## Search found 48 matches

Sun Dec 08, 2019 9:48 am
Forum: Biological Examples
Topic: Formulas for acid rain
Replies: 2
Views: 106

### Formulas for acid rain

What are the formulas we have to know for acid rain?
Sat Dec 07, 2019 11:03 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: 6B.5 Part C
Replies: 1
Views: 50

### Re: 6B.5 Part C

The Ba ion usually has a positive charge of +2 (Ba2+) because it becomes more stable when losing 2 electrons. OH- always has a negative charge. Therefore, 2 OH- are bonded to Ba2+ in order for the compound to be neutral.
Sat Dec 07, 2019 10:58 pm
Forum: Naming
Topic: polydentate
Replies: 1
Views: 42

### polydentate

Will all polydentate ligands be named with the prefixes bis, tris, tetrakis, even if they're acting as a monodentate ligands in certain situations?
Sat Dec 07, 2019 10:53 pm
Forum: DeBroglie Equation
Topic: Identifying the need to use DeBroglie Equation
Replies: 3
Views: 148

### Re: Identifying the need to use DeBroglie Equation

You will use the De Broglie equation in most quantum questions when the question asks for either the momentum, frequency, or wavelength of an electron. If you given any 2 of these variables, you can find the other using wavelength=h/mv. You can also find the energy of an electron using this equation...
Sat Dec 07, 2019 10:47 pm
Forum: Calculating the pH of Salt Solutions
Topic: weak acid/base and pH
Replies: 2
Views: 98

### Re: weak acid/base and pH

Yes, because acids have pH less than 7 and bases have pH greater than 7.
Sat Dec 07, 2019 10:36 pm
Forum: Calculating the pH of Salt Solutions
Topic: 6D.11 (d)
Replies: 2
Views: 104

### 6D.11 (d)

HW question 6D.11 (d) asks whether the solution of KBr has a pH greater than, equal to, or less than 7. Why is the aqueous solution of KBr equal to 7? How would I write a chemical equation to show this?
Sat Dec 07, 2019 8:33 pm
Forum: Naming
Topic: Abbreviations
Replies: 6
Views: 166

### Re: Abbreviations

I'm pretty sure we can use abbreviations for (en) and (edta). I'm not sure about oxalato.
Sat Dec 07, 2019 1:21 pm
Forum: Hybridization
Topic: 2sp2 vs sp2
Replies: 3
Views: 95

### 2sp2 vs sp2

What does it mean when there's a 2 in front of the hybridization? For example, in question 17 of marshmallow many of the sigma bonds have C2sp2 or N2sp hybridizations.
Thu Dec 05, 2019 4:19 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Naming acids
Replies: 2
Views: 71

### Naming acids

Question J.23 asks to name the acid formed when (a) CO2 and (b) SO3 react with water. Should we know how to name acidic compounds? I don't remember learning this.
Wed Dec 04, 2019 10:08 pm
Forum: Naming
Topic: Parentheses
Replies: 1
Views: 37

### Parentheses

Why is "diaqua" in parentheses in sodium bisoxalato(diaqua)ferrate (III)?
Wed Dec 04, 2019 7:16 pm
Forum: Naming
Topic: "Ferrate"
Replies: 14
Views: 838

### "Ferrate"

When naming the complex ion (Fe(CN)6)4-, why is iron represented as "ferrate"? Is this just something I have to memorize?
Sun Dec 01, 2019 12:08 pm
Forum: Naming
Topic: Coordination Compounds Formula
Replies: 1
Views: 39

### Re: Coordination Compounds Formula

Yes, anion ligands come before neutral ligands. If there's more than one anion or neutral ligand, they're written in alphabetical order.
Sun Dec 01, 2019 12:03 pm
Forum: Administrative Questions and Class Announcements
Topic: Asterisks on Chemistry Community
Replies: 1
Views: 46

### Re: Asterisks on Chemistry Community

I think this means that these topics won't be covered on exams.
Sun Dec 01, 2019 11:59 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Midterm Problem
Replies: 4
Views: 188

### Re: Midterm Problem

This used to confuse me too. We know we're supposed to use Ca2+ and Mg2+ because these are the most common ions of these elements. Ca and Mg both have 2 valence electrons, so they often donate 2 electrons and become 2+ ions. The question asks for the ground state configuration of the ION and not the...
Sun Dec 01, 2019 11:46 am
Forum: Amphoteric Compounds
Topic: Identifying Them?
Replies: 12
Views: 202

### Re: Identifying Them?

You can identify an amphoteric compound by seeing if it would be able to both accept and donate hydrogen atoms.
Sat Nov 30, 2019 7:33 pm
Forum: Naming
Topic: Coordination compounds vs complexes
Replies: 2
Views: 40

### Coordination compounds vs complexes

Is there a difference between complexes and coordination compounds? The textbook uses these 2 terms often and I'm wondering if the have the exact same meaning.
Thu Nov 21, 2019 1:37 pm
Forum: Hybridization
Topic: Hybridization with lone pairs on central atom
Replies: 6
Views: 104

### Hybridization with lone pairs on central atom

Can hybridization be done for atoms with shapes that aren't linear, trigonal planar, tetrahedral, trigonal bipyramidal, or octahedral? For example, can atoms with bent, seesaw, etc. shapes have a hybridization? If not, why?
Sun Nov 17, 2019 2:43 pm
Forum: Hybridization
Topic: Test 2 Topics
Replies: 11
Views: 167

### Re: Test 2 Topics

This is what one of the TA's said: - Use VSEPR model to determine the shape of inorganic, organic, and small biological molecules, cations, and anions - Use bond dipole moments and shape to determine if a molecule is polar or non-polar - Use shape and polar or non-polar properties, identify intermol...
Sun Nov 17, 2019 2:39 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Equatorial vs Axial
Replies: 1
Views: 39

### Equatorial vs Axial

I don't understand the difference between equatorial and axial angles. If the repulsion between electrons is equal, why aren't all the angles equal in certain structures? (like trigonal bipyramidal)
Sun Nov 17, 2019 2:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Electron Density
Replies: 2
Views: 31

### Re: Electron Density

Yes, a single electron counts as a region of electron density just as a lone pair would.
Sun Nov 17, 2019 1:49 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Question 2E.11) d
Replies: 1
Views: 27

### Question 2E.11) d

Question 2E.11 asks for the VSEPR model, shape, and formula for xenon trioxide. I know the formula is AX3E and the shape is trigonal pyramidal, but I don't understand why the bonds between xenon and oxygen are all double bonds in the structure. When I drew the structure, I found that there were 26 e...
Sat Nov 16, 2019 7:26 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs and angles
Replies: 1
Views: 38

### Lone pairs and angles

How can you find the bond angles of molecules with lone pairs? Are they always smaller than the original angles?
Sun Nov 10, 2019 4:53 pm
Forum: Octet Exceptions
Topic: Antioxidants
Replies: 9
Views: 296

### Antioxidants

How do antioxidants react with radicals? What does this look like on a chemical level?
Sun Nov 10, 2019 4:49 pm
Forum: Octet Exceptions
Topic: Incomplete octets
Replies: 3
Views: 133

### Incomplete octets

Are incomplete octets common? How do we know if an atom can have an incomplete octet? I don't understand this concept.
Sun Nov 10, 2019 4:44 pm
Forum: Electronegativity
Topic: Electronegativity Exceptions
Replies: 3
Views: 37

### Re: Electronegativity Exceptions

The only exceptions are noble gases because they have a complete valence shell and don't tend to accept electrons.
Sun Nov 10, 2019 3:47 pm
Forum: Octet Exceptions
Topic: Elements like Xenon
Replies: 1
Views: 56

### Re: Elements like Xenon

Yes, I believe 12 is the limit.
Sun Nov 03, 2019 10:17 pm
Forum: Ionic & Covalent Bonds
Topic: Valence electrons of transition metals
Replies: 2
Views: 71

### Valence electrons of transition metals

Is there an easy way to find the number of valence electrons for transition metals on the periodic table? Is there some type of pattern, like with elements in the main groups?
Sun Nov 03, 2019 4:48 pm
Forum: Quantum Numbers and The H-Atom
Topic: Highest energy level
Replies: 1
Views: 45

### Highest energy level

Page 31 of the textbook explains how the highest energy level is 0, but I don't understand what this means. If 0 is the point when the electron is escaping from the nucleus, how could this be the highest energy level?
Sun Nov 03, 2019 4:41 pm
Forum: Photoelectric Effect
Topic: Photoelectric Effect Equation
Replies: 3
Views: 70

### Re: Photoelectric Effect Equation

There's 2 equations we use for the photoelectric effect. E= hv (where E: photon energy, h: Planck's constant= 6.63x10^-34, and v= frequency) This equation can also be written as E= hc/wavelength (where c: speed of light= 3.00x10^8) We can use this equation if we're given (1) the energy of the photon...
Sun Nov 03, 2019 4:28 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Aufbau Principle
Replies: 2
Views: 39

### Re: Aufbau Principle

The aufbau principle states that electrons will fill lower energy levels before moving to higher energy orbitals, but the rules are all related. The aufbau principle takes into account the Pauli exclusion principle and Hund's rule to explain the building-up of electron configuration. You could think...
Sun Nov 03, 2019 11:37 am
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Order of removing electrons
Replies: 4
Views: 64

### Order of removing electrons

Problem 1E.17 states: For each of the following ground-state atoms, predict the type of orbital from which an electron will be removed to form the +1 ion: (a) Ge; (b) Mn; (c) Ba I don't understand the answer to (b). The solutions manual says it's 4s, but I thought it was 3d because 3d is filled afte...
Sat Nov 02, 2019 10:28 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Coulombic potential energy
Replies: 3
Views: 190

### Coulombic potential energy

1E.3 asks (a) Write an expression for the total coulomb potential energy for a lithium atom. (b) What does each individual term represent? I'm not sure how to answer this question because I don't understand the coulomb potential energy expression. The textbook expression looks different than the one...
Thu Oct 24, 2019 1:38 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: HW question
Replies: 3
Views: 82

### HW question

1B.27 states: A bowling ball of mass 8 kg is rolled down a bowling alley lane at 5.00+/-5.00 m.s^-1. What is the minimum uncertainty in its position. I understand how to solve this problem using Heisenberg's uncertainty equation, but I don't understand why delta V is 5.00 m.s^-1. Shouldn't it be 10 ...
Sun Oct 20, 2019 4:46 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty value
Replies: 4
Views: 50

### Re: Uncertainty value

I'm pretty sure the uncertainty is 10 mm.
Sun Oct 20, 2019 4:41 pm
Forum: DeBroglie Equation
Topic: Units for mass
Replies: 4
Views: 84

### Units for mass

I've noticed that in the De Broglie and Heisenberg uncertainty principle problems, we use kg as the basic unit for mass instead of g. This confused me at first because I thought we should always convert kilos to the base unit (grams, meters, etc.). Are kilograms always used as the base unit for thes...
Sun Oct 20, 2019 2:23 pm
Forum: DeBroglie Equation
Topic: Wavelike properties of protons
Replies: 2
Views: 51

### Wavelike properties of protons

I know electrons have wavelike properties, but do protons and neutrons have wavelike properties as well?
Sun Oct 20, 2019 2:08 pm
Forum: DeBroglie Equation
Topic: Module Question 35
Replies: 1
Views: 52

### Module Question 35

Question 35 on the module says: Calculate the wavelength of a 275 kg single-seat electric car traveling at a speed of 125 km.hr-1. Do electric cars have wavelike properties? I've done this problem many times and keep getting the wrong answer. I always get 1.57x10^-39. What am I doing wrong? This isn...
Sat Oct 19, 2019 3:15 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Frequencies
Replies: 7
Views: 211

### Frequencies

Some module and homework questions ask which region of the electromagnetic spectrum certain wavelengths or frequencies correspond too. Are we supposed to memorize the frequencies or wavelengths of each type of light?
Sun Oct 13, 2019 3:41 pm
Forum: Properties of Light
Topic: Wave vs particle properties
Replies: 4
Views: 78

### Wave vs particle properties

I'm, having a hard time understanding how light can have both wave and particle properties. Do both of these properties exist at the same time? If anybody has a good visual way of thinking about it that would be super helpful.
Sun Oct 13, 2019 3:37 pm
Forum: Einstein Equation
Topic: 1B.15 c)
Replies: 3
Views: 118

### Re: 1B.15 c)

The ejected electron is the electron that is released from the metallic surface. The UV radiation is the source of light that caused the ejection of the electron. In order to solve for the wavelength of the emitted electron, find the kinetic energy (KE=1/2mv^2) and use this energy in the equation E=...
Sun Oct 13, 2019 3:17 pm
Forum: Properties of Electrons
Topic: Mass of Electrons
Replies: 6
Views: 59

### Mass of Electrons

Do electrons vary in mass or is it always the same?
Sat Oct 12, 2019 11:02 pm
Forum: Photoelectric Effect
Topic: Question from module
Replies: 5
Views: 76

### Question from module

If a problem gives me only the velocity of the ejected electron and the work function for the metal, how do I find the kinetic energy? I can't figure out how to do it without needing the mass of the electron or the frequency of the incoming photon. This is the problem: Light hits a sodium metal surf...
Tue Oct 08, 2019 1:04 pm
Forum: Balancing Chemical Reactions
Replies: 5
Views: 125

Why is calcium hydroxide written as Ca(OH)2 and not just CaOH? This comes up in problem H.7
Sun Oct 06, 2019 4:15 pm
Forum: Balancing Chemical Reactions
Topic: Naming compounds
Replies: 2
Views: 70

### Naming compounds

Should we know how to name compounds at this point? I notice that a lot of question ask to write the chemical formula from the compound names and I’m just wondering if we should know how to do it the other way around.
Thu Oct 03, 2019 3:57 pm
Forum: Balancing Chemical Reactions
Topic: Confusion on H.3
Replies: 2
Views: 106

### Re: Confusion on H.3

Yes, your equation is balanced but it doesn’t represent the amount of reactants and products in the boxes. In the first box there are 4 H20 molecules and 2 SiH4 molecules. In the second box there are 2 SiO2 molecules and 8 H2 molecules. Therefore, the equation that’s both balanced and represents the...
Thu Oct 03, 2019 3:40 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Fundamentals E1
Replies: 4
Views: 140

### Re: Fundamentals E1

The radius is used to find the denominator of the atoms. Then if you multiply the denominator by the amount of atoms, you find the length of the fiber.
Thu Oct 03, 2019 3:32 pm
Forum: SI Units, Unit Conversions
Topic: Formula units vs molecule
Replies: 7
Views: 169

### Formula units vs molecule

What are formula units? Can a formula unit be the same thing as a molecule or atom? (E.21 and E.25 ask about this)
Tue Oct 01, 2019 1:41 pm
Forum: SI Units, Unit Conversions
Topic: Homework Q about finding the sulfide of a metal
Replies: 2
Views: 74

### Homework Q about finding the sulfide of a metal

Question E.15 asks to find the molar mass of the sulfide of M(OH)2, but I don’t understand how to derive a sulfide from this molecule and I’m confused by the wording. First, is sulfide just sulfur attached to a molecule? Second, is the metal the question asks about represented by M in the given mole...