## Search found 69 matches

Tue Mar 12, 2019 11:28 pm
Forum: First Order Reactions
Topic: using mass or conc in rate laws
Replies: 2
Views: 143

### Re: using mass or conc in rate laws

when working with rate laws, you should be using concentration.
given grams of a substance and volume you can solve for the M which is concentration to plug into rate laws.
Tue Mar 12, 2019 11:24 pm
Forum: First Order Reactions
Topic: Half-Life
Replies: 7
Views: 243

### Re: Half-Life

Half life is used to determine the time it takes for a substance to decompose into half its initial amount.
Tue Mar 12, 2019 11:22 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Negative Order
Replies: 4
Views: 407

### Re: Negative Order

The negative order means that the rate is being decreased instead of the normal increasing rate (positive order).
Tue Mar 12, 2019 11:19 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Rate constant
Replies: 4
Views: 380

### Re: Rate constant

the rate constant, k, will always be positive!
Tue Mar 12, 2019 11:19 pm
Forum: Zero Order Reactions
Topic: Reaction Rate
Replies: 10
Views: 520

### Re: Reaction Rate

It is the same k as long as you use the same products and reactants because the numbers they give are under the same temp.
Fri Mar 01, 2019 12:56 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Reaction Order
Replies: 3
Views: 151

### Re: Cell Reaction Order

anode ll cathode
Fri Mar 01, 2019 12:54 am
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: finding DeltaG
Replies: 6
Views: 218

### Re: finding DeltaG

depending on what is given you will use different equations to solve for deltaG.
Fri Mar 01, 2019 12:53 am
Forum: Van't Hoff Equation
Topic: Van't Hoff use
Replies: 13
Views: 1023

### Re: Van't Hoff use

you use Van't Hoff when you are trying to relate a K value to the increasing temperature T.
Wed Feb 27, 2019 2:50 pm
Forum: Balancing Redox Reactions
Topic: basic/acidic solutions
Replies: 5
Views: 189

### Re: basic/acidic solutions

The problem will specify whether the reaction occurs in basic or acidic solution. Depending on where the reaction takes place you use OH or H20 to balance oxygen and hydrogen.
Wed Feb 27, 2019 2:44 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E^o(cell) vs. Ecell
Replies: 6
Views: 2095

### Re: E^o(cell) vs. Ecell

E^ocell just means the cell potential at standard state. Ecell is the nonstandard state conditions.
Wed Feb 27, 2019 2:42 pm
Forum: Balancing Redox Reactions
Topic: Oxidized vs oxidizing agent
Replies: 6
Views: 164

### Re: Oxidized vs oxidizing agent

Yes, there is a difference. Being oxidized means that molecule is the reducing agent. Being reduced means that the molecule is the oxidizing agent.
Wed Feb 27, 2019 2:38 pm
Forum: Balancing Redox Reactions
Topic: oxidizing agent and reducing agent
Replies: 15
Views: 507

### Re: oxidizing agent and reducing agent

what is being reduced is the oxidizing agent and what is being oxidized is the reducing agent.
Wed Feb 27, 2019 2:37 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: draw galvanic cell
Replies: 3
Views: 172

### Re: draw galvanic cell

we probably don't need to know how to draw a galvanic cell.
Wed Feb 27, 2019 2:34 pm
Forum: Balancing Redox Reactions
Topic: salt bridge vs porous disk
Replies: 4
Views: 436

### Re: salt bridge vs porous disk

the salt bridge and porous disk have the same function which is to balance out both sides of the beaker with salts. salt bridges are represented with two lines and porous only has one.
Tue Feb 19, 2019 12:38 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs free energy
Replies: 7
Views: 229

### Re: Gibbs free energy

Gibbs free energy is the energy that is available to do work, unlike entropy/enthalpy/temperature, it cannot be directly measured.
Tue Feb 19, 2019 12:21 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: System vs Surroundings
Replies: 14
Views: 599

### Re: System vs Surroundings

system is the object, and surrounding is everything around it that can apply heat to it or lose heat.
Tue Feb 19, 2019 12:20 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Test 3
Replies: 10
Views: 358

### Re: Test 3

You mean test 2? test 3 will not include gibbs free energy, but test 2 will.
Mon Feb 04, 2019 4:06 pm
Forum: Phase Changes & Related Calculations
Topic: Heat Curve
Replies: 6
Views: 201

### Re: Heat Curve

It is probably best to understand the heat curve and how to apply it to questions.
Mon Feb 04, 2019 4:05 pm
Forum: Phase Changes & Related Calculations
Topic: Type of systems
Replies: 12
Views: 543

### Re: Type of systems

Closed systems and isolated systems are two different types of systems.
Mon Feb 04, 2019 4:03 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Delta U
Replies: 7
Views: 302

### Re: Delta U

Delta U is the change in internal energy. If it is positive that means the internal energy is increasing while a negative means decreasing.
Mon Feb 04, 2019 4:02 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed and Isolated
Replies: 10
Views: 255

### Re: Closed and Isolated

A closed system is where substance can’t be added or removed, but heat can still be transferred in and out. An isolated system is where heat can not be transferred.
Wed Jan 30, 2019 12:46 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Qsystem+Qsurr=0?
Replies: 6
Views: 438

### Re: Qsystem+Qsurr=0?

The Qsystem and Qsurrounding cancel out for the system to be perfect. Therefore the equation would equal 0.
Wed Jan 30, 2019 12:44 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Heat Capacity
Replies: 8
Views: 245

### Re: Heat Capacity

Heat capacity is an extensive property, while specific heat is an intensive property.
Wed Jan 30, 2019 12:40 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Enthalpy
Replies: 4
Views: 143

### Re: Enthalpy

Delta H is the change in enthalpy.
Wed Jan 30, 2019 12:21 am
Forum: Phase Changes & Related Calculations
Topic: Units: Joules vs kJ
Replies: 5
Views: 234

### Re: Units: Joules vs kJ

As long as you follow the units in the question you should be fine!
Wed Jan 30, 2019 12:11 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Exothermic vs. Endothermic
Replies: 10
Views: 1585

### Re: Exothermic vs. Endothermic

Exothermic reactions release energy, delta H is negative, and heat is a product. Endothermic reactions absorb energy, delta H is positive, and heat is a reactant.
Wed Jan 30, 2019 12:06 am
Forum: Ideal Gases
Topic: Q and K
Replies: 13
Views: 517

### Re: Q and K

K is the constant at equilibrium while Q is approaching the equilibrium. Solving for Q and comparing it to the K constant can get you the direction in which the reaction is favoring.
Wed Jan 23, 2019 12:47 pm
Forum: Ideal Gases
Topic: Concentration or Partial Pressure
Replies: 13
Views: 325

### Re: Concentration or Partial Pressure

the question will tell you when to use Kc or Kp
Wed Jan 23, 2019 12:40 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle on Temperature
Replies: 4
Views: 209

### Re: Le Chatelier's Principle on Temperature

When the reaction is exothermic that means heat is being released as a product. If you are lowering the temperature you are essentially removing heat and that means the reaction will favor the product.
Mon Jan 21, 2019 8:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp vs Kc
Replies: 7
Views: 271

### Re: Kp vs Kc

Kp has to do with the partial pressure while Kc is the concentration.
Mon Jan 21, 2019 8:12 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Water in ICE tables
Replies: 10
Views: 629

### Re: Water in ICE tables

water is omitted because it is a liquid. solids and liquids do not affect the equilibrium.
Mon Jan 14, 2019 12:11 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: equilibrium
Replies: 4
Views: 153

### Re: equilibrium

sits to the left - rxn favors reactants
sits to the right - rxn favors products
Mon Jan 14, 2019 12:10 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Temperature
Replies: 6
Views: 257

### Re: Temperature

The temperature must stay the same in order for the equilibrium constant to stay the same.
Mon Jan 14, 2019 12:08 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: (aq) in calculating K
Replies: 9
Views: 220

### Re: (aq) in calculating K

The aqueous solution is still included in the calculation for K. Only solids and liquids are ignored.
Mon Jan 14, 2019 12:06 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: K vs Q
Replies: 4
Views: 162

### Re: K vs Q

K is the constant at equilibrium, Q is the reaction quotient which means the constant when it is not yet at equilibrium.
However, Q and K can be compared to find which reaction is favored (forward or reverse).
Mon Jan 14, 2019 12:04 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Equilibrium constant
Replies: 6
Views: 225

### Re: Equilibrium constant

Kp and Kc both give the equilibrium constant, but Kp is for partial pressure and Kc is for concentration.
Sun Jan 13, 2019 11:57 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: solids in calculating equilibrium constant? [ENDORSED]
Replies: 8
Views: 345

### Re: solids in calculating equilibrium constant?[ENDORSED]

Solids and liquids are NOT included when calculating the equilibrium constant because a solids concentration would be 100% which is just 1 and doesn't affect the answer.
Only aqueous solutions and gases are included in the calculation of the equilibrium constant.
Sun Jan 13, 2019 11:54 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Tables
Replies: 3
Views: 143

### Re: ICE Tables

ICE tables can be used for concentration or partial pressure!
Tue Dec 04, 2018 4:57 pm
Forum: Sigma & Pi Bonds
Topic: Strength of Sigma and Pi Bonds
Replies: 5
Views: 620

### Re: Strength of Sigma and Pi Bonds

sigma bonds are stronger because the overlap of the sigma bond is smaller than the pi bond so it is harder to break apart.
Tue Dec 04, 2018 4:52 pm
Forum: Electronegativity
Topic: Trend of Electronegativity
Replies: 18
Views: 2964

### Re: Trend of Electronegativity

yes the trends are the same!
Tue Dec 04, 2018 4:52 pm
Forum: Hybridization
Topic: P orbital
Replies: 7
Views: 250

### Re: P orbital

The hybridization depends on the amount of electron densitys. (ex: lone pairs, bonds, etc.)
Tue Dec 04, 2018 4:50 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: polarity
Replies: 11
Views: 295

### Re: polarity

It is better to check the symmetry of the lewis structure.
Thu Nov 29, 2018 6:09 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 3
Views: 83

### Re: Bond Angles

Bond angles are determined by finding out the geometry of the molecule first. (Linear, Tetrahedral, Trigonal Pyramidal etc.) There are helpful charts online!
Thu Nov 29, 2018 6:07 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: VSEPR in equal angles
Replies: 4
Views: 247

### Re: VSEPR in equal angles

yes
Thu Nov 29, 2018 5:58 pm
Forum: Sigma & Pi Bonds
Topic: Sigma vs. Pi
Replies: 11
Views: 770

### Re: Sigma vs. Pi

Single Bond: 1 sigma bond
Double Bond: 1 sigma bond + 1 pi bond
Triple bond: 1 sigma bond + 2 pi bonds
Mon Nov 26, 2018 5:25 pm
Forum: Hybridization
Topic: Hybridization
Replies: 2
Views: 90

### Re: Hybridization

I dont think we are responsible for drawing the hybridization on the test.
Mon Nov 26, 2018 5:22 pm
Forum: Determining Molecular Shape (VSEPR)
Replies: 4
Views: 181

a radical is still treated as a electron density in VSEPR.
Mon Nov 26, 2018 5:19 pm
Forum: Hybridization
Topic: Just Kind of Confused
Replies: 13
Views: 379

### Re: Just Kind of Confused

The order for hybridization does not matter, but it does for electron configuration!
Mon Nov 26, 2018 5:17 pm
Forum: Hybridization
Topic: Lone pair
Replies: 4
Views: 183

### Re: Lone pair

hybridzation depends on the number of regions of electron density. since there is 4 regions (1 lone pair and 3 atoms) the hybridization would be s1p3.
Mon Nov 26, 2018 5:15 pm
Forum: Hybridization
Topic: The Number Before Hybridization
Replies: 3
Views: 146

### Re: The Number Before Hybridization

yes, the number before the hybridzation is the period that the element belongs in.
Mon Nov 26, 2018 5:14 pm
Forum: Sigma & Pi Bonds
Topic: Pi Strength
Replies: 4
Views: 160

### Re: Pi Strength

a sigma bond is stronger than a pi bond, therefore double bonds are stronger than single bonds.
Sun Nov 11, 2018 5:09 pm
Forum: Dipole Moments
Topic: Hydrogen Bonds
Replies: 20
Views: 577

### Re: Hydrogen Bonds

Strongest to weakest
Ionic bond > covalent bond > hydrogen bond > dipole dipole force > London forces
Sun Nov 11, 2018 5:03 pm
Forum: Ionic & Covalent Bonds
Topic: Metallic Bond
Replies: 7
Views: 211

### Re: Metallic Bond

A metallic bond is a bond between two metals ions :)
Sun Nov 11, 2018 4:51 pm
Forum: Lewis Structures
Topic: Formal charges
Replies: 15
Views: 493

### Re: Formal charges

It might be better to calculate the formal charge of each atom so that you can choose the most stable structure.
Sun Nov 11, 2018 4:48 pm
Forum: Lewis Structures
Topic: Expanded Octets
Replies: 9
Views: 428

### Expanded Octets

Which elements can have expanded octets and why?
Sun Nov 11, 2018 4:45 pm
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acid vs base [ENDORSED]
Replies: 15
Views: 557

### Re: Acid vs base[ENDORSED]

Lewis acid accepts electrons while Lewis base donates electrons.
Sun Nov 04, 2018 9:57 pm
Forum: Administrative Questions and Class Announcements
Topic: MIDTERM PRACTICE - Garlic Bread Review Session [ENDORSED]
Replies: 121
Views: 6866

### Re: MIDTERM PRACTICE - Garlic Bread Review Session[ENDORSED]

Thank you for these practice problems!
Sun Oct 28, 2018 9:14 pm
Forum: Photoelectric Effect
Topic: How to calculate the kinetic energy, energy and frequency? [ENDORSED]
Replies: 20
Views: 4285

### Re: How to calculate the kinetic energy, energy and frequency?[ENDORSED]

Thank you for this explanation! This was very helpful.
Sun Oct 28, 2018 9:12 pm
Forum: Ionic & Covalent Bonds
Topic: the Octet rule
Replies: 21
Views: 1064

### Re: the Octet rule

I think that the octet or the half octet is the most stable.
Thu Oct 25, 2018 10:31 pm
Forum: DeBroglie Equation
Topic: Units of De Broglie's Equation
Replies: 4
Views: 775

### Re: Units of De Broglie's Equation

Wavelength can also be converted from meters to nanometers and written in that unit.
Sun Oct 21, 2018 7:56 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: h with a line through it?
Replies: 8
Views: 326

### Re: h with a line through it?

H-bar is equal to h/2pi.
Sun Oct 21, 2018 7:55 pm
Forum: Einstein Equation
Topic: Energy of photon [ENDORSED]
Replies: 12
Views: 927

### Re: Energy of photon[ENDORSED]

When would we use E=ch/wavelength instead of E=hv, vice versa?
Sun Oct 21, 2018 7:47 pm
Forum: Quantum Numbers and The H-Atom
Topic: Electron Shielding
Replies: 2
Views: 141

### Re: Electron Shielding

I remember during lecture he explained electron shielding in a camping scenario. If you are sitting by a fire and someone walks in between you and the fire then you will feel less heat. Same scenario applies to electron shielding in that further electrons feel “less heat” or “less attraction” to the...
Fri Oct 12, 2018 10:33 pm
Forum: DeBroglie Equation
Topic: Equations
Replies: 9
Views: 379

### Re: Equations

Yes, I'm pretty sure we will receive all of the formulas needed to take the test.
Fri Oct 12, 2018 10:23 pm
Forum: SI Units, Unit Conversions
Topic: Should Significant Figures be affected by constants?
Replies: 10
Views: 382

### Re: Should Significant Figures be affected by constants?

Constants do not have an affect on the amount of sig figs to use.
Fri Oct 12, 2018 10:09 pm
Forum: Administrative Questions and Class Announcements
Topic: Advice from a Medical Student [ENDORSED]
Replies: 215
Views: 115140

### Re: Advice from a Medical Student[ENDORSED]

Fri Oct 12, 2018 9:59 pm
Forum: Empirical & Molecular Formulas
Topic: Order of Molecules
Replies: 4
Views: 438

### Re: Order of Molecules

I follow the order that is given in the problem.
Fri Oct 12, 2018 9:55 pm
Forum: Student Social/Study Group
Topic: Post All Chemistry Jokes Here
Replies: 8039
Views: 1409956

### Re: Post All Chemistry Jokes Here

I try to tell chemistry jokes, but there's no reaction.
Fri Oct 12, 2018 9:44 pm
Forum: Administrative Questions and Class Announcements