Search found 114 matches
- Wed Oct 14, 2020 10:49 pm
- Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
- Topic: Sapling Week 2 & 3 HW Problem 5
- Replies: 7
- Views: 217
Sapling Week 2 & 3 HW Problem 5
Hi everyone! I'm working on the Week 2 & 3 homework and am stuck on problem 5. The problem is: The electron in a hydrogen atom is excited to the n=7 shell and emits electromagnetic radiation when returning to lower energy levels. Determine the number of spectral lines that could appear when this...
- Wed Oct 14, 2020 9:34 pm
- Forum: DeBroglie Equation
- Topic: Practice Problem 1B #15
- Replies: 2
- Views: 106
Re: Practice Problem 1B #15
I attempted this problem using the equation Ek=1/2mv^2 to get the kinetic energy value for the ejected electron, and then tried to get the wavelength by using the E=hc/λ equation. I tripled checked my work and still never managed to get the same wavelength that the answer key states. I don't know wh...
- Tue Oct 13, 2020 9:49 pm
- Forum: Properties of Electrons
- Topic: Textbook 1A.15
- Replies: 3
- Views: 145
Re: Textbook 1A.15
I was stuck on the same problem! I'm wondering if Dr. Lavelle will get into more information about spectral lines in his next lecture tomorrow morning?
- Tue Oct 13, 2020 1:16 pm
- Forum: Molarity, Solutions, Dilutions
- Topic: G.25
- Replies: 2
- Views: 57
Re: G.25
Since diluting the original solution will not change the number of molecules of solute in the solution, the number of X molecules that are present in the .1M solution will be equal to the number of X molecules present after it's been diluted. As for the health benefits, diluting the solution 90 time...
- Tue Oct 13, 2020 12:03 pm
- Forum: SI Units, Unit Conversions
- Topic: Nomenclature
- Replies: 7
- Views: 316
Re: Nomenclature
Yes! In office hours yesterday, when someone asked this same question, Dr. Lavelle assured us that he will always provide both the compound name and its molecular formula on exams. I believe he said that he likes to provide us with the compound name and formula in order to test on what the problem i...
- Fri Oct 09, 2020 10:05 pm
- Forum: Administrative Questions and Class Announcements
- Topic: Midterm(s?)
- Replies: 6
- Views: 167
Re: Midterm(s?)
Yes, it says on the syllabus that midterms will be 50 minutes closed note and TA proctored.
- Fri Oct 09, 2020 10:02 pm
- Forum: Student Social/Study Group
- Topic: Regarding Quizzes
- Replies: 5
- Views: 166
Re: Regarding Quizzes
I'm not sure if we will be having any quizzes... they aren't mentioned on the syllabus. Or are there quizzes that I haven't heard about?
- Wed Oct 07, 2020 3:30 pm
- Forum: Limiting Reactant Calculations
- Topic: Question about Molar Ratios with Limiting Reactants
- Replies: 8
- Views: 312
Re: Question about Molar Ratios with Limiting Reactants
The way that I usually approach problem solving examples like yours is I'll find how many moles of each reactant are present, and then I'll multiply whichever reactant that has the smallest stoichiometric coefficient in the balanced equation by the other coefficients to determine which is the limiti...
- Wed Oct 07, 2020 3:16 pm
- Forum: Limiting Reactant Calculations
- Topic: Help Determining a Chemical Equation
- Replies: 5
- Views: 263
Re: Help Determining a Chemical Equation
Ok, makes perfect sense! Thank you both.
- Wed Oct 07, 2020 2:59 pm
- Forum: Limiting Reactant Calculations
- Topic: Help Determining a Chemical Equation
- Replies: 5
- Views: 263
Re: Help Determining a Chemical Equation
Thanks for the info! I'm still confused though, if it takes 1 Al atom with a +3 charge to cancel out the -3 charge of 1 Cl then shouldn't the molecular formula of aluminum chloride be just AlCl? Why are there 3 Al atoms in AlCl3? Also, the molecular formula of chlorine is Cl2--how do I determine tha...
- Wed Oct 07, 2020 1:29 pm
- Forum: Balancing Chemical Reactions
- Topic: Fractions
- Replies: 25
- Views: 1488
Re: Fractions
Stoichiometric coefficients are more effective when they're written in whole numbers, so I'm assuming that points will be deducted for coefficients written in fraction form. The calculation to turn these a coefficient from a fraction to a whole number is extremely simple though, you just need to mul...
- Wed Oct 07, 2020 1:25 pm
- Forum: Limiting Reactant Calculations
- Topic: Help Determining a Chemical Equation
- Replies: 5
- Views: 263
Help Determining a Chemical Equation
Here is a problem from my discussion group that I'm having trouble starting (it's question M15 from the book): Aluminum metal reacts with chlorine gas to produce aluminum chloride. In one preparation, 255 g of aluminum is placed in a container holding 535 g of chlorine gas. After reaction ceases, it...
- Wed Oct 07, 2020 1:14 pm
- Forum: Limiting Reactant Calculations
- Topic: Sapling Question 10
- Replies: 4
- Views: 194
Re: Sapling Question 10
Does anybody know if we'll be expected to know how to derive molecular formulas from incomplete diagrams like this for the rest of the quarter? Or should we expect to be given molecular formulas in the majority of test questions?
- Sun Oct 04, 2020 12:36 pm
- Forum: Balancing Chemical Reactions
- Topic: Mass conservation in chemical reactions [ENDORSED]
- Replies: 3
- Views: 850
Re: Mass conservation in chemical reactions [ENDORSED]
The easiest way for me to understand the law of conservation of mass in the setting of a chemical reaction is this is to think about what is happening on a molecular level during any type of chemical reaction. Chemical reactions involve the reshuffling, or rearranging of atoms (in the reactants) int...