Search found 30 matches
- Tue Jun 12, 2018 3:16 am
- Forum: Student Social/Study Group
- Topic: Post All Chemistry Jokes Here
- Replies: 9651
- Views: 3671857
Re: Post All Chemistry Jokes Here
I don't trust atoms...I heard they make up everything.
- Sat Jun 02, 2018 9:00 pm
- Forum: Electronegativity
- Topic: Calculating electronegativity
- Replies: 10
- Views: 1337
Re: Calculating electronegativity
we do not need to know how to calculate electronegativities. However, the trend is that EN increases towards an upwards diagonal to the right. it decreases down a column and increases across a row.
- Sat Jun 02, 2018 8:55 pm
- Forum: Electronegativity
- Topic: Test 3. Question 7.
- Replies: 6
- Views: 1071
Re: Test 3. Question 7.
Differences in electronegavity determine the ionic character. the higher the difference in electronegativity, the greater the ionic character
- Sat Jun 02, 2018 8:51 pm
- Forum: Sigma & Pi Bonds
- Topic: Detail of Bonds
- Replies: 3
- Views: 607
Re: Detail of Bonds
a sigma bond is one single covalent bond
so for single, double, and triple bonds,
a single bond=1 sigma bond
a double bond=1 sigma bond+1 pi bond
a triple bond=1 sigma bond+2 pi bonds
so for single, double, and triple bonds,
a single bond=1 sigma bond
a double bond=1 sigma bond+1 pi bond
a triple bond=1 sigma bond+2 pi bonds
- Sat Jun 02, 2018 8:49 pm
- Forum: Resonance Structures
- Topic: Resonance Structures
- Replies: 9
- Views: 1157
Re: Resonance Structures
No, resonance structures do not have to have the same formal charge for each element. however, the overall formal charge should be the same. For example, if it was No3-, overall it should have a -1 formal charge for the -
- Sat Jun 02, 2018 8:46 pm
- Forum: Hybridization
- Topic: VSEPR
- Replies: 11
- Views: 1559
Re: VSEPR
VSEPR stands for valence shell electron pair repulsion and it achieves the geometry that has the least electron repulsion
- Sat Jun 02, 2018 8:45 pm
- Forum: Hybridization
- Topic: σ bonds
- Replies: 9
- Views: 1076
Re: σ bonds
a sigma bond is when there is one single covalent bond
however, double bonds and triple bonds also have a sigma bond
however, double bonds and triple bonds also have a sigma bond
- Wed May 23, 2018 1:26 am
- Forum: Ionic & Covalent Bonds
- Topic: Octet rule
- Replies: 17
- Views: 2432
Re: Octet rule
atoms are most stable when they have eight electrons. However, there are exceptions to this like hydrogen which only has one electron.
- Wed May 23, 2018 1:23 am
- Forum: Lewis Structures
- Topic: lowest energy & most stable Lewis structures
- Replies: 4
- Views: 2709
Re: lowest energy & most stable Lewis structures
you would have to calculate the formal charge by the equation:
formal charge = number of valence - lone electrons - (shared electrons/2)
formal charge = number of valence - lone electrons - (shared electrons/2)
- Wed May 23, 2018 1:22 am
- Forum: Lewis Structures
- Topic: H Formal Charge
- Replies: 4
- Views: 513
Re: H Formal Charge
Hydrogen really only has one electron even when bonding and there is no exception to that, so when Hydrogen has only one electron (which is always the case) it has a formal charge of 0
- Wed May 23, 2018 1:20 am
- Forum: Ionic & Covalent Bonds
- Topic: Formal charge?
- Replies: 12
- Views: 1446
Re: Formal charge?
you calculate formal charge by using the equation
number of valence electrons - number of lone electrons and number of bonds
number of valence electrons - number of lone electrons and number of bonds
- Wed May 23, 2018 1:18 am
- Forum: Ionic & Covalent Bonds
- Topic: ionic character
- Replies: 10
- Views: 1039
Re: ionic character
greater ionic character means greater difference in electronegativity
- Wed May 23, 2018 1:15 am
- Forum: Determining Molecular Shape (VSEPR)
- Topic: VSEPR on test 3?
- Replies: 3
- Views: 491
VSEPR on test 3?
Will VSEPR be on test three? or is it just lewis structures?
- Sat Apr 28, 2018 1:05 am
- Forum: Properties of Electrons
- Topic: Information Provided on Exam
- Replies: 6
- Views: 760
Re: Information Provided on Exam
No this will not be provided
- Sat Apr 28, 2018 1:04 am
- Forum: Properties of Light
- Topic: Rydberg Formula for Atomic Hydrogen [ENDORSED]
- Replies: 4
- Views: 958
Re: Rydberg Formula for Atomic Hydrogen [ENDORSED]
it's E(n) = -(hR)/nfinal^2 -(hR)/ninitial^2
and for frequency it is = R [(1/nfinal^2) - (1/ninitial^2)]
and for frequency it is = R [(1/nfinal^2) - (1/ninitial^2)]
- Tue Apr 24, 2018 11:53 pm
- Forum: Photoelectric Effect
- Topic: Frequency on Photoelectric Effect
- Replies: 5
- Views: 652
Frequency on Photoelectric Effect
If a certain frequency is not ejecting electrons. Does increasing frequency eject electrons?
Also what increases the number of electrons ejected?
Also what increases the number of electrons ejected?
- Thu Apr 19, 2018 1:59 am
- Forum: Photoelectric Effect
- Topic: Lyman vs. Balmer vs. Paschen vs. Brackett?
- Replies: 3
- Views: 1377
Lyman vs. Balmer vs. Paschen vs. Brackett?
What are the differences between these three series and how do I tell the difference between them?
For example, in problem 1.13 problem b, why is the answer Balmer?
For example, in problem 1.13 problem b, why is the answer Balmer?
- Tue Apr 17, 2018 11:59 am
- Forum: Limiting Reactant Calculations
- Topic: moles + limiting reactant
- Replies: 2
- Views: 448
Re: moles + limiting reactant
you find the moles of each and compare it to the ratios in the chemical equation
or you can use both and the balanced chemical equation see which one produces less product
or you can use both and the balanced chemical equation see which one produces less product
- Tue Apr 17, 2018 11:54 am
- Forum: Ideal Gases
- Topic: Reading the textbook
- Replies: 262
- Views: 152382
Re: Reading the textbook
I get overwhelmed and intimidated when reading the textbook too, so I would recommend only doing so when you have your full attention to the book and no other distractions.
- Tue Apr 17, 2018 11:52 am
- Forum: Ionic & Covalent Bonds
- Topic: Types of Bonds
- Replies: 10
- Views: 1265
Re: Types of Bonds
A covalent bond would just be between two nonmetals while an ionic bond is between a nonmetal and a metal! just look at the two elements in the chemical equation
- Thu Apr 12, 2018 3:53 am
- Forum: Molarity, Solutions, Dilutions
- Topic: Problem G13
- Replies: 1
- Views: 388
Problem G13
I need help on the following problem (G13 in the textbook): To prepare a fertilizer solution, a florist dilutes 1.0 L of 0.20 m NH4NO3(aq) by adding 3.0 L of water. The florist then adds 100. mL of the diluted solution to each plant. How many moles of nitrogen atoms will each plant receive? Solve th...
- Wed Apr 11, 2018 12:30 am
- Forum: Photoelectric Effect
- Topic: Module Question 27.A
- Replies: 4
- Views: 457
Re: Module Question 27.A
with the equation 1/2 times mv^2, you use the KJ/mol to covert the mols to kg for the m part in the equation. The m stands for mass, so you need to convert the mols to kg. Then, Kinetic energy is measure in Joules which is already used in the equation, so some units should cancel out.
- Wed Apr 11, 2018 12:18 am
- Forum: Limiting Reactant Calculations
- Topic: Mass of Products VS. Mass of Reactants- Class Assessment
- Replies: 5
- Views: 3155
Re: Mass of Products VS. Mass of Reactants- Class Assessment
No; based on the law of conservation of mass, the amount of products is equal to the mass of the reactants since this mass is not created nor destroyed in chemical reactions. They are just bonded differently.
- Wed Apr 11, 2018 12:16 am
- Forum: Balancing Chemical Reactions
- Topic: Subscripts [ENDORSED]
- Replies: 6
- Views: 919
Re: Subscripts [ENDORSED]
This means that there are 6N and and only 1 Mn. You would have to take into consideration both elements when balancing the equations. You would generally balance the one that is by itself on the other side last or balance the one first that is easiest to balance corresponding to the other side.
- Wed Apr 11, 2018 12:13 am
- Forum: Significant Figures
- Topic: Scientific notation [ENDORSED]
- Replies: 7
- Views: 991
Re: Scientific notation [ENDORSED]
I think either is fine, but generally in chemistry, scientific notation is used. However, Lavelle did mention that significant figures do not matter in this course.
- Wed Apr 11, 2018 12:11 am
- Forum: Properties of Electrons
- Topic: Electromagnetic Field [ENDORSED]
- Replies: 7
- Views: 857
Re: Electromagnetic Field [ENDORSED]
I agree. I also think it's arbitrary. None of them technically point upward or to the right, it is just a matter of how they are viewed and at what angles.
- Wed Apr 11, 2018 12:05 am
- Forum: SI Units, Unit Conversions
- Topic: Units for Answer
- Replies: 10
- Views: 1198
Re: Units for Answer
Most often if it is talking about mass then you would revert back to kg since it is one of the standard units. The standard units are kg, m, and sec which is what are normally used.
- Fri Apr 06, 2018 2:18 pm
- Forum: Significant Figures
- Topic: Sig Figs [ENDORSED]
- Replies: 9
- Views: 989
Re: Sig Figs [ENDORSED]
No. Someone asked Lavelle if significant figures matter on tests, and he said no.
- Fri Apr 06, 2018 2:16 pm
- Forum: Empirical & Molecular Formulas
- Topic: Periodic Table Memorization [ENDORSED]
- Replies: 8
- Views: 863
Re: Periodic Table Memorization [ENDORSED]
No. We do not need memorize the periodic table components for the first exam! I'm sure they will provide us with needed information and periodic table if necessary.
- Fri Apr 06, 2018 11:37 am
- Forum: Administrative Questions and Class Announcements
- Topic: Modules
- Replies: 5
- Views: 676
Re: Modules
They are just posted for extra help on exam materials and used for guidance!