## Search found 53 matches

Mon Mar 12, 2018 7:36 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: slow step
Replies: 3
Views: 226

### Re: slow step

In this class it is only possible to have single slow step mechanisms.
Mon Mar 12, 2018 7:35 pm
Forum: First Order Reactions
Topic: Pseudo First Order Reaction
Replies: 7
Views: 974

### Re: Pseudo First Order Reaction

You use a pseudo first order reaction when there is more than one reactant by making one of the reactant's concentrations very large so you can test the rate while manipulating the other reactant.
Mon Mar 12, 2018 7:30 pm
Forum: General Rate Laws
Topic: Unique Reaction Rates [ENDORSED]
Replies: 33
Views: 77892

### Re: Unique Reaction Rates[ENDORSED]

A unique rate is the same for all of the materials in the reaction (products and reactants) because it multiplies the change in substance by one over its coefficient.
Mon Mar 05, 2018 10:38 am
Forum: First Order Reactions
Topic: half life
Replies: 3
Views: 254

### Re: half life

'n' half lives refer to how many times the concentration has been halved at that point.
Mon Mar 05, 2018 10:37 am
Forum: General Rate Laws
Topic: Rate laws and integrated rate laws
Replies: 3
Views: 301

### Re: Rate laws and integrated rate laws

The differential rate law is the rate as a function of the concentration and the integrated rate law is the rate as a function of time.
Mon Mar 05, 2018 10:35 am
Forum: Balancing Redox Reactions
Topic: Basic and Acidic conditions [ENDORSED]
Replies: 11
Views: 3628

### Re: Basic and Acidic conditions[ENDORSED]

In acidic conditions the Hydrogen is balanced by H+ and H20 molecules and in basic conditions the Hydrogen is balanced by H20 and OH- molecules.
Mon Feb 26, 2018 9:25 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Cell Potential
Replies: 9
Views: 2537

### Re: Cell Potential

These equations are essentially the same so you can use them interchangeably depending on which information you have.
Mon Feb 26, 2018 9:22 pm
Forum: Balancing Redox Reactions
Topic: Half Reaction Order
Replies: 9
Views: 2160

### Re: Half Reaction Order

The oxidation half reaction includes the electrons on the right side of the arrow.
Mon Feb 26, 2018 9:20 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: swapping signs of E values
Replies: 8
Views: 919

### Re: swapping signs of E values

You swipe the sign on the anode by using the equation Ecell=Ecathode-Eanode
Thu Feb 22, 2018 2:38 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cathode vs Anode
Replies: 4
Views: 292

### Re: Cathode vs Anode

You put solids on the outside and aqueous solutions on the inside.
Thu Feb 22, 2018 2:37 pm
Forum: Balancing Redox Reactions
Topic: Gibbs free energy of half reactions
Replies: 4
Views: 330

### Re: Gibbs free energy of half reactions

Yes since G is a state property it is additive.
Thu Feb 22, 2018 2:37 pm
Forum: Balancing Redox Reactions
Topic: Writing and Balancing Half Reactions
Replies: 6
Views: 442

### Re: Writing and Balancing Half Reactions

1. Identify which species is being oxidized and which is being reduced. 2. Separate into half reactions. 3. For each one, balance the oxygen by adding H2O to the other side for each O you need. 4. Then balance the hydrogen by adding H+ to the side that needs it. 5. Make sure the reduction and oxidat...
Mon Feb 12, 2018 9:04 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Pressure
Replies: 3
Views: 239

### Re: Pressure

Work does affect pressure. W=-PdV
Mon Feb 12, 2018 9:02 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Cv vs. Cp [ENDORSED]
Replies: 13
Views: 3858

### Re: Cv vs. Cp[ENDORSED]

Cv is when the volume is constant and Cp is when the pressure is constant.
Mon Feb 12, 2018 8:59 pm
Forum: Phase Changes & Related Calculations
Topic: Reversible
Replies: 5
Views: 617

### Re: Reversible

Reversible expansion does not have a constant pressure so you use w=-nRTln(V2/V1). Irreversible expansion has a constant external pressure so you use w = -(Pex)dV
Thu Feb 08, 2018 6:09 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneity
Replies: 9
Views: 693

### Re: Spontaneity

Negative delta G signifies spontaneity while positive delta G reactions are not spontaneous.
Thu Feb 08, 2018 6:08 pm
Forum: Van't Hoff Equation
Topic: Constants
Replies: 4
Views: 412

### Re: Constants

The change in enthalpy and entropy does not change between different temperatures in this equation so they can be treated as constant.
Thu Feb 08, 2018 6:07 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Heat transfer
Replies: 7
Views: 374

### Re: Heat transfer

There is work being done because W=PdeltaV and there is a change in volume therefore there must be a change in work as long as its not free expansion.
Mon Jan 29, 2018 10:09 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Difference between systems? [ENDORSED]
Replies: 8
Views: 576

### Re: Difference between systems?[ENDORSED]

Open system - exchange energy and matter
Closed system - exchange only energy not matter
Isolated system - cannot exchange energy nor matter
Mon Jan 29, 2018 10:08 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Open System
Replies: 7
Views: 672

### Re: Open System

The three ways include adding/subtracting matter from a system, adding or removing heat energy from a system, or applying work on or from a system.
Mon Jan 29, 2018 10:07 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Relationship between entropy and volume in liquids
Replies: 5
Views: 249

### Re: Relationship between entropy and volume in liquids

If you increase the volume of any substance, the entropy also increases. However the entropy of gas is much larger than that of liquids.
Sun Jan 28, 2018 8:05 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Energy and matter?
Replies: 6
Views: 387

### Re: Energy and matter?

Yes in open systems both energy and matter can be transferred. In closed systems only energy, but not matter, can be transferred. In isolated systems neither energy nor matter can be transferred.
Sun Jan 28, 2018 8:04 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Replies: 8
Views: 3878

### Re: Isolated vs. Adiabatic system

In isolated systems, no energy is transferred to the surroundings. In an adiabatic system energy is not transferred as heat to surroundings but as work.
Sun Jan 28, 2018 8:03 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed vs. Isolated
Replies: 8
Views: 573

### Re: Closed vs. Isolated

A closed system allows energy to be transferred but not matter. An isolated system allows neither energy or matter to be transferred.
Sun Jan 21, 2018 10:13 pm
Forum: Calculating Work of Expansion
Topic: Types of Work [ENDORSED]
Replies: 3
Views: 226

### Types of Work[ENDORSED]

Is the only type of work used in this class the expansion work? There are lots of other types of work listed in a table in the textbook
Sun Jan 21, 2018 10:12 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb Calorimeters
Replies: 2
Views: 169

### Bomb Calorimeters

Can all combustion or burning reactions be treated as if they are in a bomb calorimeter?
Sun Jan 21, 2018 10:11 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 7
Views: 411

### Bond Enthalpies

Why when a bond enthalpy for a molecule is greater than that of another one is the the molecule more stable?
Wed Jan 17, 2018 3:51 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Bomb Calorimeters
Replies: 2
Views: 337

### Bomb Calorimeters

Are all bomb calorimeters isolated systems?
Wed Jan 17, 2018 3:50 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Standard Temperature
Replies: 2
Views: 127

### Standard Temperature

Why is 25 degrees C the standard temperature for reactions? Does it matter if the initial temperature is not 25degrees C?
Wed Jan 17, 2018 3:49 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Extensive vs. Intensive
Replies: 3
Views: 192

### Extensive vs. Intensive

What is the difference between extensive and intensive properties? Is this difference crucial to know for understanding the concepts?
Thu Jan 11, 2018 6:30 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Liquids and Solids
Replies: 3
Views: 248

### Liquids and Solids

If enthalpy change is in terms of gaseous substances, how do you determine the enthalpy change in the dissociation of a liquid or solid?
Thu Jan 11, 2018 6:29 pm
Forum: Phase Changes & Related Calculations
Topic: Superheating
Replies: 6
Views: 1120

### Superheating

What causes a substance to superheat or supercool? Is this common?
Thu Jan 11, 2018 6:28 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Molar Heat Capacity
Replies: 1
Views: 150

### Molar Heat Capacity

Why does molar heat capacity increase with molar complexity?
Fri Dec 08, 2017 12:33 am
Forum: Properties & Structures of Inorganic & Organic Bases
Topic: Base Strength
Replies: 2
Views: 359

### Base Strength

What makes one base stronger than another? I understand the rules for acids but the base rules seemed unclear.
Fri Dec 08, 2017 12:29 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid Strength
Replies: 5
Views: 545

### Acid Strength

Why is HF a stronger acid then HCl? I thought acid strength in this sense was determined by the electronegativity of the atom bonded to the H+ ion. Cl is more electronegative then F but on the homework it said that HF was stronger than HCl.
Tue Nov 28, 2017 10:17 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Chemical Reaction Shift
Replies: 1
Views: 149

### Chemical Reaction Shift

Since the equilibrium constant does not change, when a question asks which way the reaction shifts, is that referring to the value of Q?
Tue Nov 28, 2017 10:14 pm
Forum: Shape, Structure, Coordination Number, Ligands
Topic: Dentates
Replies: 1
Views: 206

### Dentates

How do you know what number of dentate a ligand is? Do you have to draw the lewis structure every time?
Fri Nov 24, 2017 2:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Gases
Replies: 1
Views: 180

### Gases

Why does adding inert gases not change the pressure of the gas?
Fri Nov 24, 2017 2:23 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Textbook Problem 11.47
Replies: 1
Views: 191

### Textbook Problem 11.47

I am very confused as how to find the percent decomposed of a reactant. When using the ICE table for this problem, I keep getting that PCL3 is 73% decomposed.
Thu Nov 16, 2017 6:49 pm
Forum: Hybridization
Topic: Extra P-Orbital
Replies: 1
Views: 139

### Extra P-Orbital

Why when drawing the hybridized orbitals in Aufbau format is there sometimes an extra P-orbital above the hybridized ones?
Thu Nov 16, 2017 6:47 pm
Forum: Determining Molecular Shape (VSEPR)
Replies: 4
Views: 331

How do you know where to put the radical when drawing a lewis structure?
Wed Nov 08, 2017 11:38 pm
Forum: Lewis Structures
Topic: Exceptions
Replies: 4
Views: 317

### Exceptions

Which two elements are the exceptions in the 3d sub shell?
Wed Nov 08, 2017 11:37 pm
Forum: Sigma & Pi Bonds
Topic: Bonding
Replies: 2
Views: 309

### Bonding

What is the difference between a sigma and a pi bond?
Wed Nov 01, 2017 5:34 pm
Forum: Lewis Structures
Topic: Electron Configurations
Replies: 2
Views: 205

### Electron Configurations

Which M3+ ions (where M is a metal) are predicted to have the following ground-state electron configurations:
(a) [Ar]3d6
(b) [Ar]3d5

(a) is Co3+
(b) is Fe3+

I am just very confused as to where these answers came from.
Wed Nov 01, 2017 5:30 pm
Forum: Lewis Structures
Topic: Electron Configurations
Replies: 2
Views: 251

### Electron Configurations

Which M2+ ions (where M is a metal) are predicted to have the following ground-state electrons:
(a) [Ar]3d7
(b) [Ar]3d6

(a) is Co2+
(b) is Fe2+

I am just very confused as to where these answers came from.
Wed Oct 25, 2017 9:05 pm
Forum: Quantum Numbers and The H-Atom
Topic: Subshell Qualities
Replies: 2
Views: 252

### Subshell Qualities

Why is 'The effect nuclear charge Zeff is independent of the number of electrons present in an atom." false?
Wed Oct 25, 2017 9:02 pm
Forum: Quantum Numbers and The H-Atom
Topic: Values of Quantum Numbers
Replies: 3
Views: 754

### Values of Quantum Numbers

(a)How many values of the quantum number l are possible when n=7? (b)How many values of ml are allowed for an electron in a 6d-subshell? (c)How many values of ml are allowed for an electron in a 3p-subshell? (d)How many sub shells are there in the shell with n=4?
Tue Oct 17, 2017 7:51 pm
Forum: DeBroglie Equation
Topic: Wavelike Properties
Replies: 3
Views: 464

### Wavelike Properties

How do you know if a wavelength indicates a particle has wavelike properties or not?
Tue Oct 17, 2017 7:49 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Rydberg Formula
Replies: 2
Views: 219

### Re: Rydberg Formula

I continue to get n=3.2 for this problem.

An excited hydrogen atom emits light with a frequency of 1.14 x 10^14 Hz to reach the energy level n=4. In what principle quantum level did the electron begin?
Wed Oct 11, 2017 5:12 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Replies: 4
Views: 553

What is a good way to remember the categories of electromagnetic radiation?
Wed Oct 11, 2017 5:11 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Energy Level Series
Replies: 2
Views: 207

### Energy Level Series

What do the energy levels conceptually mean or apply to (n=1,n=2,etc) when discussing the H-atom. How do the series names (Lymer, Balmer, etc) relate to anything?
Mon Oct 02, 2017 4:02 pm
Forum: Balancing Chemical Reactions
Topic: Example H.1
Replies: 3
Views: 495

### Re: Example H.1

Allowing for an improper fraction in your balanced equation makes it easier when initially balancing the equation so you don't have to do it in your head. However, a final balanced reaction should contain no fraction stoichiometric coefficients so simply multiply the entire equation by the denominat...
Mon Oct 02, 2017 4:00 pm
Forum: Empirical & Molecular Formulas
Topic: Molarity (Fundamental G, Problem 5b) [ENDORSED]
Replies: 1
Views: 289

### Molarity (Fundamental G, Problem 5b)[ENDORSED]

A student prepared a solution of sodium carbonate by adding 2.111 g of the solid to a 250.0-mL 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 4.98 mmol CO3^2- ion? I used the ...