## Search found 72 matches

Sat Dec 08, 2018 4:39 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty
Replies: 1
Views: 319

### Uncertainty

When using the uncertainty equation how do you know when to give your answer using "greater than" or "equal" sign?
Thu Dec 06, 2018 10:45 pm
Forum: Naming
Topic: Naming
Replies: 2
Views: 176

### Naming

Why do we include "bis" for oxalato for the complex [RhCl(OH)(C2O4)2]8H20 ?
Thu Dec 06, 2018 3:02 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: CO3^2-
Replies: 2
Views: 197

### CO3^2-

Why is CO3^2- both monodenate and bidentate if there's three oxygens and together they have 8 lone pairs. One double between C and O and three single bonds between C and O. So, why isn't a polydentate?
Thu Dec 06, 2018 1:20 am
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: 6C.21 (7th ed)
Replies: 1
Views: 118

### 6C.21 (7th ed)

Why is formic acid slightly stronger than acetic acid? Also, is an acid weaker if it has more H's attached?
Wed Dec 05, 2018 11:14 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: 9C.5 (7th ed)
Replies: 2
Views: 175

### 9C.5 (7th ed)

Which of the following ligands can be polydentate? If the ligand can be polydentate, give the maximum number of places on the ligand that can bind simultaneously to a single metal center: a)HN(CH2CH2NH2)2; b)CO3^2-; c)H20; d) oxalate I know polydentate means that it has more than 2 regions to form r...
Wed Dec 05, 2018 6:21 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Unidentate
Replies: 3
Views: 179

### Unidentate

How would do you identify if a molecule is unidentate or polydentate?
Sun Dec 02, 2018 9:59 pm
Forum: Lewis Acids & Bases
Topic: Amphoteric Compounds
Replies: 1
Views: 112

### Amphoteric Compounds

If you are given a chemical reaction how would you identify whether the molecule is amphoteric?
Sun Dec 02, 2018 9:55 pm
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Sigma and Pi Bonds
Replies: 6
Views: 594

### Re: Sigma and Pi Bonds

Yes, that is correct for every double bond there is one sigma and one pi bond and for every triple bond there is two pi bonds and 1 sigma bond.
Sun Dec 02, 2018 9:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Square Planar
Replies: 12
Views: 689

### Re: Square Planar

All the bond angles are equal to 90 the bond shape of two lone pairs and four bonds cancel out.
Sun Dec 02, 2018 9:52 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted Acid vs Lewis Acid
Replies: 2
Views: 182

### Bronsted Acid vs Lewis Acid

How would you identify a Lewis acid vs a Bronsted acid?
Fri Nov 30, 2018 1:27 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: H-Bonding and Dipole Dipole
Replies: 2
Views: 169

### H-Bonding and Dipole Dipole

If there is hydrogen bonding present in a molecule are there also dipole-dipole forces present?
Sat Nov 24, 2018 5:50 pm
Forum: Electronegativity
Topic: Determine Electronegativity of Molecule
Replies: 1
Views: 139

### Determine Electronegativity of Molecule

How do you know which molecule has the greatest electronegativity without doing any calculations? For example, HF or HI?
Sat Nov 24, 2018 5:48 pm
Forum: Dipole Moments
Topic: Dipole Moment
Replies: 2
Views: 207

### Dipole Moment

How do you determine which molecule has the greatest or smallest dipole moment?
Sat Nov 24, 2018 1:18 am
Forum: Hybridization
Topic: 2.45 (7th ed)
Replies: 1
Views: 119

### 2.45 (7th ed)

How come when writing the hybridization for a sigma bond between oxygen and carbon we use the notation (C2sp2,O2sp2), but when we write the notation for the oxygen lone pair we do not include the 2--which refers to oxygen being in the second row--and simply write (Osp2) for the lone pair? So, why do...
Sat Nov 17, 2018 4:36 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw and T-Shape
Replies: 1
Views: 125

### Seesaw and T-Shape

What are the bond angles for seesaw and T-shape? Various sources give different estimations but I'm not sure which is the most accurate.
Sat Nov 17, 2018 11:33 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Square Pyramidal
Replies: 2
Views: 155

### Re: Square Pyramidal

Yes, the shape is possible its electron geometry is Octahedral. The general formula would be AX5E because of the 5 bonds it forms and the one lone pair it has.
Sat Nov 17, 2018 3:36 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Sigma and Pi Bonds
Replies: 2
Views: 116

### Re: Sigma and Pi Bonds

First, you would need to have the Lewis Structure provided or draw the Lewis Structure for the molecule. Then you would look at at where the molecule forms single bonds those would be your sigma bonds and wherever it forms double bonds you would have one pi bond and one sigma bond and wherever tripl...
Sat Nov 17, 2018 2:12 am
Forum: Determining Molecular Shape (VSEPR)
Topic: Seesaw Shape
Replies: 4
Views: 210

### Seesaw Shape

Would the bond angles for the Seesaw shape be 90,120,180. If so, would all the bond angles be slightly less than that of the trigonal bipyramidal?
Fri Nov 16, 2018 3:21 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: H-Bonding
Replies: 8
Views: 367

### Re: H-Bonding

Hydrogen bonding only occurs for bonds between F,O,N.
Fri Nov 16, 2018 10:09 am
Forum: Determining Molecular Shape (VSEPR)
Topic: 2E.25 (7th ed)
Replies: 2
Views: 135

### 2E.25 (7th ed)

For the molecule CH2Cl2 if I arrange the two H's opposite of each other and the Cl's opposite of each other the dipole moments cancel out making it nonpolar, but if I don't rearrange the H's and Cl's opposite of each other it's a polar molecule. How would I know which is the correct polarity?
Fri Nov 09, 2018 10:51 am
Forum: Electronegativity
Topic: Electronegativity relationship with Polarizability
Replies: 3
Views: 330

### Re: Electronegativity relationship with Polarizability

So, for electronegativity anions with a higher electronegativity have a weaker effective nuclear charge due to the addition of shells and because those anions such as Iodine that are far away from the charge of the nucleus its much easier for them to become distorted by cations. The higher the elect...
Fri Nov 09, 2018 10:11 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: electron distortion
Replies: 4
Views: 266

### Re: electron distortion

It involves atomic radius. So you can think about it as the smaller the cation the stronger its going to be attached to the nucleus charge making it easier to take away electrons from the anion and if the cation takes away those electrons then its going to distort or mess with the structure of the a...
Fri Nov 09, 2018 10:05 am
Forum: Trends in The Periodic Table
Topic: Bond Lenghts
Replies: 7
Views: 585

### Bond Lenghts

How can you tell which molecules have a greater bond length without having its Lewis structure? I know when you have two ions you look for polarizability but what about when you have multiple elements involved?
Fri Nov 09, 2018 8:59 am
Forum: Bond Lengths & Energies
Topic: 2D.3 (7th ed)
Replies: 2
Views: 98

### 2D.3 (7th ed)

Why does BaBr2 have more ionic bonds than BeBr2?
Sun Nov 04, 2018 12:43 am
Forum: Resonance Structures
Topic: 2B.15 (7th ed) [ENDORSED]
Replies: 1
Views: 138

### 2B.15 (7th ed)[ENDORSED]

Draw the Lewis structures that contribute to the resonance hybrid of nitryl chloride, ClNO2 (N is the central atom). How come the solution to this problem doesn't show two double bonds between both oxygens and nitrogen? Is it not allowed? Can someone please explain when we are allowed to make multip...
Fri Nov 02, 2018 9:53 pm
Forum: Trends in The Periodic Table
Topic: 1F.11 (7th ed)
Replies: 1
Views: 168

### 1F.11 (7th ed)

Which element of each of the following pairs has the higher electron affinity.
a. Te or I
b. Be or Mg
c. O or S
d. Ga or In

Why are b and d both equal in energy? And for part c sulfur has a greater affinity even though its down the group meaning effective nuclear charge decreases?
Fri Nov 02, 2018 8:41 pm
Forum: Resonance Structures
Topic: 2B.19 (7th ed)
Replies: 2
Views: 127

### 2B.19 (7th ed)

Draw the Lewis structure and determine the formal charge on each atom.

So far CN- how come we couldn't have done 5 bonds with 1 lone pair on nitrogen. The solution shows 3 bonds and 1 lone pair on C and 1 lone pair on nitrogen but I don't understand why they have that structure?
Fri Nov 02, 2018 7:59 pm
Forum: Resonance Structures
Topic: Determine Number of Resonance Structures
Replies: 2
Views: 210

### Determine Number of Resonance Structures

How do we determine how many resonance structures there are for a molecule?
Fri Nov 02, 2018 6:39 pm
Forum: Photoelectric Effect
Topic: Photoelectric Experiment - Chem Test 2
Replies: 3
Views: 315

### Re: Photoelectric Experiment - Chem Test 2

Was the kinetic energy 5.5x^10^6?
Fri Nov 02, 2018 6:30 pm
Forum: SI Units, Unit Conversions
Topic: Molar Mass to Kg
Replies: 6
Views: 1036

### Molar Mass to Kg

How would we convert from g/mol to kg if the element is unknown meaning we don't know the mass of the element?
Fri Nov 02, 2018 4:33 pm
Forum: Properties of Electrons
Topic: Test 2
Replies: 1
Views: 327

### Test 2

How would we convert 5 mol of electrons to kg? Would we simply multiply 5 mol by avogadro's number?
Thu Nov 01, 2018 7:11 pm
Forum: Ionic & Covalent Bonds
Topic: 2A.15 (7th Ed)
Replies: 1
Views: 116

### 2A.15 (7th Ed)

Write the most likely charge for the ions formed each of the following elements.
How would I determine how many electrons Te would gain or lose if it's a metalloid?
Sun Oct 28, 2018 10:44 pm
Forum: Quantum Numbers and The H-Atom
Topic: Degeneracy
Replies: 3
Views: 205

### Re: Degeneracy

It means that all orbitals have the same energy. So the three orbitals in 2p are degenerate because they have the same energy.
Sun Oct 28, 2018 6:44 pm
Forum: Lewis Structures
Topic: Lewis Structure
Replies: 2
Views: 96

### Lewis Structure

How do you know which Lewis structure is the most stable?
Fri Oct 26, 2018 12:34 am
Forum: DeBroglie Equation
Topic: Measurable wavelength properties
Replies: 5
Views: 340

### Re: Measurable wavelength properties

The object will not have wavelike properties for objects such as 10^-34 because they are to big too big. I believe the maximum it can be is 10^-18 for it to have wavelength properties.
Thu Oct 25, 2018 11:43 am
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Module Question 20
Replies: 4
Views: 364

### Module Question 20

20. Use the above uncertainty in velocity to calculate the electron's uncertainty in kinetic energy. Then calculate the uncertainty in kinetic energy per mole of electrons (that is, per mole of hydrogen atoms). Comment on your value. I calculated the uncertainty in kinetic energy, but how do we calc...
Sat Oct 20, 2018 5:43 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Schrodinger's Wave Function
Replies: 10
Views: 465

### Schrodinger's Wave Function

Are we expected to apply Schrodinger's wave function equation for the test? If so, under what scenarios?
Sat Oct 20, 2018 5:35 pm
Forum: Quantum Numbers and The H-Atom
Topic: Nodes
Replies: 1
Views: 133

### Nodes

How does the experiment on atomic spectra where we discussed the Balmer and Lyman Series relate to the nodes of an orbit? I know it has to do with the energy levels but can someone give a detailed explanation. Thank you.
Thu Oct 18, 2018 9:22 pm
Forum: DeBroglie Equation
Topic: De Broglie
Replies: 12
Views: 846

### De Broglie

When do you know when to use the De Broglie equation?
Thu Oct 18, 2018 9:20 pm
Forum: Photoelectric Effect
Topic: 1B.7
Replies: 3
Views: 107

### Re: 1B.7

Where did you get the energy of sodium from?
Thu Oct 18, 2018 8:21 pm
Forum: Photoelectric Effect
Topic: 1B.7
Replies: 3
Views: 107

### 1B.7

Sodium vapor lamps, used for public lighting, emit yellow light of wavelength 589nm. How much energy is emitted by: a) an excited sodium atom when it generates a photon b) 5.00 mg of sodium atoms emitting light at this wavelength c) 1.00 mol of sodium atoms emitting light at this wavelength So part ...
Tue Oct 16, 2018 12:34 am
Forum: Einstein Equation
Topic: Calculate Number of Photons
Replies: 3
Views: 127

### Re: Calculate Number of Photons

Why do we have to divide energy by the energy of a photon? I know its to calculate the number of photons, but how did you know we had to divide?
Tue Oct 16, 2018 12:18 am
Forum: Einstein Equation
Topic: Calculate Number of Photons
Replies: 3
Views: 127

### Calculate Number of Photons

Question 1B.9:A lamp rated at 32W emits violet light of wavelength 420nm. How many photons of violet light can the lamp generate in 2 seconds?

So I calculated the energy per photon which turned out to 4.7x10^-19 J, but I'm not sure what are the next steps I need to take to find the number of photons.
Sat Oct 13, 2018 10:35 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Bohr Frequency
Replies: 2
Views: 140

### Bohr Frequency

When talking about the incoming light that matches the energy difference are the words light and frequency used interchangeably?
Sat Oct 13, 2018 5:53 pm
Forum: Properties of Electrons
Topic: Module Photoelectric Effect
Replies: 2
Views: 114

### Re: Module Photoelectric Effect

I realized I didn't post the full question. Here's the entire question.

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.
Part B: How much energy is required to remove an electron from one sodium atom?
Sat Oct 13, 2018 4:55 pm
Forum: Properties of Electrons
Topic: Module Photoelectric Effect
Replies: 2
Views: 114

### Module Photoelectric Effect

Hi,
For this problem I'm not sure where to start would we use the mass of sodium and convert to moles? If someone could explain the process step by step that would help.

28. B. How much energy is required to remove an electron from one sodium atom?
Sat Oct 13, 2018 10:24 am
Forum: Limiting Reactant Calculations
Topic: Formula Units and Molecules
Replies: 2
Views: 525

### Re: Formula Units and Molecules

Molecules and formula units essentially you could think about like the number of atoms. Formula units are used for ionic compounds whereas molecules are used for a compound with more than one element so if asked to solve number of formula units its the same process as solving for number of atoms.
Thu Oct 11, 2018 9:40 pm
Forum: Properties of Light
Topic: Calculate values of n
Replies: 2
Views: 59

### Calculate values of n

Hey guys, So I calculated the wavelength, but I don't know where to go from there. Problem 1A.15 7th edition. In the ultraviolet spectrum of atomic hydrogen, a line is observed at 102.6 nm. Determine the values of n for the initial and final energy levels of the electron during the emission of energ...
Tue Oct 09, 2018 11:20 pm
Forum: Properties of Light
Topic: Photons
Replies: 4
Views: 93

### Photons

Does increasing the intensity affect the number of photons that are emitted? Or is it increasing the frequency that affects the number of photons emitted?
Tue Oct 09, 2018 11:18 pm
Forum: Properties of Light
Topic: Light
Replies: 9
Views: 627

### Light

How does amplitude affect frequency? And what is the relationship between the wavelength and frequency?
Fri Oct 05, 2018 10:28 pm
Forum: Limiting Reactant Calculations
Topic: M.9
Replies: 2
Views: 95

### Re: M.9

That make sense! Thank you!
Fri Oct 05, 2018 10:04 pm
Forum: Limiting Reactant Calculations
Topic: M.9
Replies: 2
Views: 95

### M.9

Copper (II) nitrate reacts with sodium hydroxide to produce a precipitate of light blue copper(II) hydroxide. (a) Write the net ionic equation for the reaction. (b) Calculate the maximum mass of copper(II) hydroxide that can be formed when 2.00 g of sodium hydroxide is added to 80.0 mL of 0.500 M Cu...
Thu Oct 04, 2018 11:18 pm
Forum: Limiting Reactant Calculations
Topic: Volume of Solution
Replies: 2
Views: 154

### Volume of Solution

A student prepared a solution of sodium carbonate by adding 2.111g of the solid to a 250.0mL volumetric flask and adding water to the mark. Some of this solution was transferred to a buret. What volume of solution should the student transfer into a flask to obtain a. 2.15 mmol Na+ So I converted to ...
Thu Oct 04, 2018 10:44 pm
Forum: Limiting Reactant Calculations
Topic: Calculating Maximum Mass
Replies: 5
Views: 896

### Re: Calculating Maximum Mass

I made a typo I did get Cu(OH)2. But I'm confused on part b.
Thu Oct 04, 2018 10:42 pm
Forum: Molarity, Solutions, Dilutions
Topic: HW L1
Replies: 3
Views: 116

### Re: HW L1

For my answer I got 0.05 mol Br2. How I solved it was by using a mole to mole ratio from the balanced equation.
Thu Oct 04, 2018 10:39 pm
Forum: Limiting Reactant Calculations
Topic: Calculating Maximum Mass
Replies: 5
Views: 896

### Calculating Maximum Mass

Problem M.9 Copper (II) nitrate reacts with sodium hydroxide to produce a precipate of light blue copper (II) hydroxide. (a) Write the net ionic equation for the reaction. (b) Calculate the maximum mass of copper (II) hydroxide that can be formed when 2.00 g of sodium hydroxide is added to 80.0mL of...
Thu Oct 04, 2018 10:12 pm
Forum: Empirical & Molecular Formulas
Topic: Post-Module Assessment Q22
Replies: 3
Views: 191

### Re: Post-Module Assessment Q22

After calculating the empirical formula you divide the molar mass of the compound by the empirical formula.
Thu Oct 04, 2018 10:10 pm
Forum: Empirical & Molecular Formulas
Topic: Post-Module Assessment Q22
Replies: 3
Views: 191

### Re: Post-Module Assessment Q22

You would divide by the smallest moles each element. Once you do so, you'll have to make sure they are whole numbers which could mean you have to multiply by a number that will give you whole numbers.
Thu Oct 04, 2018 10:08 pm
Forum: Limiting Reactant Calculations
Topic: Determining Limiting Reagent [ENDORSED]
Replies: 2
Views: 251

### Determining Limiting Reagent[ENDORSED]

How do we determine which reactant is the limiting reagent and excess from the balanced equation? For instance, if I was given something as 2A+3B yield 1C.
Thu Oct 04, 2018 2:20 pm
Forum: Balancing Chemical Reactions
Topic: H3, coefficients
Replies: 7
Views: 352

### Re: H3, coefficients

I feel as long as your final answer follows the Law of Conservation of Mass and you have the same amount of products and reactants it should be valid, but again don't quote me on that.
Wed Oct 03, 2018 10:02 pm
Forum: SI Units, Unit Conversions
Topic: Formula Units??
Replies: 3
Views: 285

### Re: Formula Units??

Formula units is the same process as solving for molecules or atoms. For an element it is referred to as atoms, compound it is referred to as molecule, and for an ionic compound it is referred to as formula units.
Wed Oct 03, 2018 6:56 pm
Forum: Limiting Reactant Calculations
Topic: Limiting reactants product of moles
Replies: 4
Views: 231

### Re: Limiting reactants product of moles

So first you would want to calculate the moles of reactants. Once you have the moles you can use the molar ratio from the balanced equation to see how many moles are required and figure which is your excess and limiting. Once you know that you can do a mole to mole ratio and mole to mass ratio. Hope...
Wed Oct 03, 2018 6:52 pm
Forum: Balancing Chemical Reactions
Topic: Combustion
Replies: 6
Views: 364

### Re: Combustion

A combustion reaction will always yield the products of CO2 and H2O.
Tue Oct 02, 2018 11:03 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: stoichiometric terminology
Replies: 3
Views: 205

### Re: stoichiometric terminology

Another way of thinking of formula units is simply number of atoms the difference is for an element it is referred to as atoms, but for an ionic compound it is referred to as formula units. They both measure the moles per mass.
Tue Oct 02, 2018 11:03 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: stoichiometric terminology
Replies: 3
Views: 205

### Re: stoichiometric terminology

Another way of thinking of formula units is simply number of atoms the difference is for an element it is referred to as atoms, but for an ionic compound it is referred to as formula units. They both measure the moles per mass.
Tue Oct 02, 2018 7:44 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: number of moles, molecules, and formula units?
Replies: 3
Views: 170

### Re: number of moles, molecules, and formula units?

An elements mass per mole is measured in atoms. A molecule is measured in mole per molecules. Formula units simply refers to a compound with a metal and nonmetal (ionic) which is then referred to formula units.
Mon Oct 01, 2018 7:31 pm
Forum: Balancing Chemical Reactions
Topic: Balance Equation L.35
Replies: 6
Views: 735

### Balance Equation L.35

Hi, so for this problem after we balance each chemical equation how do we come up with the final balanced chemical equation? Sodium bromide, NaBr, which is used to produce AgBr for use in photographic film, can itself be prepared as follows. FeBr+Br2 ---> FeBr2 FeBr2+Br2---> Fe3Br8 Fe3Br8+Na2CO3-->N...
Mon Oct 01, 2018 4:00 pm
Forum: SI Units, Unit Conversions
Topic: Naming Compounds
Replies: 8
Views: 344

### Re: Naming Compounds

As to there being a short cut I'm not sure, but I would say memorizing the most common polyatomic ions.
Mon Oct 01, 2018 3:57 pm
Forum: Limiting Reactant Calculations
Topic: Percent yield
Replies: 10
Views: 650

### Re: Percent yield

The theoretical yield is found once you have done the limiting reagent calculations. So once you know which is the limiting reagent the theoretical yield is calculated by multiplying molar mass and number of moles of whichever product you are solving for.
Sat Sep 29, 2018 10:46 pm
Forum: Limiting Reactant Calculations
Topic: Calculating Required Moles
Replies: 2
Views: 155

### Calculating Required Moles

For the following equation, determine the limiting reagent if 21.4 g NH3 is reacted with 42.5 g of O2.

4NH3(g) + 5O2(g) ---> 4NO(g) + 6H2O(g)

So I calculated 0.266 mol O2 and 0.315 mol NH3. My question is if it is a 4 to 5 ratio how do we calculate the required moles?
Sat Sep 29, 2018 6:00 pm
Forum: Empirical & Molecular Formulas
Topic: Percent Composition
Replies: 5
Views: 389

### Re: Percent Composition

Okay, thank you. Also, for part b why is the mass percentage of oxygen 4 sig figs? Since the smallest number of sig figs throughout the calculation I believe is 5.
Fri Sep 28, 2018 7:46 pm
Forum: Empirical & Molecular Formulas
Topic: Percent Composition
Replies: 5
Views: 389

### Percent Composition

I was browsing through Fundamentals F and I came across this question: (a) Write the formula for nitric acid. (b) Without doing a calculation, estimate which element in nitric acid occurs with the greatest mass percentage. So for part b, do we just assume that nitric acid (HNO3 I believe is the form...