## Search found 64 matches

Thu Mar 14, 2019 12:08 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Reduction of Oxygen half reaction?
Replies: 1
Views: 76

### Re: Reduction of Oxygen half reaction?

For the anode (left half of the cell diagram), oxygen is oxidized. So H20 -> H+ + e- + O2. For the cathode (right half of the cell diagram), oxygen is reduced. So 02 + e- -> OH-.+ H20.
Thu Mar 14, 2019 12:03 am
Forum: General Rate Laws
Topic: Problem 7A. 3 7th edition
Replies: 3
Views: 100

### Re: Problem 7A. 3 7th edition

The unique reaction rate is equal to -1/a of the reaction rate of O2. So, given the unique reaction rate = 0.44, then 0.44 = -1/3 (rate of O2). So you would multiply both sides by 3, which gives you 1.3 for the rate of O2.
Wed Mar 13, 2019 11:59 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium constants with partial pressures and concentrations?
Replies: 2
Views: 104

### Re: Equilibrium constants with partial pressures and concentrations?

The equilibrium constant includes both gases and aqueous species.
Wed Mar 13, 2019 11:58 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Thermodynamics learning outcome
Replies: 1
Views: 220

### Re: Thermodynamics learning outcome

This is refereeing to delta S surrounding is equal to negative delta H divided by temperature.
Wed Mar 13, 2019 11:57 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Calomel Electrode
Replies: 1
Views: 78

### Re: Calomel Electrode

Wed Mar 13, 2019 11:55 pm
Forum: General Rate Laws
Topic: reaction order and reaction quotient
Replies: 1
Views: 77

### Re: reaction order and reaction quotient

When determining the rate of a reaction, the concentration of the reactants is raised to the power of the reaction order.
Wed Mar 13, 2019 11:49 pm
Forum: General Rate Laws
Topic: 7th edition 7B.17
Replies: 1
Views: 98

### Re: 7th edition 7B.17

B forms twice as fast as A is depleted. For 0.19M of B to form, 1/2 of that is lost form A. So the concentration of A is 0.15M - 1/2(0.19M).
Wed Mar 13, 2019 11:44 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb calorimeter
Replies: 6
Views: 441

### Re: Bomb calorimeter

In a regular calorimeter, the reaction takes place in the water. In a bomb calorimeter, the reaction takes place in a sealed metal container.
Wed Mar 13, 2019 11:38 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: ΔG equation
Replies: 1
Views: 87

### Re: ΔG equation

Wed Mar 13, 2019 11:30 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Concentration cell
Replies: 1
Views: 101

### Re: Concentration cell

Due to the Nernst equation, Ecell > 0 when Q is < 0, so the concentration of the cathode will be greater than the concentration of the anode because Q = concentration of left (anode) divided by concentration of right (cathode).
Wed Mar 13, 2019 11:27 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: exercise 15.17
Replies: 1
Views: 257

### Re: exercise 15.17

The reaction rate is the change in concentration of one of the reactants or products at a selected stage of the reaction divided by the time interval over which the change takes place. The unique average rate of the reaction is the average rate divided by the stoichiometric coefficients, so the uniq...
Wed Mar 13, 2019 11:20 pm
Forum: Balancing Redox Reactions
Topic: HW problem
Replies: 2
Views: 110

### Re: HW problem

C is oxidized because its oxidation state in C2H5OH is -2 and its oxidation state in C2H4) is -1. So its oxidation number decreases which means it was oxidized because it lost 1 electron.
Thu Mar 07, 2019 12:29 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Ka vs K
Replies: 1
Views: 96

### Ka vs K

For problem 6.57 in the 7th edition, why is the value of Ka for HF the square root of K?
Thu Feb 28, 2019 6:46 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: "Strongly oxidizing"
Replies: 5
Views: 236

### Re: "Strongly oxidizing"

It means that Cu+ is a stronger oxidizing agent than H+.
Thu Feb 28, 2019 6:42 am
Forum: General Science Questions
Topic: Test 2 7th edition book
Replies: 1
Views: 318

### Re: Test 2 7th edition book

For outline 4, it covers 6K, 6L, and 6M.
Thu Feb 28, 2019 6:41 am
Forum: Balancing Redox Reactions
Topic: Oxidation state
Replies: 2
Views: 96

### Re: Oxidation state

Yes, this is correct.
Thu Feb 28, 2019 12:55 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic Cell E not
Replies: 1
Views: 60

### Galvanic Cell E not

Does a galvanic cell always have a positive potential difference?
Wed Feb 27, 2019 6:13 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Pt (s) [ENDORSED]
Replies: 8
Views: 352

### Re: Pt (s)[ENDORSED]

Pt is included because in the cathode are two ion compounds in solution, so an inert electrode is needed.
Wed Feb 27, 2019 11:11 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: test 2
Replies: 6
Views: 183

### Re: test 2

Which topic sections will be covered on Test 2 in Focus 6?
Tue Feb 26, 2019 11:36 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Delta S Fusion
Replies: 2
Views: 287

### Delta S Fusion

How does one calculate Delta S of fusion, as in the example provided in the 7th edition 4J.1?
Wed Feb 13, 2019 11:17 am
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Change in Internal Energy
Replies: 3
Views: 170

### Re: Change in Internal Energy

The change in internal energy equals 0 when it is an isothermal process.
Wed Feb 13, 2019 11:14 am
Forum: Calculating Work of Expansion
Topic: Integrals
Replies: 4
Views: 166

### Re: Integrals

no, no calculus will be required on the exam.
Wed Feb 13, 2019 1:41 am
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Reversible Heat Transfer
Replies: 1
Views: 106

### Reversible Heat Transfer

What does it mean if the transfer of heat is reversible?
Wed Feb 13, 2019 1:28 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Entropy of Irreversible Expansion
Replies: 2
Views: 297

### Entropy of Irreversible Expansion

Why can the change in entropy that has been calculated for a reversible path be used to calculate the change in entropy of the gas when it expands irreversibly?
Wed Feb 13, 2019 1:15 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Enthalpy and Enthalpy of Formation
Replies: 1
Views: 97

### Standard Enthalpy and Enthalpy of Formation

What is the difference in units between the standard enthalpy and the enthalpy of formation?
Tue Feb 12, 2019 9:22 pm
Forum: Phase Changes & Related Calculations
Topic: Steam vs Boiling Water
Replies: 8
Views: 526

### Steam vs Boiling Water

Why does steam at 100 degrees celsius cause a worse burn than boiling water at 100 degrees celsius?
Tue Feb 12, 2019 10:43 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Temperature
Replies: 3
Views: 171

### Temperature

When converting between celsius and kelvin, what are the significant figure rules?
Sat Feb 09, 2019 4:47 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Closed, Open, and Isolated Systems
Replies: 5
Views: 203

### Closed, Open, and Isolated Systems

What is the difference between a closed, an open, and an isolated system? And what are some examples?
Tue Jan 22, 2019 4:26 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure
Replies: 8
Views: 274

### Re: Pressure

Why does a change in pressure due to an inert gas not affect the equilibrium?
Tue Jan 22, 2019 4:23 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Temperature change
Replies: 5
Views: 276

### Re: Temperature change

Why does an increase in temperature with an endothermic reaction favor the formation of products? Conversely, why does an increase in temperature with an exothermic reaction favor the formation of reactants?
Tue Jan 22, 2019 4:19 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Seventh edition 5I. 27 error?
Replies: 1
Views: 68

### Re: Seventh edition 5I. 27 error?

I also calculated it to be 4.84.
Sun Jan 13, 2019 10:50 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 7
Views: 151

### Re: Le Chatelier's Principle

A change in one of the variables that describe a system at equilibrium produces a shift in the position of the equilibrium that counteracts the effect of this change. Le Chatelier's principle describes what happens to a system when something momentarily takes it away from equilibrium. This can be us...
Sun Jan 13, 2019 10:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Le Chatelier's Principle
Replies: 2
Views: 44

### Le Chatelier's Principle

Why does K remain constant when there is a change in pressure, but K changes when there is a change in temperature.
Sun Jan 13, 2019 10:45 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Equilibrium K expression
Replies: 1
Views: 45

### Chemical Equilibrium K expression

Why are solids and liquids not included in the K expression?
Thu Dec 06, 2018 10:14 am
Forum: Dipole Moments
Topic: Dipole moment trends
Replies: 2
Views: 145

### Re: Dipole moment trends

Molecules with a dipole moment (polar molecules) dissolve in polar liquids like water.
Thu Dec 06, 2018 10:10 am
Forum: Ionic & Covalent Bonds
Topic: Net dipole
Replies: 2
Views: 186

### Re: Net dipole

ClF3 has a net dipole because the shape of the molecule is T-shape and the dipoles do not cancel each other out. BF3 does not have a net dipole because the shape is trigonal planar and the dipoles cancel each other out.
Thu Dec 06, 2018 10:09 am
Forum: Polarisability of Anions, The Polarizing Power of Cations
Topic: Polarizable
Replies: 1
Views: 326

### Re: Polarizable

Cl- < S-2 < P-3 < I- Large anions will be the most polarizable because the outer electrons are held more loosely and can be more easily distorted by the cation. Cs+ < Ba+2 < Ca+2 < Li+ Small cations will have the most polarizing power because they distort the electron cloud of the anion better due t...
Sun Dec 02, 2018 5:28 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: Induced Dipole
Replies: 1
Views: 84

### Re: Induced Dipole

An induced dipole intermolecular force results from the presence of molecules that are permanent dipoles temporarily distorting the electron charge in other nearby polar or nonpolar molecules, thereby inducing further polarization. Van der Waals forces are temporary charges on an atom because of the...
Sun Dec 02, 2018 5:23 pm
Forum: Hybridization
Topic: Hybrid Orbitals
Replies: 3
Views: 153

### Re: Hybrid Orbitals

The number of hybrid orbitals equals the number of atomic orbitals mixed. The number of hybrid orbitals is equal to the steric number which the number of sigma bonds plus number of lone pairs of electrons around the atom.
Sun Dec 02, 2018 5:19 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Definition of Ligand
Replies: 2
Views: 96

### Re: Definition of Ligand

A ligand is a molecule or ion that bonds with a metal atom. What we're focusing on is ligands bonding to central transition metals to form coordination compounds. The transition metal itself is typically not the ligand.
Mon Nov 26, 2018 11:30 am
Forum: Hybridization
Topic: Hybridization and Reactivity
Replies: 2
Views: 152

### Re: Hybridization and Reactivity

This is no ordinary triple bond as the second π interaction results from a weak interaction of sp2 hybrid orbitals lying in the plane of the ring.
The triple bond is non-linear due to the constraints of the 6-membered ring. Benzyne is strained and highly reactive.
Mon Nov 26, 2018 11:24 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: Dipole Forces
Replies: 3
Views: 153

### Re: Dipole Forces

Dipole-dipole forces result from the difference between electronegativities of the atoms in molecules. It is large enough that the electrons aren't shared equally, and yet small enough that the electrons aren't drawn exclusively to one of the atoms to form positive and negative ions. The bonds in th...
Mon Nov 26, 2018 11:10 am
Forum: Hybridization
Topic: Sigma vs Pi Bonds
Replies: 2
Views: 72

### Re: Sigma vs Pi Bonds

A sigma bond ( σ bond) is a bond formed by the overlap of orbitals in an end-to-end fashion, with the electron density concentrated between the nuclei of the bonding atoms. A pi bond ( π bond) is a bond formed by the overlap of orbitals in a side-by-side fashion with the electron density concentrate...
Sun Nov 18, 2018 9:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar molecules
Replies: 5
Views: 208

### Re: Polar molecules

Not sure if you mean NF3, but if so it is because the dipoles do not cancel each other due to the lone pair giving the shape of trigonal pyramidal. So, the N-F polar bonds make the whole molecule polar.
Sun Nov 18, 2018 9:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: T Shaped
Replies: 3
Views: 168

### Re: T Shaped

Three orbitals are arranged around the equator of the molecule with bond angles of 120 degrees. Two orbitals are arranged along the vertical axis at 90 degrees from the equatorial orbitals. The shape of the orbitals is trigonal bipyramidal. Two of the equatorial orbitals contain lone pairs of electr...
Sun Nov 18, 2018 9:27 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Distorted Bond Angles
Replies: 3
Views: 785

### Re: Distorted Bond Angles

Bond angles will deviate from their ideal values according to the rule that lone pairs repel other electrons more strongly than bonding pairs. Although lone pairs are clearly smaller than atoms, they need to be closer to the nucleus of an atom than a bonding pair. Being closer to the central atom ca...
Sun Nov 11, 2018 9:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Difference in models
Replies: 2
Views: 112

### Re: Difference in models

A molecule will be trigonal planar if it has 3 pairs of bonding electrons around the central atom. It will be trigonal pyramid if it has 3 bonding pairs of electrons and 1 lone pair of electrons around the central atom. It will be T-shape if it has 3 bonding pairs of electrons and 2 lone pairs of el...
Sun Nov 11, 2018 9:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: determining VSEPR models
Replies: 6
Views: 248

### Re: determining VSEPR models

The seesaw, tetrahedral, and square planar models differ in their number of lone pair of electrons. The tetrahedral model has 4 bonding pairs of electrons around the central atom, the seesaw has 4 bonding pairs and 1 lone pair of electrons around the central atom, and the square planar model has 4 b...
Sun Nov 11, 2018 9:46 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: London Forces
Replies: 2
Views: 98

### Re: London Forces

Because of the constant motion of the electrons, an atom or molecule can develop a temporary (instantaneous) dipole when its electrons are distributed unsymmetrically about the nucleus. A second atom or molecule, in turn, can be distorted by the appearance of the dipole in the first atom or molecule...
Sun Nov 04, 2018 10:02 pm
Forum: Lewis Structures
Topic: Lewis Structure for Ammonium chloride
Replies: 3
Views: 1374

### Re: Lewis Structure for Ammonium chloride

Ammonium chloride is a molecule joined by an ionic bond, so for the lewis structure it is represented by its respective ions NH4+ and Cl-.
Sun Nov 04, 2018 9:58 pm
Forum: Quantum Numbers and The H-Atom
Topic: Ms quantum number relevancy on the midterm
Replies: 4
Views: 230

### Re: Ms quantum number relevancy on the midterm

The Ms quantum number is important because 2 electrons in the same orbital cannot have the same the spin. They must have opposite spins. This is known as the Pauli Exclusion Principle. This allows for electrons in the same orbital to have different quantum numbers.
Sun Nov 04, 2018 9:55 pm
Forum: Electronegativity
Topic: Electronegativity
Replies: 5
Views: 199

### Re: Electronegativity

If the electronegativity difference between atoms is greater than 2, then the atoms will form an ionic bond. If the electronegativity difference between atoms is less than 1.5, then the atoms will form a covalent bond.
Sun Oct 28, 2018 11:20 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals
Replies: 3
Views: 155

### Re: Orbitals

Ms is the spin quantum number. An electron will always be either spin up or spin down. Ms will either be +1/2 or -1/2. You can choose if you want the electron to have the quantum number +1/2 or -1/2. Due to Hund's Rule, electrons in the same subshell occupy different orbitals with parallel spin. If ...
Sun Oct 28, 2018 11:14 pm
Forum: Lewis Structures
Topic: Lewis Structures
Replies: 13
Views: 387

### Re: Lewis Structures

Yes, every atom can have potentially 8 valence electrons besides H and He.
Sun Oct 28, 2018 11:05 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Orbitals
Replies: 1
Views: 143

### Re: Orbitals

The electron structure for Chromium and Copper are examples of elements with incomplete orbitals. For Chromium there is an unfilled 4s orbital with only 1 electron in it, and it has a half filled 3d orbital. For Copper there is an unfilled 4s orbital with only 1 electron in it, and it has a full 3d ...
Fri Oct 19, 2018 6:30 pm
Forum: Properties of Light
Topic: How many photons
Replies: 3
Views: 147

### Re: How many photons

First you have to calculate the energy from the lamp, which is simply 32J/s *2s = 64J (1 W = 1 J/s). Next you are given the wavelength of the light that the lamp emits. You can calculate the energy corresponding to that wavelength (using E=hc/wavelength), which would give the the energy PER PHOTON o...
Fri Oct 19, 2018 6:26 pm
Forum: Properties of Electrons
Topic: Balmer vs Lyman Series [ENDORSED]
Replies: 5
Views: 281

### Re: Balmer vs Lyman Series[ENDORSED]

For the Lyman series,which corresponds to UV light, the electrons come to rest at the energy level n=1.
For the Balmer series, which corresponds to visible light, the electrons come to rest at the energy level n=2.
Thu Oct 18, 2018 1:28 pm
Forum: Electron Configurations for Multi-Electron Atoms
Topic: Homework 1E.13 Silver
Replies: 2
Views: 53

### Homework 1E.13 Silver

Why is the ground state electron configuration for silver [Kr] 4d^10 5s^1 rather than [Kr] 4d^9 5s^2?
Sun Oct 14, 2018 9:51 pm
Forum: General Science Questions
Topic: Electron Energy Levels
Replies: 2
Views: 247

### Re: Electron Energy Levels

When an electron moves to its highest energy state, for this example let's say it came from the first energy level. When the electron moves down to a lower energy state, it will lose a certain amount of energy that is quantized to correspond to a certain energy level. If the electron moves back to t...
Sun Oct 14, 2018 9:41 pm
Forum: Properties of Electrons
Topic: Electron Question
Replies: 6
Views: 285

### Re: Electron Question

The energy of a particle is quantized, meaning it is restricted to a series of discrete values, called energy levels. According to quantum mechanics, because there are boundary conditions on wave functions and each wavelength corresponds to a different energy energy is quantized. Because an electron...
Sun Oct 14, 2018 9:35 pm
Forum: Properties of Electrons
Topic: energy transitions
Replies: 6
Views: 187

### Re: energy transitions

The orbital angular momentum quantum number (l) corresponds to the orbitals of a shell and the subshells, or group of orbital that have the sam value of l. For example, when n = 3, l can have any of the 3 values 0, 1, or 2. When l = 0, there is an s type of orbital. When l = 1, there is a p type of ...
Sun Oct 07, 2018 6:48 pm
Forum: Limiting Reactant Calculations
Topic: Reactants and Reagents
Replies: 4
Views: 197

### Re: Reactants and Reagents

Typically reagent is what you point to in the lab.

Reactant is what you point to in the balanced chemical equation.

Although, this distinction is not often made (and not that important).
Sun Oct 07, 2018 6:47 pm
Forum: Limiting Reactant Calculations
Topic: Theoretical Yield
Replies: 7
Views: 383

### Re: Theoretical Yield

Theoretical yield is the maximum yield of a product that is found through calculations. Due to side reactions, impurities, product sticking to the side of walls, human error, etc. during experiments the actual yield will be less.
Sun Oct 07, 2018 6:39 pm
Forum: Molarity, Solutions, Dilutions
Topic: Molarity Formula [ENDORSED]
Replies: 1
Views: 85

### Re: Molarity Formula[ENDORSED]

Molarity (M) = moles of solute (n) / volume of solution (v) in Liters = mol . L ^-1