Search found 45 matches

by Ashley Alvarado 2C
Sat Mar 14, 2020 8:45 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation
Replies: 6
Views: 104

Re: Nernst Equation

That conversion is useful when the system is at room temperature.
by Ashley Alvarado 2C
Sat Mar 14, 2020 8:41 pm
Forum: Van't Hoff Equation
Topic: ln
Replies: 9
Views: 131

Re: ln

Both sides should be raised to the power of e to get rid of ln and to get the answer.
by Ashley Alvarado 2C
Sat Mar 14, 2020 8:36 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: negative sign
Replies: 6
Views: 113

Re: negative sign

delta G*= -nFE
w(max)=-nFE
The system is doing work, so energy leaves the system resulting in -w.
by Ashley Alvarado 2C
Sat Mar 14, 2020 8:30 pm
Forum: Balancing Redox Reactions
Topic: oh
Replies: 11
Views: 199

Re: oh

OH- can be added to balance oxygen only if it is a basic solution.
by Ashley Alvarado 2C
Sat Mar 14, 2020 8:28 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Delta S
Replies: 8
Views: 119

Re: Delta S

delta S(univ)= delta S(sys) + delta S(surr)
by Ashley Alvarado 2C
Sat Mar 14, 2020 8:21 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: intensive vs extensive
Replies: 7
Views: 141

Re: intensive vs extensive

Extensive properties depend on the amount of substance, while intensive properties do not depend on the amount.
by Ashley Alvarado 2C
Sat Mar 14, 2020 8:17 pm
Forum: General Rate Laws
Topic: integrals and derivatives
Replies: 7
Views: 110

Re: integrals and derivatives

I think the derivatives and integrals were to show how equations are derived.
by Ashley Alvarado 2C
Sat Mar 14, 2020 8:14 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Gibbs free energy
Replies: 9
Views: 143

Re: Gibbs free energy

Delta G* is the Gibbs free energy at standard conditions which are 1M, 25 degrees C, and 1 atm.
by Ashley Alvarado 2C
Sat Mar 14, 2020 8:10 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kw and other constants
Replies: 9
Views: 120

Re: Kw and other constants

The w in Kw represents the equilibrium constant for water. KA x KB= Kw which is equal to [H30+][OH-].
by Ashley Alvarado 2C
Sat Mar 14, 2020 8:05 pm
Forum: Ideal Gases
Topic: Partial Pressure
Replies: 13
Views: 141

Re: Partial Pressure

According to Le Chatelier's principle if there are more moles on the right side then the reaction shifts right creating more products.
by Ashley Alvarado 2C
Sun Mar 08, 2020 9:47 pm
Forum: First Order Reactions
Topic: Graphing 1st order reaction rates
Replies: 6
Views: 45

Re: Graphing 1st order reaction rates

For first order reactions, ln[A] is graphed against time for a linear graph which gives the slope. If just [A] were graphed against time, then the graph would be exponential.
by Ashley Alvarado 2C
Sun Mar 08, 2020 9:40 pm
Forum: Second Order Reactions
Topic: Termolecular
Replies: 15
Views: 427

Re: Termolecular

Termolecular refers to the simultaneous collision of three species.
by Ashley Alvarado 2C
Sun Mar 08, 2020 9:37 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: A
Replies: 8
Views: 53

Re: A

[A] is the concentration of the reactants and [A]0 is the initial concentration.
by Ashley Alvarado 2C
Sun Mar 08, 2020 9:30 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: K
Replies: 11
Views: 69

Re: K

The rate constant (k) depends on temperature and activation energy.
by Ashley Alvarado 2C
Sun Mar 08, 2020 9:26 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Molecularity
Replies: 12
Views: 116

Re: Molecularity

Molecularity is the number of species in an elementary step meaning the number of molecules in a reaction that act as reactants.
by Ashley Alvarado 2C
Sun Mar 08, 2020 9:22 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Cell Diagram
Replies: 16
Views: 201

Re: Cell Diagram

I think it is safe to assume that the anode will be on the left while the cathode will be on the right.
by Ashley Alvarado 2C
Sun Mar 08, 2020 9:19 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: K < >
Replies: 8
Views: 84

Re: K < >

To determine if K is < or > 1 look at the ratio of the concentration of products over reactants. If there are more products than reactants, K>1. If there are more reactants than products, K<1. When K>1 (more products), the E of the cell will be positive.
by Ashley Alvarado 2C
Sun Mar 01, 2020 10:03 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: when to use K or Q
Replies: 18
Views: 233

Re: when to use K or Q

If the reaction is at equilibrium, then K is used, but if the reaction is not at equilibrium then Q is used.
by Ashley Alvarado 2C
Sun Mar 01, 2020 10:01 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cell potential
Replies: 15
Views: 119

Re: cell potential

If the E value is positive, this means that the deltaG value is negative, so the process is spontaneous.
by Ashley Alvarado 2C
Sun Mar 01, 2020 9:57 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Salt Bridge
Replies: 12
Views: 107

Re: Salt Bridge

A salt bridge allows ion transfer so the two solutions stay neutral. Without the salt bridge, e- transfer would stop due to charge buildup.
by Ashley Alvarado 2C
Sun Mar 01, 2020 9:42 pm
Forum: Balancing Redox Reactions
Topic: Acidic and Basic Reactions
Replies: 9
Views: 85

Re: Acidic and Basic Reactions

When balancing half reactions, H+ is added to balance H and OH- is added to balance O.
by Ashley Alvarado 2C
Sun Mar 01, 2020 9:35 pm
Forum: Balancing Redox Reactions
Topic: oxidizing agents
Replies: 11
Views: 115

Re: oxidizing agents

The oxidizing agent has the ability to oxidize and is itself reduced. The reducing agent reduces and is itself oxidized.
by Ashley Alvarado 2C
Sun Feb 23, 2020 6:39 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: standard conditions
Replies: 8
Views: 69

Re: standard conditions

Solutes with a concentration of 1M and gases of 1 atm at 273.15K are in standard condition.
by Ashley Alvarado 2C
Sun Feb 23, 2020 6:31 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: work
Replies: 8
Views: 79

Re: work

If a system is doing work on its surroundings, then work is being lost and work is negative. If the surroundings are doing work on the system, then work is being gained and work is positive. In the case of a battery, the system is doing work so the amount of energy that leaves the system is negative.
by Ashley Alvarado 2C
Sun Feb 23, 2020 6:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Platinum
Replies: 4
Views: 38

Re: Platinum

The left side of the cell diagram has a solid (copper), while the right side only has iron in aqueous states, so because of this a solid such as platinum is added to the right. The platinum is an inert conductor which acts as an electrode to transfer electrons.
by Ashley Alvarado 2C
Thu Feb 20, 2020 5:33 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Adiabatic systems
Replies: 11
Views: 185

Re: Adiabatic systems

q will always equal 0 in adiabatic systems because there is no heat flow.
by Ashley Alvarado 2C
Thu Feb 20, 2020 5:29 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Adding Inert Gas
Replies: 20
Views: 290

Re: Adding Inert Gas

When an inert gas is added, the pressure does increase, but there is no change in the concentrations of the products and the reactants. Because of this there is no effect on the reaction.
by Ashley Alvarado 2C
Mon Feb 10, 2020 10:44 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Intensive vs. extensive, state vs. non state
Replies: 6
Views: 71

Re: Intensive vs. extensive, state vs. non state

Heat capacity is an extensive property that depends on the amount of a substance, if the heat capacity is divided by the amount of substance then you have an intensive property known as specific heat capacities.
by Ashley Alvarado 2C
Mon Feb 10, 2020 10:36 pm
Forum: Calculating Work of Expansion
Topic: calculating work of a reversible reaction
Replies: 5
Views: 67

Re: calculating work of a reversible reaction

If a system is doing work on the surroundings in the instance of expansion, then work is being lost so work will be negative.
by Ashley Alvarado 2C
Mon Feb 10, 2020 10:27 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy Change due to Changes in Temperature
Replies: 2
Views: 30

Re: Entropy Change due to Changes in Temperature

I think that temperature would have to be in Kelvin. In this class, whenever temperature is brought up it is almost always converted to kelvin.
by Ashley Alvarado 2C
Mon Feb 10, 2020 10:06 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Molar Concentration Direction.
Replies: 2
Views: 33

Re: Molar Concentration Direction.

It is always assumed that the concentration of the reactants decreases by x, so in this example the reactants N2 changes by -2x (because of the coefficient when you balance the chemical equation) and O2 changes by -x.
by Ashley Alvarado 2C
Mon Feb 10, 2020 9:56 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ICE BOX
Replies: 27
Views: 244

Re: ICE BOX

X will be too small if it is less than 5% of the initial and if K<10^-3.
by Ashley Alvarado 2C
Mon Feb 10, 2020 9:53 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: X is to small
Replies: 8
Views: 144

Re: X is to small

When Kc< 10^-3 and x is less than 5% of the initial concentration then it is okay to approximate.
by Ashley Alvarado 2C
Fri Jan 31, 2020 4:32 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Volume and Pressure
Replies: 8
Views: 101

Re: Volume and Pressure

They are inversely related, meaning if the pressure increases then volume will decrease and vice versa.
by Ashley Alvarado 2C
Fri Jan 31, 2020 4:26 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Hess' Law
Replies: 7
Views: 55

Re: Hess' Law

Enthalpy changes can be added and subtracted because enthalpy is a state property.
by Ashley Alvarado 2C
Thu Jan 30, 2020 5:27 pm
Forum: Calculating Work of Expansion
Topic: Application
Replies: 1
Views: 29

Re: Application

I don't think we will be asked to show how the equation for work: w=-P(deltaV) is derived.
by Ashley Alvarado 2C
Thu Jan 30, 2020 5:15 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Constant Pressure
Replies: 7
Views: 70

Re: Constant Pressure

If pressure or volume are constant, there is no change between the final and initial values.
by Ashley Alvarado 2C
Thu Jan 30, 2020 5:12 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Units for work
Replies: 3
Views: 30

Re: Units for work

The textbook converts L x atm to J or kJ.
by Ashley Alvarado 2C
Thu Jan 30, 2020 4:48 pm
Forum: Phase Changes & Related Calculations
Topic: State Functions
Replies: 9
Views: 84

Re: State Functions

Enthalpy would be considered a state function, meaning it must be able to be added. Change in enthalpy can be added to give the total enthalpy change.
by Ashley Alvarado 2C
Mon Jan 20, 2020 10:39 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: pKa and pKb
Replies: 17
Views: 201

Re: pKa and pKb

pKa and pKb are acidity and basicity constants which are given as their negative log:
pKa=-log(ka)
pKb=-log(kb)
by Ashley Alvarado 2C
Mon Jan 20, 2020 10:33 pm
Forum: Ideal Gases
Topic: Acid and Bases
Replies: 16
Views: 139

Re: Acid and Bases

So if a reaction produces more H30+ ions it is more acidic, does this means that the more OH- ions a reaction produces the more basic it is?
by Ashley Alvarado 2C
Mon Jan 20, 2020 10:29 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: 5% Rule
Replies: 6
Views: 86

Re: 5% Rule

Yes, the 5% rule is used to get a valid approximation without having to use the quadratic formula when calculating for both acid base and chemical equilibria.
by Ashley Alvarado 2C
Mon Jan 20, 2020 10:25 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Pressure changes
Replies: 7
Views: 49

Re: Pressure changes

If the partial pressure of a reactant was increased, the volume will decrease and there will be more moles of gas on the right, so the reaction shifts left.
by Ashley Alvarado 2C
Mon Jan 20, 2020 10:19 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: X was ignored
Replies: 27
Views: 204

Re: X was ignored

The -x can be ignored because it was small relative to the initial concentration.

Go to advanced search