## Search found 115 matches

Tue Mar 17, 2020 8:43 pm
Forum: General Rate Laws
Topic: Knowing the rate of absorption
Replies: 3
Views: 123

### Re: Knowing the rate of absorption

For the equation aA + bB -> cC + dD, where a,b,c,d are coefficients, the rate of absorption of A and the rate of formation of C are related as such:
(1/a)(d[A]/dt) = (1/c)(d[C]/dt)
Tue Mar 17, 2020 8:42 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Kelvin or Celsius?
Replies: 47
Views: 985

### Re: Kelvin or Celsius?

You use Kelvin, because the unit for R in this equation has K in it.
Tue Mar 17, 2020 8:40 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Concentration Cells
Replies: 8
Views: 148

### Re: Concentration Cells

Concentration cells have two cells where the same half-reactions occur, so when calculating the Ecell, the Ecells of each half-reaction would cancel each other out, since they are for the same reaction (except reversed).
Tue Mar 17, 2020 8:38 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: pH of acids
Replies: 11
Views: 304

### Re: pH of acids

Strong acids disassociate almost completely into hydronium ions, while weak acids only partially disassociate into hydronium ions. If the two acids are at the same concentration, the concentration of hydronium ions will be less for the weak acids. Since pH is the -log of the concentration of hydroni...
Tue Mar 17, 2020 8:37 pm
Forum: Third Law of Thermodynamics (For a Unique Ground State (W=1): S -> 0 as T -> 0) and Calculations Using Boltzmann Equation for Entropy
Topic: Microstates
Replies: 4
Views: 102

### Re: Microstates

Degeneracy is exponentially related to microstates.
Tue Mar 17, 2020 8:35 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Oxidizer vs reducer
Replies: 3
Views: 93

### Re: Oxidizer vs reducer

The oxidizer equation is where the reaction breaks apart electrons from the reactant. The reduction equation adds electrons to the reactant.
Sun Mar 15, 2020 10:49 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: H2O
Replies: 8
Views: 119

### Re: H2O

You don't include any reactant or product in the liquid of solid form when writing out the equation, including H2O.
Sun Mar 15, 2020 10:45 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Electrode Mass
Replies: 10
Views: 162

### Re: Electrode Mass

Because electrode mass is always in excess, changing the mass doesn't do anything to cell potential.
Sun Mar 15, 2020 10:42 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Ea, rate, and temperature
Replies: 4
Views: 62

### Re: Ea, rate, and temperature

As Ea increases, the reaction rate is more strongly dependent on the temperature, so with an increase in temperature, the rate will have a greater change than reactions with a lower Ea.
Sun Mar 15, 2020 10:39 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: isochoric
Replies: 4
Views: 166

### Re: isochoric

Isochoric means constant volume throughout the process, where isometric means the measurements and dimensions stay constant throughout the process.
Sun Mar 15, 2020 10:36 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Galvanic and Voltaic
Replies: 5
Views: 83

### Re: Galvanic and Voltaic

Galvanic and voltaic cells are the same thing; they are spontaneous electrolytic cells.
Sun Mar 15, 2020 10:32 pm
Forum: Zero Order Reactions
Topic: Units
Replies: 9
Views: 122

### Re: Units

For a zero order reaction, the units for k is M/s. The general formula for units of k based on the order, where p is the order of the reaction, is M^(1-P)/s.
Sun Mar 15, 2020 10:29 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Units for reaction rates
Replies: 9
Views: 314

### Re: Units for reaction rates

The general units for k is M^(1-p)/s, where p is the order number. So for 0 order, p=0, M/s. For 1st order, p=1, s^-1. For 2nd order, p=2, M^-1/s.
Mon Mar 09, 2020 12:22 am
Forum: Balancing Redox Reactions
Topic: balancing reactions
Replies: 6
Views: 38

### Re: balancing reactions

So first, you have to figure out which elements are being reduced and oxidized. Then write out the skeletal reactions for the oxidation and the reduction reactions. Then, balance the O's in the reaction by adding H2O. Then balance the H by adding H+ or OH- depending on if it is in acidic or basic so...
Mon Mar 09, 2020 12:18 am
Forum: Administrative Questions and Class Announcements
Replies: 22
Views: 286

We get Test 2 grades back this week in discussion.
Mon Mar 09, 2020 12:18 am
Forum: Balancing Redox Reactions
Topic: oxidation number
Replies: 10
Views: 105

### Re: oxidation number

H is +1, O is -2. The sum of oxidation numbers is equal to the overall charge of the compound, so do some backwards calculations to figure out oxidation numbers of other compounds.
Mon Mar 09, 2020 12:15 am
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Adding Pt(s) to a Cell Diagram
Replies: 14
Views: 146

### Re: Adding Pt(s) to a Cell Diagram

Pt(s) is for when you only have a gaseous substance, or aqueous only.
Mon Mar 09, 2020 12:13 am
Forum: Balancing Redox Reactions
Topic: Determining the oxidizer and reducer
Replies: 10
Views: 96

### Re: Determining the oxidizer and reducer

The oxidizer gains electrons bc they reduce the other agent, and vice versa.
Sun Mar 08, 2020 11:45 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagram
Replies: 7
Views: 84

### Re: Cell diagram

You have to use commas instead of | to separate the two phases.
Sun Mar 01, 2020 10:03 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Writing cell diagrams
Replies: 7
Views: 70

### Re: Writing cell diagrams

Separate species are separated with a comma if they are in the same phase, and | is used for when they are in different phases.
Sun Mar 01, 2020 10:02 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Oxidation Numbers
Replies: 5
Views: 35

### Re: Oxidation Numbers

n in the equation you are referring to is the number of moles of electrons that are transferred. If you balance the half-reactions, the amount of moles of electrons that are lost or gained is n. Some common oxidation rules: H is +1. O is -2. Ions' oxidation numbers are their charges. The sum of oxid...
Sun Mar 01, 2020 9:52 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: identifying cathode/anode
Replies: 4
Views: 94

### Re: identifying cathode/anode

If both species are decreasing in oxidation state then a functioning galvanic cell is not possible.
A cathode is the electrode where electrons are added (reduced).
An anode loses electrons (is oxidized).
Sun Mar 01, 2020 9:46 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: cell potential
Replies: 15
Views: 125

### Re: cell potential

When the cell potential is positive it means the forward reaction will be favored as it is spontaneous. If the cell potential is negative, then the reverse reaction is spontaneous and will be favored.
Sun Mar 01, 2020 9:45 pm
Forum: Balancing Redox Reactions
Topic: Acidic and Basic Reactions
Replies: 9
Views: 85

### Re: Acidic and Basic Reactions

You add H+/OH- ions and H2O to balance out the hydrogens and oxygens in the half reactions. For acidic reactions you add the H+, and for basic reactions you add OH-.
Sun Feb 23, 2020 6:11 pm
Forum: Balancing Redox Reactions
Topic: Flow of electrons
Replies: 11
Views: 91

### Re: Flow of electrons

Electrons only flow from anode(-) to cathode(+), which makes sense since electrons have a negative charge so it will move towards the cathode to try to balance out the charge.
Sun Feb 23, 2020 6:10 pm
Forum: Balancing Redox Reactions
Topic: spontaneous
Replies: 15
Views: 147

### Re: spontaneous

If the standard reduction potential is positive, then the reduction is spontaneous.
Sun Feb 23, 2020 6:08 pm
Forum: Van't Hoff Equation
Topic: Significance of Van't Hoff Equation
Replies: 8
Views: 106

### Re: Significance of Van't Hoff Equation

The equation represents the relationship between the equilibrium constant and the thermodynamic properties enthalpy, temperature, and entropy. This means that we can observe how K changes based on a change in temperature, enthalpy, or entropy.
Sun Feb 23, 2020 6:04 pm
Forum: Balancing Redox Reactions
Topic: Oxidation number of H
Replies: 6
Views: 80

### Re: Oxidation number of H

When hydrogen is in a compound with elements that are less electronegative than it, like a cation or a metal, then its oxidation number will be -1.
Sun Feb 23, 2020 6:01 pm
Forum: Balancing Redox Reactions
Topic: Oxidation States
Replies: 7
Views: 58

### Re: Oxidation States

The oxidation number of Group 1 elements is +1, it is +2 for Group 2 elements, halogens are -1 (in binary compounds). The oxidation number of H is usually +1. Using these facts combined with the rule that the sum of oxidation numbers of ions in a compound has to equal the total charge of that compou...
Sun Feb 23, 2020 5:57 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: chemistry community posts
Replies: 12
Views: 81

### Re: chemistry community posts

The posts are checked after midnight every Sunday; so you have to submit 5 posts between Monday to the end of Sunday.
Mon Feb 17, 2020 12:31 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Ph
Replies: 8
Views: 92

### Re: Ph

The pH is always calculated when the solution is at equilibrium, unless specifically said otherwise (but this doesn't happen). So yes, you can always calculate the H+ concentration from the given pH, but it will be the H+ concentration at equilibrium.
Mon Feb 17, 2020 12:30 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Signs for Gibbs Free Energy
Replies: 11
Views: 142

### Re: Signs for Gibbs Free Energy

When G is negative, the reaction is spontaneous and thermodynamically stable, and if G is positive the reaction is non-spontaneous and thermodynamically unstable. You can calculate this using the equation G = H - TS.
Mon Feb 17, 2020 12:28 am
Forum: Gibbs Free Energy Concepts and Calculations
Topic: thermodynamically stable
Replies: 6
Views: 105

### Re: thermodynamically stable

A reaction is thermodynamically stable when delta G (change in Gibbs free energy is less than 0). This usually means that delta H is negative and delta S is positive, but depending on the temperature of the reaction, it can be thermodynamically unstable or stable.
Mon Feb 17, 2020 12:27 am
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Second law of thermodynamics
Replies: 6
Views: 136

### Re: Second law of thermodynamics

The second law of thermodynamics is that the entropy (chaos) of the universe is always increasing.
Mon Feb 17, 2020 12:26 am
Forum: Balancing Redox Reactions
Topic: oxidation number
Replies: 10
Views: 105

### Re: oxidation number

You can just memorize the charge for the basic elements like oxygen, nitrogen, carbon, hydrogen, etc. And the others are pretty similar to their ion charge, so just know that.
Sun Feb 09, 2020 11:49 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Intensive
Replies: 8
Views: 114

### Re: Intensive

Entropy is not an intensive property; it is an extensive property and state function that depends on the mass and the current state of the substance.
Sun Feb 09, 2020 11:47 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm
Replies: 12
Views: 153

### Re: Midterm

The midterm will be 6-8 PM, the locations are on the Chem 14B page.
Sun Feb 09, 2020 11:46 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: State Functions
Replies: 5
Views: 63

### Re: State Functions

State functions are Enthalpy, Pressure, Volume, Temperature, density, and heat capacity, internal energy, Gibbs free energy, and entropy.
Sun Feb 09, 2020 11:43 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: extensive vs intensive
Replies: 4
Views: 66

### Re: extensive vs intensive

An extensive property is a property that changes depending on the mass of the substance involved, such as heat capacity. An intensive property is one that stays constant no matter the amount of substance, such as density or specific heat capacity.
Sun Feb 09, 2020 11:42 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Cv vs. Cp
Replies: 5
Views: 52

### Re: Cv vs. Cp

Cv refers to the molar heat capacity of a gas at constant volume. Cp refers to the molar heat capacity of a gas at constant pressure. The two are different because in order to maintain the same pressure throughout a reaction the volume would have to be changing, and maintaining volume would require ...
Mon Feb 03, 2020 12:03 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Universe Closed System
Replies: 3
Views: 45

### Re: Universe Closed System

The universe does not exchange matter or energy with anything surrounding it (as far as I know), which is why it fits the definition of an isolated system. I don't think it is a closed system because there isn't any surrounding to exchange energy with.
Mon Feb 03, 2020 12:00 am
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: work and volume
Replies: 4
Views: 58

### Re: work and volume

Work is equal to the pressure times the volume.
Sun Feb 02, 2020 11:55 pm
Forum: Phase Changes & Related Calculations
Topic: Calorimeters
Replies: 8
Views: 57

### Re: Calorimeters

Yes, it does matter if its a bomb calorimeter versus a regular calorimeter. A bomb calorimeter is an isolated system so you would have to solve accordingly. All other calorimeters are regular, and it doesn't matter otherwise.
Sun Feb 02, 2020 11:50 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Specific heat capacity
Replies: 7
Views: 75

### Re: Specific heat capacity

Both are forms of heat capacity. Specific heat capacity is the amount of heat required to raise one gram of the substance by one degree Celsius/Kelvin. Molar heat capacity is the amount of heat required to raise one mole of substance by one degree Celsius/Kelvin. Both are intensive properties.
Sun Feb 02, 2020 11:49 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Closed System
Replies: 7
Views: 98

### Re: Closed System

A closed system by definition goes cannot exchange matter with its surroundings. If the car is the system and the environment is the surrounding, then a car cannot be a closed system because it released exhaust (which is matter) into the environment.
Sun Feb 02, 2020 11:46 pm
Forum: Ideal Gases
Topic: Ideal gas constant
Replies: 4
Views: 65

### Re: Ideal gas constant

The different gas constants account for the different unit forms of pressure, volume, and temperature. Basically, you have to choose the R value that matches the units provided to you in the problem. Or you can just figure out which R, when used in calculations, will cause all the units to cancel out.
Sun Feb 02, 2020 11:42 pm
Forum: Phase Changes & Related Calculations
Topic: intensive/extensive
Replies: 4
Views: 43

### Re: intensive/extensive

An intensive property is a characteristic of a substance that does not change no matter the amount or quantity of the substance. An example would be density or specific heat capacity. An extensive property is a characteristic of a substance that does change based on the amount or mass of the substan...
Sun Feb 02, 2020 11:39 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: closed vs isolated?
Replies: 7
Views: 87

### Re: closed vs isolated?

An isolated system doesn't exchange mass or energy/heat with the surroundings, like an insulated thermos with the lid screwed on. A closed system doesn't exchange matter with the surroundings; but it can exchange energy. So for example heating liquids in a pot with the lid closed is a closed system ...
Sun Feb 02, 2020 11:38 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Forming bonds
Replies: 8
Views: 63

### Re: Forming bonds

Forming bonds is usually is the most stable form of the molecules; which is why energy is released when the bonds form. However I'm pretty sure there are a few very rare cases when bond formation is more unstable, in which case it would be endothermic.
Sun Feb 02, 2020 11:23 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Heat capacity vs. specific heat capacity
Replies: 3
Views: 49

### Re: Heat capacity vs. specific heat capacity

Heat capacity is the amount of heat needed to raise a mass of a substance by one degree Celsius/Kelvin. Specific heat is a variation of heat capacity in that specific heat is the amount of heat needed to raise one unit of mass of a substance by one degree Celsius/Kelvin. Specific heat remains the sa...
Sun Feb 02, 2020 11:09 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Isolated system
Replies: 10
Views: 156

### Re: Isolated system

By definition an isolated system does not exchange matter or energy/heat with its surroundings. Most systems cannot be perfectly isolated, but can come very close. An insulated thermos with the lid screwed on tightly is an example of an isolated system, because the insulated prevents almost no heat ...
Mon Jan 20, 2020 2:16 am
Forum: Ideal Gases
Topic: PV=nRT
Replies: 13
Views: 141

### Re: PV=nRT

You can use this equation to find partial pressures of the components of the reaction (P) if you know the volume, temperature and molar concentration. Then you could find the equilibrium constant Kp by plugging in the partial pressures into the formula for Kp.
Mon Jan 20, 2020 2:12 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Q
Replies: 6
Views: 119

### Re: Q

Q and K are solved in the same way, however, K is the equilibrium constant by definition, while Q is the reaction quotient which can be found at any point in the reaction timeline, and based on whether Q is less than, greater than, or equal to K predictions about the reactions future can be made.
Mon Jan 20, 2020 2:11 am
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: pH for weak acids
Replies: 5
Views: 235

### Re: pH for weak acids

Weak acids disassociate into a less concentrated solution of hydronium ions in comparison to strong acids. Since pH is the negative log of hydronium ion concentration; weak acids would have higher pH values (negative log is basically the logarithm of 1/[hydronium ion])
Mon Jan 20, 2020 2:08 am
Forum: Administrative Questions and Class Announcements
Topic: TeST 1
Replies: 5
Views: 62

### Re: TeST 1

Test 1 will be on chemical equilibrium and acids and bases. Everything on outlines 1 and 2 will be covered.
Mon Jan 20, 2020 2:07 am
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Combining Reactions
Replies: 3
Views: 32

### Re: Combining Reactions

You simply need to multiple the K values for the two equations; if by chance one of the equations has to by multiples by a factor, take K to the power of that factor and continue normally.
Sun Jan 12, 2020 11:00 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: Calculating Q
Replies: 16
Views: 182

### Re: Calculating Q

The rule is to include all aqueous solutions and gases, just like you would to calculate K.
Sun Jan 12, 2020 10:41 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units for K
Replies: 21
Views: 217

### Re: Units for K

There is no unit for K, it is a constant for equilibrium. You can prove this because when you solve for K, all the units cancel out.
Sun Jan 12, 2020 10:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Concentration
Replies: 6
Views: 77

### Re: Concentration

Concentration does have a unit (moles/liter). But, equilibrium constants do not have units.
Sun Jan 12, 2020 10:31 pm
Forum: Ideal Gases
Topic: Kc and Kp
Replies: 8
Views: 65

### Re: Kc and Kp

Both are equilibrium ocnstants, but Kc is calculated from concentrations, and Kp is calculated from partial pressures.
Sun Jan 12, 2020 8:37 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Units for K
Replies: 21
Views: 217

### Re: Units for K

K is a constant because when calculating it all the units cancel out, so there is no unit for it.
Sun Jan 12, 2020 8:32 pm
Forum: Ideal Gases
Topic: PV=nRT
Replies: 3
Views: 18

### Re: PV=nRT

R is the ideal gas constant, 8.3145 J*mol^-1*K^-1
Sun Dec 08, 2019 11:42 pm
Forum: Naming
Topic: "Ferrate"
Replies: 14
Views: 790

### Re: "Ferrate"

When the complex is an anion, you use the latin prefix (only if there is one) for the metal, and end it in -ate.
Sun Dec 08, 2019 11:42 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty
Replies: 7
Views: 413

### Re: Uncertainty

Yes the two terms are used interchangeably.
Sun Dec 08, 2019 11:38 pm
Forum: Student Social/Study Group
Topic: amphoteric vs. amphiprotic
Replies: 4
Views: 153

### Re: amphoteric vs. amphiprotic

Amphiprotic means that the molecule can either accept or donate a proton in a reaction.
Amphoteric means that the molecule can react as either an acid or base in a reaction.
Normally, there is overlap.
Sun Dec 08, 2019 11:32 pm
Forum: Bronsted Acids & Bases
Topic: amphoteric
Replies: 7
Views: 224

### Re: amphoteric

A molecule is amphoteric if it can react as an acid or a base in an acid-base reaction.
Sun Dec 08, 2019 11:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: H3O+
Replies: 11
Views: 6752

### Re: H3O+

The Lewis structure has 8 electrons, and when drawing the Lewis structure there are three bonds to the oxygen, with one lone pair. So there are 4 electron domains, so the molecular geometry is tetrahedral. But one electron domain is a lone pair, so the actual shape is trigonal pyramidal.
Sun Dec 08, 2019 10:38 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Uncertainty
Replies: 5
Views: 158

### Re: Uncertainty

Delta x signifies the change in position of the electron.
Sun Dec 08, 2019 10:33 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH
Replies: 6
Views: 153

### Re: pH

By definition the pH is the -log of the concentration of hydronium atoms. It is simply a mathematical representation of the hydronium ion concentration.
The pOH is the -log of the concentration of hydroxide ions.
Sun Dec 08, 2019 10:32 pm
Forum: Naming
Topic: NH4[PtCl3(NH3)]
Replies: 5
Views: 140

### Re: NH4[PtCl3(NH3)]

You use platinate instead of platinum because the charge of the overall complex is negative, so its an anion. The rule is that when the charge of the complex is an ion, you end the metal with -ate.
Mon Dec 02, 2019 11:20 am
Forum: Sigma & Pi Bonds
Topic: Sigma vs. Pi
Replies: 15
Views: 389

### Re: Sigma vs. Pi

Sigma bonds are stronger than pi bonds because if you look at the 3D diagram of the orbitals, the heads of the two p orbitals in a sigma bond overlap, where as a pi bond is simply the attraction of two parallel p orbitals. This overlap is why sigma bonds are stronger.
Mon Dec 02, 2019 11:13 am
Forum: Conjugate Acids & Bases
Topic: Conjugate Acids and Bases
Replies: 4
Views: 66

### Re: Conjugate Acids and Bases

A conjugate acid of a base is basically the base attached to a proton (hydrogen ion). Likewise, the conjugate base of an acid is the acid without a proton (hydrogen ion). It is basically a reaction of the addition/removal of a hydrogen ion, and the reactant and product are conjugates of each other.
Mon Dec 02, 2019 11:10 am
Forum: Calculating the pH of Salt Solutions
Topic: pH of acids
Replies: 13
Views: 634

### Re: pH of acids

Strong acids dissociate far more than weak acids do, which means that they release more hydrogen ions into the solution; this makes the solution more pH, since pH by definition is related to the inverse of the measure of hydrogen ions (the more hydrogen ions there are, the lower the pH is).
Mon Dec 02, 2019 11:07 am
Forum: Naming
Topic: Coordination Compound: Cation or Anion
Replies: 3
Views: 45

### Re: Coordination Compound: Cation or Anion

When writing the formulas for coordination compounds, you should start with the complex cation and put that in brackets, then follow it with the anion. Putting it the other way, while it may not be wrong, is abnormal so you should just avoid writing the formula that way.
Mon Dec 02, 2019 11:05 am
Forum: Properties & Structures of Inorganic & Organic Acids
Topic: Acids Vs. Bases
Replies: 11
Views: 170

### Re: Acids Vs. Bases

The most general difference is that an acid gives off hydrogen ions in water, whereas bases give of hydroxide ions in water. If you are talking about Lewis acids and bases, however, then the difference is that Lewis acids accept electrons from other molecules, while Lewis bases donate electrons to o...
Sun Nov 24, 2019 9:39 pm
Forum: Sigma & Pi Bonds
Topic: Molecular Shape
Replies: 11
Views: 127

### Re: Molecular Shape

No, sigma and pi bonds do not influence a molecule's shape (in other words, the type of bond doesn't affect the shape).
Sun Nov 24, 2019 9:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polarity
Replies: 3
Views: 58

### Re: Polarity

Yes we will need to know how to determine polarity of all kinds of molecules, including the example you gave. That would be polar because of the presence of oxygen bonds and a non-symmetrical arrangement.
Sun Nov 24, 2019 9:30 pm
Forum: Hybridization
Topic: sigma or pi?
Replies: 20
Views: 281

### Re: sigma or pi?

When you draw the Lewis structure, a signle bond has one sigma bond, a double bond has one sigma and one pi bond, and a triple bond has one sigma and two pi bonds.
Sun Nov 24, 2019 9:29 pm
Forum: Administrative Questions and Class Announcements
Replies: 10
Views: 168

We will get them in discussion next week most likely.
Sun Nov 24, 2019 9:28 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: H3O+
Replies: 11
Views: 6752

### Re: H3O+

H3O+ is tetrahedral because when drawing the lewis structure, there are a total of 8 electrons, and so oxygen should have 3 bonds (to hydrogens) and then one lone pair, which means there are four regions of electron density about the central atom, which means the molecular geometry is tetrahedral, b...
Sun Nov 17, 2019 9:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lewis Structures
Replies: 6
Views: 68

### Re: Lewis Structures

To determine shape all you need to know is the number of lone pairs and the number of bonds about the central atom, so if you draw the Lewis structure right then that's all you need to know.
Sun Nov 17, 2019 9:28 pm
Forum: Lewis Structures
Topic: Why can Xenon break the octet rule?
Replies: 8
Views: 441

### Re: Why can Xenon break the octet rule?

Like other elements with n=3 or higher, xenon has an empty d-orbital, specifically the 5d orbital, which can fill up with the extra electrons.
Sun Nov 17, 2019 9:25 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 18
Views: 394

### Re: Resonance Structures

Resonance structures are the multiple Lewis structures a single molecule can have.
Sun Nov 17, 2019 9:23 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar vs. Nonpolar
Replies: 8
Views: 92

### Re: Polar vs. Nonpolar

For example, in the molecule CO2, the bond C-O itself is polar, but since the molecule CO2 is linear (O-C-O), the polarity of each bond cancels each other out due to the symmetric shape of the molecule. This concepts applies to most types of molecules.
Sun Nov 17, 2019 9:21 pm
Forum: Student Social/Study Group
Topic: Final Exam
Replies: 10
Views: 181

### Re: Final Exam

Yes, the final exam includes everything we've learned this quarter.
Sun Nov 17, 2019 9:11 pm
Forum: Student Social/Study Group
Topic: Test 2
Replies: 11
Views: 147

### Re: Test 2

The first part of Monday's lecture will be the newest information on the test. Other than that its everything since the midterm.
Sun Nov 17, 2019 8:33 pm
Forum: Determining Molecular Shape (VSEPR)
Replies: 5
Views: 63

A radical is considered a region of electron density and affects bond length as other lone electron pairs do.
Tue Nov 12, 2019 9:22 pm
Forum: Resonance Structures
Topic: Formal Charge Question
Replies: 15
Views: 346

### Re: Formal Charge Question

The only requirement is for the sum of the formal charges to add up to the overall charge.
Tue Nov 12, 2019 9:17 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 9
Views: 265

### Re: Formal Charge

You can underline the formal charges or something to distinguish them from the atom and the electron dots.
Mon Nov 11, 2019 1:42 pm
Forum: Octet Exceptions
Topic: More then 8 electrons
Replies: 5
Views: 167

### Re: More then 8 electrons

It is only allowed when the the central atom with the expanded octet is in the 3rd row of the periodic table or below, because only these elements have a d-orbital.
Mon Nov 11, 2019 1:40 pm
Forum: Electronegativity
Topic: Noble Gases
Replies: 23
Views: 1129

### Re: Noble Gases

No, fluorine has the highest electronegativity in all the periodic table; the noble gases have a complete octet so they would not want another electron.
Mon Nov 11, 2019 1:38 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: Test 2
Replies: 6
Views: 71

### Re: Test 2

I don't think it will be pushed back.
Mon Nov 11, 2019 1:38 pm
Forum: Bond Lengths & Energies
Topic: Shorter bond lengths
Replies: 12
Views: 118

### Re: Shorter bond lengths

It's because more electrons are involved in the bond so the pull is stronger bringing in the atoms closer together.
Mon Nov 11, 2019 1:38 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole moment
Replies: 4
Views: 54

### Re: Dipole moment

A dipole moment is the measure of polar covalence of a bond in molecule.
Sun Nov 03, 2019 11:46 pm
Forum: Lewis Structures
Topic: formal charge
Replies: 6
Views: 45

### Re: formal charge

You only have to check the formal charge if they ask you to, other than that you do it just to verify your answer.
Sun Nov 03, 2019 11:45 pm
Forum: Quantum Numbers and The H-Atom
Topic: Magnetic Quantum Number
Replies: 3
Views: 40

### Re: Magnetic Quantum Number

It will always be plus or minus 1/2, and there's no specific way to find out the answer, they normally dont ask you to determine it.
Sun Nov 03, 2019 11:43 pm
Forum: Electronegativity
Topic: Ionic or covalent?
Replies: 17
Views: 215

### Re: Ionic or covalent?

Normally ionic bonds happen between elements far from each other on the periodic table, with a metal and nonmetal. Covalent bonds are everything else
Sun Nov 03, 2019 11:43 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal charge
Replies: 16
Views: 225

### Re: Formal charge

Just make sure the formal charges are as close to 0 as possible.
Sun Nov 03, 2019 11:42 pm
Forum: Photoelectric Effect
Topic: Best way to study for this topic?
Replies: 8
Views: 268

### Re: Best way to study for this topic?

If its a little hard to find practice problems, I would replace numbers of the problems and redo the problem, and just like alter the data a little bit.
Sun Oct 20, 2019 5:13 pm
Forum: DeBroglie Equation
Topic: 1B.21
Replies: 3
Views: 92

### Re: 1B.21

First convert the 5.15 ounces to grams using the conversion factor that is provided. Then you have to convert the 92 mph to meters per second by using the miles to meters conversion factor and the hours to minutes to seconds conversion factors (you might have to look this up online). Then plug the d...