Search found 54 matches

by NRobbins_1K
Thu Dec 05, 2019 1:22 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Difference between chelating ligand and polydentate ligand
Replies: 4
Views: 96

Re: Difference between chelating ligand and polydentate ligand

sorry if its too late

https://chem.libretexts.org/Bookshelves ... _Chemistry)/
Coordination_Chemistry/Structure_and_Nomenclature_of_Coordination_Compounds/Ligands

hopefully that works
by NRobbins_1K
Tue Dec 03, 2019 4:53 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Atomic Spectra
Replies: 3
Views: 132

Re: Atomic Spectra

Usually, if given the energy levels, we will use the Rydberg equation to find frequency and then use E = hv to find the energy.
by NRobbins_1K
Tue Dec 03, 2019 4:48 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: deprotonation and protonation
Replies: 3
Views: 53

Re: deprotonation and protonation

To answer the last part of your question, a strong acid will completely dissociate and thus for every mole of acid that gives off a H+ ion, one mole of water is protonated. This ratio will be significantly less for a weak acid.
by NRobbins_1K
Tue Dec 03, 2019 4:47 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: deprotonation and protonation
Replies: 3
Views: 53

Re: deprotonation and protonation

Perhaps I am misunderstanding your question, but I am confused by your use of the term protonation. A reaction cannot be protonated- we refer to a given molecule as being either protonated or deprotonated. The concept is fairly simple- if a proton (H+ ion) is added to the compound, it is proton-ated...
by NRobbins_1K
Tue Dec 03, 2019 4:43 pm
Forum: Sigma & Pi Bonds
Topic: Unhybridized orbitals.
Replies: 3
Views: 110

Re: Unhybridized orbitals.

In an sp3 hybridization state, all of the p orbitals are hybridized (there are three p orbitals, and note that sp3 accounts for all 3). In order for a pi bond to form, there needs to be at least one unhybridized p orbital. This means that sp2 only accounts for 2 out of the 3 p orbitals, meaning ther...
by NRobbins_1K
Tue Dec 03, 2019 4:38 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Difference between chelating ligand and polydentate ligand
Replies: 4
Views: 96

Re: Difference between chelating complex and polydentate ligand

As far as I can tell from doing a bit of research, polydentate is always synonymous with chelating and monodentate with nonchelating. Reading through this page led me to that conclusion. https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Supplemental_Modules_(Inorganic_Chemistry)/Coordinati...
by NRobbins_1K
Mon Dec 02, 2019 5:41 pm
Forum: Lewis Acids & Bases
Topic: Electron Donating/Accepting
Replies: 2
Views: 53

Re: Electron Donating/Accepting

We talked about Lewis acids and bases mostly in the context of coordination compounds, so I'll explain it in that context too. In a coordination compound, the Lewis acid (electron pair acceptor) is the positively charged transition metal. Notice that even though it is positively charged, !! it doesn...
by NRobbins_1K
Mon Dec 02, 2019 5:30 pm
Forum: Lewis Structures
Topic: 2.61
Replies: 2
Views: 140

Re: 2.61

I believe this is because in the radical carbon actually has one less electron than it needs for an octet, not one more. Because the oxygens are more electronegative, they are the first to 'get' electrons and receive a full octet. Carbon, being less electronegative, has less power to gain the electr...
by NRobbins_1K
Mon Dec 02, 2019 5:22 pm
Forum: Conjugate Acids & Bases
Topic: Strong vs Weak
Replies: 2
Views: 40

Re: Strong vs Weak

The simplest way to tell that an acid/base is weak is if you are given an eq. constant. This automatically means it is weak because it is not 100% dissociated. Other easy ways include seeing a carboxylic acid group CH3COOH, which indicates an organic/weak acid.
by NRobbins_1K
Mon Dec 02, 2019 5:18 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Strong vs. Weak Acids and Bases
Replies: 4
Views: 51

Re: Strong vs. Weak Acids and Bases

I would try to avoid memorizing which things make an acid/base strong or weak and focus on understanding WHY certain traits contribute to strength or weakness. For example, you could just memorize the fact that when you are given an equilibrium constant, it means the acid/base is weak. However, I wo...
by NRobbins_1K
Sun Dec 01, 2019 7:51 pm
Forum: Identifying Acidic & Basic Salts
Topic: Salt
Replies: 5
Views: 63

Re: Salt

It depends on the salt- certain salts tend to make water more acidic, some make it more alkaline, and some- like table salt- don’t change the pH of water at all because they don’t react with the water to create hydronium or hydroxide ions
by NRobbins_1K
Sun Dec 01, 2019 7:13 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Polydentates and Chelates
Replies: 2
Views: 27

Re: Polydentates and Chelates

I think there might be a misunderstanding about the structure of a chelate. A chelate consists of one metal atom and one ligand- a single compound which can have multiple binding sites on the same metal atom. For example, a tetradentate ligand is one single compound that binds to one metal atom in f...
by NRobbins_1K
Sun Dec 01, 2019 7:01 pm
Forum: Lewis Acids & Bases
Topic: Bases
Replies: 4
Views: 44

Re: Bases

As with acids, if you are given an equilibrium constant in a problem it is a clue that the base in question is not strong, because an equilibrium constant indicates incomplete dissociation. As with the rest of the clues that we learned that indicate a strong versus a weak acid, you can use this to t...
by NRobbins_1K
Sun Dec 01, 2019 6:55 pm
Forum: Naming
Topic: Anionic Ligands
Replies: 1
Views: 22

Re: Anionic Ligands

So far, if I recall correctly we haven’t yet had a test where we were expected to have memorized the formula for any compound. I doubt the anionic ligands will be an exception.
by NRobbins_1K
Sun Dec 01, 2019 6:52 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Ligand Binding Sites
Replies: 1
Views: 21

Re: Ligand Binding Sites

Ligands with four binding sites are called tetradentate and with 5, pentadentate. they are rare but they exist, for example porphyrin is tetradentate.
by NRobbins_1K
Thu Nov 28, 2019 11:28 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Week 9 homework
Replies: 11
Views: 157

Re: Week 9 homework

there was an email sent out that said homework for weeks 9 and 10 is due week 10 in discussion.
by NRobbins_1K
Tue Nov 26, 2019 4:13 pm
Forum: Sigma & Pi Bonds
Topic: Question on Test 2
Replies: 11
Views: 336

Re: Question on Test 2

The question asked us to identify every bond in the molecule. Every single bond contains one sigma bond, every double bond contains one of each of pi and sigma bonds, and triple bonds (which I don't believe were on that question) contain two pi bonds and one sigma bond. As for the hydrogen bonding c...
by NRobbins_1K
Tue Nov 26, 2019 4:08 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Complexes
Replies: 2
Views: 38

Re: Complexes

In class, dr. Lavelle said that we are not expected to be able to tell the difference between the two complexes that contain 4 ligands (tetrahedral and square planar) but that we would need to tell the difference between those two and octahedral complexes, which have 6 ligands. If the naming is conf...
by NRobbins_1K
Sun Nov 24, 2019 8:52 pm
Forum: Biological Examples
Topic: Heme complex and biological significance
Replies: 2
Views: 39

Re: Heme complex and biological significance

The heme complex is the combination of a porphyrin tetradentate ligand and an iron atom. The heme complex is incorporated into proteins like myoglobin and hemoglobin and they allow the iron molecule to bind to molecular oxygen O2 and transport it along with the protein to various parts of the body.
by NRobbins_1K
Sun Nov 24, 2019 8:44 pm
Forum: Biological Examples
Topic: Biological Significance
Replies: 3
Views: 62

Biological Significance

Can someone explain what the biological importance of transition metals is? How are they used and what makes them useful?
by NRobbins_1K
Sun Nov 24, 2019 8:38 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Ligands
Replies: 5
Views: 77

Re: Ligands

First, look at the overall charge of the compound. Whatever it is, the negative charges of the ions and the positive charges of the transition metal must add to that overall charge. If the overall molecule is neutral, but there are two ligands with a charge of -1 each, then the oxidation state of th...
by NRobbins_1K
Sun Nov 24, 2019 8:33 pm
Forum: Lewis Acids & Bases
Topic: Lewis acids + bases and Bronsted acids + bases
Replies: 6
Views: 83

Re: Lewis acids + bases and Bronsted acids + bases

lewis acids and bases are defined as electron pair acceptors and receptors respectively. bronsted acids/bases are defined in reference to hydrogen donation or receiving, and bronsted acids donate protons and bases receive them
by NRobbins_1K
Sun Nov 24, 2019 8:28 pm
Forum: Naming
Topic: Meaning of Cis and Trans
Replies: 11
Views: 146

Meaning of Cis and Trans

Can someone explain the difference between cis and trans and how that applies to cisplatin?
by NRobbins_1K
Fri Nov 15, 2019 10:31 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Bond Angle
Replies: 3
Views: 37

Re: Determining Bond Angle

This website has a good chart for conceptualizing and memorizing how the bond angles change for each molecular shape

https://courses.lumenlearning.com/intro ... eometries/
by NRobbins_1K
Fri Nov 15, 2019 10:26 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Other shapes
Replies: 3
Views: 35

Re: Other shapes

This website has a good chart for memorizing the names of the molecular shapes. When seen in this form it's easier to conceptualize since it becomes clear that they follow a pattern.

https://courses.lumenlearning.com/intro ... eometries/
by NRobbins_1K
Fri Nov 15, 2019 10:23 am
Forum: General Science Questions
Topic: Test 2
Replies: 4
Views: 81

Re: Test 2

The test is on everything after the content covered on the midterm. This includes everything we have learned about molecular structure and VSEPR. Expect to be drawing lots of Lewis structures.
by NRobbins_1K
Fri Nov 15, 2019 10:21 am
Forum: Interionic and Intermolecular Forces (Ion-Ion, Ion-Dipole, Dipole-Dipole, Dipole-Induced Dipole, Dispersion/Induced Dipole-Induced Dipole/London Forces, Hydrogen Bonding)
Topic: 3F problem 3
Replies: 3
Views: 63

Re: 3F problem 3

It's about the charge symmetry of the molecule. If the electronegativity is evenly distributed around the central atom then it will not be polar since there is no net charge, but if certain regions attract electrons more strongly then there will be a partial charge and polarity will occur. The way t...
by NRobbins_1K
Fri Nov 15, 2019 10:19 am
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR Formula Notation
Replies: 4
Views: 50

VSEPR Formula Notation

What is the significance of A, X and E in the formula? What does each letter stand for?
by NRobbins_1K
Fri Nov 15, 2019 10:15 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining Lone Pair Location
Replies: 3
Views: 49

Determining Lone Pair Location

When drawing a Lewis structure, how can one know the location of lone pairs around a central atom? For example, in IF4, how can you ascertain that the lone pairs are on opposite sides of the molecule rather than being adjacent to each other like in ICl3-?
by NRobbins_1K
Sun Nov 03, 2019 10:38 pm
Forum: Ionic & Covalent Bonds
Topic: Valence electrons of transition metals
Replies: 2
Views: 69

Re: Valence electrons of transition metals

The idea of valence electrons kind of breaks down when you get to elements that contain the D orbitals. Instead, the idea of 'outer electrons' makes more sense, in which you count the number of electrons after the previous noble gas configuration.
by NRobbins_1K
Sun Nov 03, 2019 10:30 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Module Clarification
Replies: 1
Views: 55

Re: Photoelectric Effect Module Clarification

The work function is given to us in kJ/mole, but we need the energy in the form of joules per atom in order to use the formula to calculate for energy. Therefore, we divide by the number of atoms in a mole (Avogadro's number) to convert moles into atoms.
by NRobbins_1K
Sun Nov 03, 2019 10:27 pm
Forum: Formal Charge and Oxidation Numbers
Topic: formal charge
Replies: 5
Views: 79

Re: formal charge

When drawing Lewis structures, it is necessary to make sure that the structure represents the lowest possible energy state. Calculating formal charge is one way to confirm that the structure you have drawn is the lowest possible energy structure for that compound. Atoms will always take the structur...
by NRobbins_1K
Sun Nov 03, 2019 10:23 pm
Forum: Electronegativity
Topic: 2D.7
Replies: 2
Views: 52

Re: 2D.7

You shouldn't need to calculate the electronegativities of compounds but rather you should look at the relative electronegativities of the elements that make up those compounds. A covalent bond between atoms with similar electronegativites will have more covalent character (and thus less readily dis...
by NRobbins_1K
Sun Nov 03, 2019 10:20 pm
Forum: Lewis Structures
Topic: Resonance
Replies: 5
Views: 47

Re: Resonance

Resonance occurs in many compounds and is present when multiple correct Lewis structures of equal energy can be drawn. They simply occur often in molecules with oxygen because oxygen readily forms double bonds which are often delocalized causing resonance.
by NRobbins_1K
Sun Nov 03, 2019 10:14 pm
Forum: Balancing Chemical Reactions
Topic: Balancing Chemical Equations
Replies: 4
Views: 169

Re: Balancing Chemical Equations

after some work, I came up with 6 NH4ClO4 + 10 Al = 5 Al2O3 + 9 H2O + 6 HCl + 3 N2 the key for me was realizing that NH4ClO4 could only occur in even increments (since N2 in the products can only be a whole number for multiples of two) and that the coefficient for NH4ClO4 would always equal the coef...
by NRobbins_1K
Sun Oct 27, 2019 11:21 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge and Covalent Bonds
Replies: 3
Views: 63

Re: Formal Charge and Covalent Bonds

This could be incorrect, but I think this has to do with the idea that all bonds have some ionic and some covalent characteristics. A pure covalent bond has a formal charge of 0, and that's why when trying to draw Lewis structures we look for the combinations that have the closest formal charge to 0...
by NRobbins_1K
Sun Oct 27, 2019 11:13 pm
Forum: Quantum Numbers and The H-Atom
Topic: Subshells
Replies: 2
Views: 54

Re: Subshells

for a) 2d cannot exist because the 'd' orbitals do not ever exist in the '2' energy shell. The 'd' orbital first occurs in the 3rd shell, so the first 'd' subshell is 3d. The same logic applies for c) 4g. The first 'g' subshell occurs in the 5th shell, and only 5g,6g,7g etc are possible.
by NRobbins_1K
Sun Oct 27, 2019 11:10 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Memorizing the Equation
Replies: 4
Views: 86

Re: Memorizing the Equation

I imagine that on a test we will be given that equation, so if you want to memorize it anyway that's great but you probably won't need to. As far as remembering the equation, I think of it in terms of starting with the 'total' available (V) and subtracting the 'parts' that could be arranged in diffe...
by NRobbins_1K
Wed Oct 16, 2019 11:05 pm
Forum: Quantum Numbers and The H-Atom
Topic: Stern and Gerlach
Replies: 5
Views: 58

Re: Stern and Gerlach

Essentially the experiment proved that there was an intrinsic, binary property of an electron that influenced its behavior in a magnetic field. This property was termed the magnetic spin of the electron, and is the fourth quantum number used to describe the state of an electron in an atom. It can be...
by NRobbins_1K
Tue Oct 15, 2019 6:41 pm
Forum: Quantum Numbers and The H-Atom
Topic: question on 1A.11
Replies: 1
Views: 60

Re: question on 1A.11

I doubt that we would need to memorize it. However, the concept is pretty simple- the Paschen and Brackett series simply represent transitions (of an electron in a hydrogen atom) from high energy levels (n=5,6, etc) to the n=3 and n=4 energy levels respectively. This is simply a continuation of the ...
by NRobbins_1K
Tue Oct 15, 2019 6:33 pm
Forum: Properties of Electrons
Topic: 1B.3
Replies: 3
Views: 73

Re: 1B.3

The observation that indicates particle like behavior in EM radiation is the photoelectric effect. Recall that the experimenters were expecting light to act like a wave, and therefore they expected that increasing the intensity of the light would cause electrons to be ejected even if there was no ch...
by NRobbins_1K
Tue Oct 15, 2019 6:24 pm
Forum: Properties of Light
Topic: Balmer and Lyman
Replies: 1
Views: 30

Re: Balmer and Lyman

The Balmer and Lyman series represent the wavelengths of light emitted when an electron in a hydrogen atom transitions from a high energy level (n=3,4,5,etc) to the n=1 energy level (Lyman) or the n=2 energy level (Balmer). Since more energy is released when the electron transfers to the lowest ener...
by NRobbins_1K
Tue Oct 15, 2019 6:12 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty Measurement Clarification
Replies: 2
Views: 39

Uncertainty Measurement Clarification

When inputting a value for uncertainty into the equation, do we use the full range of values or the "plus or minus" value? For example, say that we are given an uncertainty for position of +- 5 meters. Do we input an uncertainty of 5 for the position, or the range of uncertainty which woul...
by NRobbins_1K
Thu Oct 10, 2019 10:26 am
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: HW question spectral line
Replies: 1
Views: 49

Re: HW question spectral line

When looking at the absorption spectrum of a gas, the gas itself is not emitting any light. White light is shone through the sample and the gas absorbs some wavelengths while leaving the rest, so the result being detected is a nearly complete spectrum with only a few wavelengths missing. In an emiss...
by NRobbins_1K
Thu Oct 10, 2019 10:11 am
Forum: Photoelectric Effect
Topic: HW 1B15
Replies: 1
Views: 44

Re: HW 1B15

This is a question asking about the quantum principle of the wavelength of matter, which can be found using De Broglie's equation, l (wavelength) = h / mv where h is Plank's constant, m is the mass of the object and v is it's velocity. We know that the mass of an electron is 9.109×10^31 kg, Plank's ...
by NRobbins_1K
Thu Oct 10, 2019 9:59 am
Forum: Empirical & Molecular Formulas
Topic: Question E9
Replies: 4
Views: 104

Re: Question E9

You can simply look it up, but the naming conventions are useful to memorize. "Sulfate" represents the ion SO4 which has a 2- charge. Since Magnesium has a charge of 2+, it pairs 1:1 with a sulfate ion, so the formula for magnesium sulfate is MgSO4. "Hydrate" indicates a water mo...
by NRobbins_1K
Mon Oct 07, 2019 4:47 pm
Forum: Limiting Reactant Calculations
Topic: Homework Problem L.1
Replies: 2
Views: 83

Re: Homework Problem L.1

This problem asks you to infer that the limiting reactant will be ClO2 -- since the amount of the other reactant is not mentioned we can assume it is in excess. Since we already know how many moles of the limiting reactant we have (0.3), we can easily calculate how much of the product we will produc...
by NRobbins_1K
Mon Oct 07, 2019 4:37 pm
Forum: Empirical & Molecular Formulas
Topic: Empirical Formula Help [ENDORSED]
Replies: 7
Views: 279

Re: Empirical Formula Help [ENDORSED]

As an example to answer your question, let's say that you were asked to find the empirical formula for a compound containing 52.14% carbon, 13.2% hydrogen and 34.73% oxygen. It sounds like you know how to convert these percentages to molar amounts, so I'm going to skip that part and assume that you ...
by NRobbins_1K
Wed Oct 02, 2019 10:33 am
Forum: Molarity, Solutions, Dilutions
Topic: G.5- Mixtures and Solutions
Replies: 3
Views: 39

Re: G.5- Mixtures and Solutions

First, we find out how many moles of sodium carbonate are in 2.111 g so that we can find the molarity of the sodium carbonate solution. We divide the mass by sodium carbonate's molecular weight 2.111/106 to find that we have 0.01992 moles of sodium carbonate. To find the molarity, we divide the mole...
by NRobbins_1K
Tue Oct 01, 2019 4:40 pm
Forum: Molarity, Solutions, Dilutions
Topic: Help on G. 21
Replies: 2
Views: 65

Re: Help on G. 21

You were correct in dividing the NaCl and the KCl by the molar mass of each salt, because by doing this you were finding how many moles of the compound were in each sample. Since there is exactly one chlorine atom per molecule of each salt, you can correctly assume that the moles of NaCl dissolved =...
by NRobbins_1K
Tue Oct 01, 2019 4:23 pm
Forum: Balancing Chemical Reactions
Topic: Tips on what number to multiply the entire equation if needed
Replies: 8
Views: 240

Re: Tips on what number to multiply the entire equation if needed

For simple equations, you will usually only have one number in the denominator of your stoichiometric coefficients. Simply multiply the coefficient of every molecule in the reaction by the number in the denominator to finalize the balanced reaction. If there are multiple numbers in the denominators ...
by NRobbins_1K
Tue Oct 01, 2019 4:12 pm
Forum: Limiting Reactant Calculations
Topic: HW problem L1
Replies: 3
Views: 64

Re: HW problem L1

Since the molar ratio of the reactant to the product is 6:1 we can see that for every six moles of the reactant, we will produce one mole of the product. Therefore we can divide .3 moles by 6 to find that the reaction will produce .05 moles of product, Br2. To find the mass of .05 moles of Br2, simp...
by NRobbins_1K
Mon Sep 30, 2019 9:27 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Calculations in Two-Step Reactions
Replies: 4
Views: 165

Re: Limiting Reactant Calculations in Two-Step Reactions

@Jessica_Tran you did the problem right, but you forgot to include the H2 produced by the first stage of the reaction!
by NRobbins_1K
Mon Sep 30, 2019 9:26 pm
Forum: Limiting Reactant Calculations
Topic: Limiting Reactant Calculations in Two-Step Reactions
Replies: 4
Views: 165

Re: Limiting Reactant Calculations in Two-Step Reactions

Since the molar ratio of CH4 to H2O is 1:1, we start by seeing how many moles of CH4 we have to begin with, and the same number of moles of water will be consumed by the first reaction. To find the moles of methane (CH4) we divide the amount in grams (.036) by the molar mass of methane (16.04) and f...

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