## Search found 63 matches

Mon Mar 18, 2019 10:35 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Enzyme
Replies: 3
Views: 696

### Re: Enzyme

catalysts lower the activation energy of reactions and speed them up. and an enzyme is an example of one of them
Mon Mar 18, 2019 10:34 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Enzyme
Replies: 3
Views: 696

### Re: Enzyme

an enzyme acts as a catalyst in reactions.
Mon Mar 18, 2019 10:32 pm
Forum: Calculating Work of Expansion
Topic: Work
Replies: 3
Views: 738

### Re: Work

if there is no change in volume, no work is done. If there is no change in pressure, you would use one of the given formulas
Mon Mar 18, 2019 10:32 pm
Forum: Calculating Work of Expansion
Topic: Work
Replies: 3
Views: 738

### Re: Work

then there is no work if there is no change in volume
Sun Mar 10, 2019 11:08 pm
Forum: First Order Reactions
Topic: Half-Life
Replies: 7
Views: 125

### Re: Half-Life

half life refers to the time it takes for a substance to decay by one-half of its initial amount. Half life and its equation are used to determine how old a substance is, the initial amount of a substance, or the final amount of a substance after a period of time
Sun Mar 10, 2019 11:04 pm
Forum: Second Order Reactions
Topic: Final
Replies: 30
Views: 559

### Re: Final

The final definitely will be cumulative. The format will most likely be that there is a question with many parts for each topic we discussed, ex a question on kinetics, a question on electrochem, a question on thermodynamics
Sun Mar 10, 2019 10:46 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: rate determining
Replies: 3
Views: 71

### Re: rate determining

The rate determining step will be the slowest step in the reaction, and that determines the rate law of the overall reaction
Sun Mar 10, 2019 10:44 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: molecularity
Replies: 8
Views: 148

### Re: molecularity

unimolecular refers to one species, bimolecular refers to two species, and termolecular refers to three species
Sun Mar 10, 2019 10:41 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: molecularity
Replies: 8
Views: 148

### Re: molecularity

The molecularity refers to the number of species in an elementary step, you can think of it as having to do with the number of reactants in the reaction
Sun Feb 24, 2019 11:54 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: n in -nFE
Replies: 6
Views: 95

### Re: n in -nFE

n represents the number of electrons transferred in the process
Sun Feb 24, 2019 11:51 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy Units
Replies: 5
Views: 115

### Re: Gibbs Free Energy Units

If a certain reaction is involved, the answer should be in units of kJ/mol
Sun Feb 24, 2019 11:48 pm
Forum: Balancing Redox Reactions
Topic: Redox Rxns in Acidic and Basic Solutions
Replies: 6
Views: 116

### Re: Redox Rxns in Acidic and Basic Solutions

The problem would specify if the reaction was happening in an acidic or basic environment
Sun Feb 24, 2019 11:48 pm
Forum: Balancing Redox Reactions
Topic: Redox Rxns in Acidic and Basic Solutions
Replies: 6
Views: 116

### Re: Redox Rxns in Acidic and Basic Solutions

The problem would specify if the reaction was happening in an acidic or basic environment
Sun Feb 24, 2019 11:46 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: determining n
Replies: 4
Views: 87

### Re: determining n

It most likely has to do with the coefficient in front of the substance used in the equation
Sun Feb 24, 2019 11:43 pm
Forum: Student Social/Study Group
Topic: Test 2
Replies: 3
Views: 85

### Re: Test 2

This is what he said on his website: "Test 2 covers all topics on Gibbs free energy and electrochemistry up to but not including the Nernst equation (which is all the new material covered in class Weeks 6 and 7). Test 2 starts Tuesday of Week 8.", I believe its only electrochemistry and Gi...
Sun Feb 10, 2019 9:59 pm
Forum: Thermodynamic Definitions (isochoric/isometric, isothermal, isobaric)
Topic: Isothermal meaning
Replies: 4
Views: 122

### Re: Isothermal meaning

Isothermal means that a system stays at a constant temperature
Sun Feb 10, 2019 9:56 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Specific heat
Replies: 3
Views: 95

### Re: Specific heat

Though I wouldn't know whether or not we would be doing it on a midterm/final, you can rearrange equations, such as q=mc(T change), to find the specific heat capacity of a molecule if need be
Sun Feb 10, 2019 9:54 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Topic: Entropy and Enthalpy
Replies: 3
Views: 92

### Re: Entropy and Enthalpy

Usually in equations, S refers to entropy and H refers to enthalpy, you can use that to apply what's given/asked for in the problem and the equations on the equation sheets
Sun Feb 10, 2019 9:50 pm
Forum: Phase Changes & Related Calculations
Topic: Celsius and Kelvin
Replies: 6
Views: 125

### Re: Celsius and Kelvin

However if talking about the temperature itself, Kelvin and Celsius need to be converted from one temperature unit to another depending on what units the equations requires
Sun Feb 10, 2019 9:49 pm
Forum: Phase Changes & Related Calculations
Topic: Celsius and Kelvin
Replies: 6
Views: 125

### Re: Celsius and Kelvin

When talking about a change in temperature, the change in values of Kelvin and Celsius are interchangeable since a one degree difference in Kelvin is the same as a one degree difference in Celsius.
Sun Feb 10, 2019 9:42 pm
Forum: Ideal Gases
Topic: How do I know what is an Ideal Gas
Replies: 11
Views: 229

### Re: How do I know what is an Ideal Gas

There are many conceptual factors to determining if gases are ideal or not, but for the sake of this course I think we are supposed to see every gas as an ideal gas. Many gases do not behave like ideal gases but we havent considered that in class yet
Sun Feb 10, 2019 9:41 pm
Forum: Ideal Gases
Topic: How do I know what is an Ideal Gas
Replies: 11
Views: 229

### Re: How do I know what is an Ideal Gas

An ideal gas is a gas that would take up little to no volume in an area of high temperature and low pressure, and so if a gas behaves enough like an ideal gas, the ideal gas law is applicable
Sun Feb 10, 2019 9:10 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: General entropy question
Replies: 9
Views: 140

### Re: General entropy question

Gasses would have the highest entropy since a molecule can hold more positions in this state, then liquids would have the second highest entropy followed by solids
Sun Feb 10, 2019 9:09 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: General entropy question
Replies: 9
Views: 140

### Re: General entropy question

entropy can be thought of as the ways an object can be positioned in. more complex molecules have more microstate possibilities and therefore they would have a higher entropy.
Tue Jan 22, 2019 10:36 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Exothermic vs Endothermic
Replies: 4
Views: 94

### Re: Exothermic vs Endothermic

It wont automatically favor a certain direction based on whether the equation is endothermic or exothermic, but increasing and decreasing the heat term will cause the reaction to favor a certain side. An endothermic reaction has the heat term on the left side and an exothermic reaction has the heat ...
Tue Jan 22, 2019 10:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Using partial pressure versus molar concentration
Replies: 2
Views: 52

### Re: Using partial pressure versus molar concentration

Yes, your Kp expression would only be including the reactants and products in a gas phase and excluding all solids and liquids
Tue Jan 22, 2019 10:30 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier and water
Replies: 3
Views: 84

### Re: Le Chatelier and water

I believe that water in a gas form would effect the resulting K value. However liquids and solids aren't included in K expressions and therefore have no effect on the K value
Tue Jan 22, 2019 10:24 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Strong acids and bases
Replies: 6
Views: 154

### Re: Strong acids and bases

It wouldn't hurt to memorize some of the strong acids and bases, though you can tell if it is a weak or strong acid by looking at the K value
Tue Jan 22, 2019 10:20 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: ice chart
Replies: 7
Views: 218

### Re: ice chart

For those problems, you are usually given an initial molarity/partial pressure and are asked to find values relating to the equation being at equilibrium
Sun Jan 13, 2019 2:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: True or False regarding reaction mixture [ENDORSED]
Replies: 10
Views: 156

### Re: True or False regarding reaction mixture[ENDORSED]

Yes that is true, both reactions are occurring at equal rates at equilibrium
Sun Jan 13, 2019 2:28 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Gas Phase Reactants and Products
Replies: 2
Views: 37

### Re: Gas Phase Reactants and Products

Because Kc and Kp could both be used for an equation with gas phase reactants and products
Sun Jan 13, 2019 2:25 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Gas Phase Reactants and Products
Replies: 2
Views: 37

### Re: Gas Phase Reactants and Products

It all depends on whether the problem is asking you for an answer in terms of molarity or pressure, for example they may ask you for a Kc or Kp value in the problem
Fri Dec 07, 2018 6:15 pm
Forum: Amphoteric Compounds
Topic: What makes something amphoteric?
Replies: 6
Views: 313

### Re: What makes something amphoteric?

Amphoteric compounds have both basic and acidic character so they can act as either an acid or a base in a reaction, in comparison to a lot of molecules that are labeled as either an acid or base.
Fri Dec 07, 2018 6:10 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Trigonal Bipyramidal
Replies: 6
Views: 190

### Re: Trigonal Bipyramidal

Ethan Breaux 1J wrote:Maybe I'm just reading this wrong but are you referring to see saw?

See saw refers to a molecule with formula AX4E (4 bonds and one lone pair) while T shaped refers to a molecule with formula AX3E2 (3 bonds and two lone pairs)
Fri Dec 07, 2018 6:04 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone Pairs
Replies: 5
Views: 161

### Re: Lone Pairs

Only the bonds and lone pairs on the central atom determine the VSEPR shape of the molecule.
Fri Dec 07, 2018 6:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining polar and non polar molecules from a lewis structure
Replies: 8
Views: 209

### Re: Determining polar and non polar molecules from a lewis structure

This is determined by the symmetry of the molecules and that symmetrical molecules would have dipole moments cancelling each other out. Though often, molecules with lone pairs tend to be polar because the pair’s dipole moment does not cancel out, however there are exceptions to this such as how squa...
Fri Dec 07, 2018 5:57 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: ClO2- lewis structure
Replies: 4
Views: 166

### Re: ClO2- lewis structure

The lewis structure of ClO2- would look like O=Cl-O, where the last O would have a negative charge
Fri Dec 07, 2018 5:54 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs angular?
Replies: 15
Views: 277

### Re: Bent vs angular?

Bent and anglular are two different names for the same kind of VSEPR structure
Fri Dec 07, 2018 5:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: H-bonds
Replies: 4
Views: 125

### Re: H-bonds

Hydrogen bonding is the bond that hydrogen makes to highly electronegative F, O or N. These are more or less great dipole-dipole interactions so they are very polar
Fri Dec 07, 2018 5:49 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent molecular geometry
Replies: 3
Views: 167

### Re: Bent molecular geometry

AX2E2 takes bond angles similar to those of tetrahedral, except the great repulsion of both lone pairs makes the bond angle less than 109.5. AX2E Two lone pairs creates more repulsion than one lone pair
Fri Dec 07, 2018 5:45 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Correct Bond Angles
Replies: 6
Views: 170

### Re: Correct Bond Angles

This usually has to do with the lone pairs and how they create a grear repulsion, which makes bond angles slightly more different than the textbook value. In this case you would write that it is less than the normal bond angle
Fri Dec 07, 2018 5:41 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Central atom
Replies: 5
Views: 149

### Re: Central atom

The atom that has the lowest ionization energy will be at the center, though there are exceptions. For example, hydrogen will never be a central atom
Thu Nov 15, 2018 9:51 pm
Forum: Octet Exceptions
Topic: The center atom
Replies: 20
Views: 660

### Re: The center atom

atoms with the lowest ionization energy tend to be the central atom, and in this case oxygen has the lowest ionization energy. Ionization energy decreases down a group and increases across a period.
Thu Nov 15, 2018 9:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Vespr Formula
Replies: 6
Views: 123

### Re: Vespr Formula

For example, linear would be AX2E0, tetrahedral would be AX4E0, trigonal pyramidal would be AX3E1
Thu Nov 15, 2018 9:35 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Vespr Formula
Replies: 6
Views: 123

### Re: Vespr Formula

The A refers to the central atom, the X refers to the number of bonded atoms, and the E refers to the number of lone pairs
Thu Nov 15, 2018 9:15 pm
Forum: Electronegativity
Topic: Is it best to memorize electronegativity?
Replies: 8
Views: 411

### Re: Is it best to memorize electronegativity?

Usually molecules with lone pairs tend to be polar, ex: trigonal pyramidal has 1 lone pair and is polar, unless the vsepr shape is non-symmetrical and in that case the bond would be non polar despite the lone pairs, ex: square planar has 2 lone pairs and is non-polar because it is symmetrical
Thu Nov 15, 2018 9:12 pm
Forum: Electronegativity
Topic: Is it best to memorize electronegativity?
Replies: 8
Views: 411

### Re: Is it best to memorize electronegativity?

f electronegativity values are given, the difference in electronegativity values is 0.4 or greater, the bond is polar.
Thu Nov 15, 2018 9:01 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Linear Shape
Replies: 5
Views: 126

### Re: Linear Shape

This structure is called bent and the lone pair on the central atom repels the electrons away from the central atom, I'm not sure if we will go over this in class but we learned about this structure in high school and AP chemistry
Thu Nov 15, 2018 8:59 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Linear Shape
Replies: 5
Views: 126

### Re: Linear Shape

Yes, though the shape will be different and would not be called linear
Sat Oct 27, 2018 7:37 pm
Forum: Ionic & Covalent Bonds
Topic: formal charges
Replies: 4
Views: 101

### Re: formal charges

formal charges show the amount of electrons that are in the valence of an electron in an atom. If the formal charge is 0 then the atom is neutral and has the same amount of electrons as protons. A negative number shows that it has that many more electrons than it normally has and a positive number w...
Sat Oct 27, 2018 3:02 pm
Forum: Ionic & Covalent Bonds
Topic: formal charges
Replies: 4
Views: 101

### Re: formal charges

I believe the formal charges will either be given/shown to us in some type of way, otherwise theres a chance he may have us memorize a select few transition metals' charges beforehand.
Fri Oct 26, 2018 3:36 pm
Forum: Trends in The Periodic Table
Topic: Removing 2nd Electron
Replies: 9
Views: 207

### Re: Removing 2nd Electron

Each removal of a valence electron will take more energy than the last and be more difficult. This is due to a concept where it will take more energy to remove an electron from an atom that already has a positive charge because of a higher electrostatic force.
Fri Oct 26, 2018 3:32 pm
Forum: Trends in The Periodic Table
Topic: Ionization Energy
Replies: 6
Views: 151

### Re: Ionization Energy

Down a group there is a greater distance between the nucleus and electrons of an atom because of added energy shells, so because sulphur's electrons are further away from its nucleus than oxygen, it will take less energy to remove an electron from sulphur. The farther an electron is from its nucleus...
Fri Oct 26, 2018 3:22 pm
Forum: Heisenberg Indeterminacy (Uncertainty) Equation
Topic: Indeterminacy Question
Replies: 3
Views: 177

### Re: Indeterminacy Question

The indeterminacy equation involves that delta p and delta t are equal to or greater than plancks constant over 4pi, so the maximum may even be infinite or to a value we cant calculate, but theres at least a minimum value that can be calculated if the equation has an equals sign.
Fri Oct 19, 2018 9:12 pm
Forum: *Shrodinger Equation
Topic: Shrodinger Equation Question
Replies: 3
Views: 129

### Re: Shrodinger Equation Question

We just need to know conceptually how this equation applies to working with orbitals
Fri Oct 19, 2018 9:08 pm
Forum: Properties of Electrons
Topic: eV to J
Replies: 7
Views: 193

### Re: eV to J

The conversion seems to be on the equation sheet that's given to us on tests so we won't need to memorize the conversion
Fri Oct 19, 2018 9:05 pm
Forum: Properties of Light
Topic: Inverse Relationships?
Replies: 4
Views: 98

### Re: Inverse Relationships?

when there are an increased number of oscillations in a certain amount of time (frequency), the distance between the peaks (wavelength) decrease, and vise versa
Thu Oct 11, 2018 8:32 pm
Forum: Properties of Light
Topic: Do I need to memorize the Light Spectrum? [ENDORSED]
Replies: 13
Views: 200

### Re: Do I need to memorize the Light Spectrum?[ENDORSED]

I think it would be better to remember the main ones just in case such as UV light, infrared light, and visible light, and even then just a general idea of where on the spectrum the light is in terms of numbers. Otherwise I'm not sure what information about the light spectrum will be provided on our...
Thu Oct 11, 2018 8:26 pm
Forum: Properties of Light
Topic: Wavelength
Replies: 10
Views: 115

### Re: Wavelength

The answers will probably be in some form of meters, but unless the units are specified I don't think it will matter what kind of unit in meters you use. Being consistent with units is always a better choice though.
Thu Oct 11, 2018 8:19 pm
Forum: Properties of Light
Topic: Light
Replies: 9
Views: 181

### Re: Light

Amplitude and frequency are related in that they are inversely proportional to one another. So, if the amplitude increases, the frequency decreases, or if the amplitude decreases, the frequency increases. This relationship is derived from the equation v = c/(lamda). I believe its the frequency and ...
Thu Oct 04, 2018 6:41 pm
Forum: Significant Figures
Topic: SIG FIGS in ratios
Replies: 4
Views: 244

### Re: SIG FIGS in ratios

using sig figs during your calculations wont necessarily get you a wrong answer, just maybe a slightly less accurate answer. I believe you should just use sig figs at the end of your answer though, that's what I learned in AP Chem. It's especially helpful for when there aren't many sig figs in the q...
Thu Oct 04, 2018 6:22 pm
Forum: SI Units, Unit Conversions
Topic: formula units [ENDORSED]
Replies: 69
Views: 22957

### Re: formula units[ENDORSED]

I believe we dont need to round up the atomic masses in the periodic table, the reason being it would make our calculated answers for problems slightly less accurate than the real answers
Thu Oct 04, 2018 6:12 pm
Forum: Molarity, Solutions, Dilutions
Topic: Q G17 part b. (7th edition)
Replies: 5
Views: 143

### Re: Q G17 part b. (7th edition)

yep, you'd multiply your resulting moles for part b with the molar mass of both the CuSO4 combined with the 5H20, which would be a combined molar mass of 324.65g/mol.