hybridization
- Topic: Hybridization in General
- Replies: 3
- Views: 1849
Hybridization in General
Can someone explain to me the general concept of Hybridization? I'm still not fully understanding the concept and how to apply it to different orbitals.
- Thu Nov 09, 2017 2:45 am
- Forum: Trends in The Periodic Table
- Topic: s-block vs p-block
- Replies: 5
- Views: 3175
Re: s-block vs p-block
s-block metals have lower ionization energies compared to p-block metals. Thus, due to their low ionization energies, s-block metals tend to form cations since they are more willing to give electrons away. Due to this, they are more reactive.
- Tue Nov 07, 2017 3:42 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Post Assessment Module #42
- Replies: 1
- Views: 270
Post Assessment Module #42
#42: An excited hydrogen atom emits light with a frequency of 1.14 x 10^14 Hz to reach the energy level n = 4. In what principle quantum level did the electron begin?
A. n = 5
B. n = 6
C. n = 4
D. n = 7
How do you do this problem (step by step)??
A. n = 5
B. n = 6
C. n = 4
D. n = 7
How do you do this problem (step by step)??
- Wed Nov 01, 2017 10:53 pm
- Forum: Trends in The Periodic Table
- Topic: Problem 2.67 from textbook
- Replies: 2
- Views: 255
Problem 2.67 from textbook
Which element of each of the following pairs has the higher electron affinity?
Nitrogen or Carbon
Why is the answer Carbon? I thought that as you go down a period, the electron affinity gets higher.
Nitrogen or Carbon
Why is the answer Carbon? I thought that as you go down a period, the electron affinity gets higher.
- Wed Nov 01, 2017 2:50 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Post- Module #18 and #23
- Replies: 1
- Views: 278
Re: Post- Module #18 and #23
#18: The delta X is uncertainty in position. It tells us that the uncertainty in position is 1% of .05 nm or .05 x 10^-9 m. So just do 1% of .05 x 10^-9 m and whatever answer you get is your delta X. #23: The delta X in this problem is 10 m since we have to account for everything in between +5 and -5.
- Wed Oct 25, 2017 10:38 pm
- Forum: Trends in The Periodic Table
- Topic: f-orbitals
- Replies: 6
- Views: 6644
Re: f-orbitals
Keep in mind that the f-orbitals (Lanthanides and Actinides) are on the bottom of the periodic table since there are so many that it can't find on the periodic table. So, starting element 57, look at the bottom of the periodic table (Lanthanides and Actinides -> f-orbitals) and start counting from t...
- Wed Oct 25, 2017 8:23 pm
- Forum: Trends in The Periodic Table
- Topic: Isoelectronic ions
- Replies: 2
- Views: 3066
Isoelectronic ions
For the isoelectronic ions Na+, F-, and Mg2+, why is it that Mg2+ has the largest nuclear charge of the 3 (it has the strongest attrition for the electrons and therefore the smallest radius of the 3)?? I thought that as we go down a group, there is shielding which causes electrons to be further from...
- Sat Oct 21, 2017 9:01 pm
- Forum: Quantum Numbers and The H-Atom
- Topic: The 4 Quantum Numbers [ENDORSED]
- Replies: 5
- Views: 3164
The 4 Quantum Numbers [ENDORSED]
Can someone briefly go over the 4 quantum numbers? (n, l, m subscript l, and m subscript s)?
Im stuck specifically with l and m subscript l. What do they mean and what do they show?
Im stuck specifically with l and m subscript l. What do they mean and what do they show?
- Sat Oct 21, 2017 4:07 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: electron configurations [ENDORSED]
- Replies: 2
- Views: 324
Re: electron configurations [ENDORSED]
you can write 2p^2. Prof Lavelle said that he accepts both ways of writing it. It's just that writing 2px^1 and 2py^1 is more specific and prevents ambiguity to electron spin.
- Sat Oct 21, 2017 4:06 pm
- Forum: Wave Functions and s-, p-, d-, f- Orbitals
- Topic: Principle Quantum Number [ENDORSED]
- Replies: 3
- Views: 376
Principle Quantum Number [ENDORSED]
What exactly is the principle quantum number? I'm not fully understanding the concept.
- Fri Oct 13, 2017 9:09 pm
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: 1.6b
- Replies: 2
- Views: 407
Re: 1.6b
use the equation (lambda = h/p)......h is Planck's constant (6.626 x 10^-34) and p is momentum (mass x velocity). So with the given mass of the bullet and the velocity, calculate the momentum. Then do Planck's constant/momentum and you will get wavelength.
I hope this helps
I hope this helps
- Wed Oct 11, 2017 2:16 am
- Forum: Heisenberg Indeterminacy (Uncertainty) Equation
- Topic: Post Module Q. 14
- Replies: 3
- Views: 582
Post Module Q. 14
14. For large everyday objects does Heisenberg's uncertainty (indeterminacy) principle play any measurable role? A. Yes, the uncertainties in position, speed, and momentum of a stationary object are noticeable or measurable. B. Yes, the uncertainties in position, speed, and momentum of a moving obje...
- Tue Oct 10, 2017 5:14 pm
- Forum: DeBroglie Equation
- Topic: Post-Module Assessment Q. 34
- Replies: 4
- Views: 449
Post-Module Assessment Q. 34
If an electron (mass 9.11 x 10^-31 kg) has an associated wavelength of 7.28 x 10^-9 m, what is its speed? Is your answer reasonable, why? A. 1.00 x 10-5 m.s-1. Yes. 1.00 x 10-5 m.s-1 is reasonable for e- as it is less than the speed of light, c = 3.0 x 108m.s-1. B.1.00 x 10-5 m.s-1. No. 1.00 x 10-5 ...
- Sun Oct 08, 2017 3:39 pm
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect: Post Module Assessment Q. 28, 29, and 30
- Replies: 12
- Views: 1392
Re: Photoelectric Effect: Post Module Assessment Q. 28, 29, and 30
28. Light hits a sodium metal surface and the velocity of the ejected electron is 6.61 x 105 m.s-1. The work function for sodium is 150.6 kJ.mol-1. Answer the following three questions. A. What is the kinetic energy of the ejected electron? A. 3.01 x 10^25 J B. 3.98 x 10^-19 J C. 7.96 x 10^-19 J D. ...
- Sun Oct 08, 2017 3:29 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic Spectra Post-Module Assessment Q. 42
- Replies: 1
- Views: 243
Atomic Spectra Post-Module Assessment Q. 42
42. An excited hydrogen atom emits light with a frequency of 1.14 x 1014 Hz to reach the energy level n = 4. In what principle quantum level did the electron begin?
A. n = 5
B. n = 6
C. n = 4
D. n = 7
How do you do this?
A. n = 5
B. n = 6
C. n = 4
D. n = 7
How do you do this?
- Sun Oct 08, 2017 3:15 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Atomic Spectra Post-Module Assessment Q. 20 [ENDORSED]
- Replies: 2
- Views: 397
Atomic Spectra Post-Module Assessment Q. 20 [ENDORSED]
20. If 1 million photons in the UV region are absorbed by a hydrogen gas sample how many electrons are excited to a higher energy level?
A) Zero
B) 500,000
C) 1
D) 1 Million
I put my answer as 1 because I thought hydrogen has only 1 electron. So how is the answer incorrect?
A) Zero
B) 500,000
C) 1
D) 1 Million
I put my answer as 1 because I thought hydrogen has only 1 electron. So how is the answer incorrect?
- Sun Oct 08, 2017 12:28 am
- Forum: Photoelectric Effect
- Topic: Photoelectric Effect: Post Module Assessment Q. 28, 29, and 30
- Replies: 12
- Views: 1392
Photoelectric Effect: Post Module Assessment Q. 28, 29, and 30
How do you do questions 28, 29, and 30 in the post assessment module for the photoelectric effect?
- Sun Oct 08, 2017 12:26 am
- Forum: Photoelectric Effect
- Topic: Question from online assessment [ENDORSED]
- Replies: 1
- Views: 196
Re: Question from online assessment [ENDORSED]
The light from the UV range of the electromagnetic spectrum tends to have higher frequencies which means the photons have more energy to overcome the threshold energy of the metal.
- Wed Oct 04, 2017 10:02 pm
- Forum: Limiting Reactant Calculations
- Topic: Page F109 from book (Self-Test M.2A)
- Replies: 2
- Views: 644
Page F109 from book (Self-Test M.2A)
How do you identify the limiting reactant in the reaction 6 Na + Al2O3 ->2 Al + 3 Na2O when 5.52 g of sodium is heated with 5.1 g of Al2O3?
- Mon Oct 02, 2017 7:22 pm
- Forum: Balancing Chemical Reactions
- Topic: Fundamental H.13
- Replies: 4
- Views: 771
Re: Fundamental H.13
Cool thanks, and how do you balance Fe2O3 + CO -> Fe3O4 + CO2 from the first part of H.11?
- Mon Oct 02, 2017 7:05 pm
- Forum: Balancing Chemical Reactions
- Topic: Fundamental H.13
- Replies: 4
- Views: 771
Fundamental H.13
In this question, we are asked to balance NO+O2 -> NO2 in the second part of the problem.
I know this seems easy, but I can't wrap my head around balancing it. How do you do it (step by step)?
I know this seems easy, but I can't wrap my head around balancing it. How do you do it (step by step)?