## Search found 60 matches

Sun Mar 17, 2019 5:19 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Bimolecular
Replies: 13
Views: 659

### Re: Bimolecular

Molecularity refers to the number of reactants in an elementary reaction so a bimolecular reaction contains two reactants.
Sun Mar 17, 2019 5:17 pm
Forum: Second Order Reactions
Topic: Half Life
Replies: 7
Views: 832

### Re: Half Life

The half lives are provided on the formula sheet.
Sun Mar 17, 2019 5:16 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Plot of Arrhenius function
Replies: 4
Views: 429

### Re: Plot of Arrhenius function

the y axis is lnk as can be seen in the equation lnk= -Ea/RT + lnA
Sun Mar 10, 2019 3:30 pm
Forum: Zero Order Reactions
Topic: Half-life
Replies: 6
Views: 486

### Re: Half-life

The half life of a reactant is simply the time needed for its concentration to fall to 1/2 its initial value.
Sun Mar 10, 2019 3:27 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 2 averages
Replies: 4
Views: 248

### Re: Test 2 averages

I heard the test 2 average was around a 36/50.
Sun Mar 10, 2019 3:27 pm
Forum: Administrative Questions and Class Announcements
Topic: Midterm average
Replies: 5
Views: 275

### Re: Midterm average

I think the midterm average was 80%.
Sun Mar 03, 2019 3:21 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Gibbs Free Energy and Entropy
Replies: 6
Views: 490

### Re: Gibbs Free Energy and Entropy

The sign of delta G is dependent on enthalpy, temperature, and entropy so entropy doesn't necessarily have to be negative; it depends on all three.
Sun Mar 03, 2019 3:13 pm
Forum: Van't Hoff Equation
Topic: units of T
Replies: 5
Views: 401

### Re: units of T

Even if T is given in Celsius, you can just add 273 to get Kelvin but yes you will need to use K in the actual calculation.
Sun Mar 03, 2019 3:10 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell diagrams and solids
Replies: 9
Views: 338

### Re: Cell diagrams and solids

Usually an inert solid like Platinum is added when a solution does not already have a conducting solid.
Sun Feb 24, 2019 12:47 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Spontaneity
Replies: 8
Views: 282

### Re: Spontaneity

When change in Gibbs free energy is negative, the reaction is spontaneous; when delta G is positive, the reaction is not spontaneous.
Sun Feb 24, 2019 12:45 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cathode vs. Anode
Replies: 9
Views: 295

### Re: Cathode vs. Anode

The anode is where oxidation takes place (electrons leave) and the cathode is where reduction takes place (gains electrons).
Sun Feb 24, 2019 12:40 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: test 3
Replies: 10
Views: 368

### Re: test 3

I don't believe it will cover old stuff, but it covers Gibbs free energy and electrochemistry (everything covered in week 6 and 7 lectures).
Sun Feb 17, 2019 3:01 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Enthalpies
Replies: 8
Views: 325

### Re: Bond Enthalpies

Yes, thats right. The bonds broken (reactants) require energy and are endothermic/positive. The bonds formed (products) release energy and are exothermic/negative.
Sun Feb 17, 2019 2:57 pm
Forum: Calculating Standard Reaction Entropies (e.g. , Using Standard Molar Entropies)
Replies: 35
Views: 1168

It should take about a week, so hopefully by the end of week 7.
Sun Feb 17, 2019 1:52 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: state functions and properties
Replies: 11
Views: 2447

### Re: state functions and properties

A state function does not depend on the path taken to achieve that state. This includes density, internal energy, enthalpy, etc.
Sun Feb 10, 2019 6:48 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: midterm
Replies: 5
Views: 200

### Re: midterm

Yes, the midterm covers outlines 1-4 up until entropy; it does not cover Gibbs free energy.
Sun Feb 10, 2019 6:45 pm
Forum: Gibbs Free Energy Concepts and Calculations
Topic: Midterm Next Week
Replies: 6
Views: 219

### Re: Midterm Next Week

The midterm does not cover Gibbs free energy.
Sun Feb 10, 2019 6:44 pm
Forum: Student Social/Study Group
Topic: Lyndon's Review Sess
Replies: 3
Views: 144

### Re: Lyndon's Review Sess

yes, just look up hotdog!
Fri Feb 01, 2019 5:15 pm
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Open, closed, or isolated systems
Replies: 10
Views: 5429

### Re: Open, closed, or isolated systems

open system- matter and energy can exchange with surroundings beaker of water- water can evaporate and breaker does not insulate closed system- energy can exchange with surroundings sealed beaker of water does not insulate isolated system- nothing exchanges with surroundings combustion of glucose in...
Fri Feb 01, 2019 5:10 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Midterm
Replies: 4
Views: 167

### Re: Midterm

The date is listed on the website and is February 13, 6-8pm (week 6).
Fri Feb 01, 2019 5:09 pm
Forum: Ideal Gases
Topic: pV=nRT
Replies: 12
Views: 958

### Re: pV=nRT

This equation shows the relationship between pressure, volume, moles, gas constant, and temperature and can be moved around to find these different values.
Wed Jan 23, 2019 6:39 pm
Forum: Ideal Gases
Topic: Units for concentration
Replies: 5
Views: 186

### Re: Units for concentration

Yes, both of these are equal to one another.
Wed Jan 23, 2019 6:38 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE Table Clarification
Replies: 4
Views: 124

### Re: ICE Table Clarification

When K is less than 10^-3, you can neglect x because it will probably be small enough to where it does not have any significant effect on the calculation.
Wed Jan 23, 2019 6:32 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: ICE boxes
Replies: 5
Views: 190

### Re: ICE boxes

Yes, both can be found using an ICE table.
Fri Jan 18, 2019 12:26 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Le Chatelier's Principle
Replies: 3
Views: 117

### Re: Le Chatelier's Principle

Le Chatelier's principle simply states that chemical reactions adjust so as to minimize the effect of changes. For instance, if more reactant is added, more product will form to account for this change.
Fri Jan 18, 2019 12:18 pm
Forum: Ideal Gases
Topic: Homework Week 2
Replies: 10
Views: 402

### Re: Homework Week 2

Homework is now due in every discussion section.
Fri Jan 18, 2019 12:16 pm
Forum: Ideal Gases
Topic: Chemistry Community Posting
Replies: 7
Views: 256

### Re: Chemistry Community Posting

Post by 11:59 on Sunday night.
Fri Jan 11, 2019 5:14 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Liquids and Solids in Equilibrium Constants
Replies: 5
Views: 189

### Re: Liquids and Solids in Equilibrium Constants

Their effect is not significant enough to be taken into consideration.
Fri Jan 11, 2019 5:11 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Kp
Replies: 9
Views: 302

### Re: Kp

Kp helps specify that the question is asking for partial pressures for gases instead of the equilibrium constant for concentrations.
Fri Jan 11, 2019 5:08 pm
Forum: Ideal Gases
Topic: Q and K [ENDORSED]
Replies: 35
Views: 1677

### Re: Q and K[ENDORSED]

Both Q and K use the same formula.
Thu Dec 06, 2018 12:54 pm
Forum: Hybridization
Topic: tetrahedral
Replies: 5
Views: 216

### Re: tetrahedral

Since there are four areas of electron density, it is sp3.
2=sp 3=sp2 4=sp3 5=sp3d 6=sp3d2
Thu Dec 06, 2018 12:53 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent Structures
Replies: 12
Views: 417

### Re: Bent Structures

Due to the shape, they are polar.
Thu Dec 06, 2018 12:52 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bent vs angular?
Replies: 15
Views: 421

### Re: Bent vs angular?

Bent and angular are the same thing.
Thu Nov 29, 2018 10:37 pm
Forum: Sigma & Pi Bonds
Topic: Sigma bonds
Replies: 6
Views: 318

### Re: Sigma bonds

Sigma bonds overlap side by side.
Thu Nov 29, 2018 10:33 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Determining polar and non polar molecules from a lewis structure
Replies: 8
Views: 383

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

You can usually tell from a lewis structure is a molecule is polar by seeing if they're dipole moments cancel out, which usually happens based off their symmetry.
Thu Nov 29, 2018 10:29 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Dipole moment
Replies: 7
Views: 343

### Re: Dipole moment

Dipole moments depend on polarity and polarity depends on electronegativity, so dipole moments are dependent on these things.
Sat Nov 24, 2018 11:05 pm
Forum: Formal Charge and Oxidation Numbers
Topic: Formal Charge
Replies: 8
Views: 2591

### Re: Formal Charge

Basically the formula can be see as FC= # of valence electrons-( # of dots + # of lines)
the # of dots are just the lone pairs and the # of lines is just the S/2 or number of bonds between atoms
Sat Nov 24, 2018 11:00 pm
Forum: Administrative Questions and Class Announcements
Topic: Test 3
Replies: 10
Views: 462

### Re: Test 3

Yea so it covers the whole Molecular Shape and Structure unit (look at outline 4) and section 2D from the previous Chemical Bonds unit (look at outline 3).
Sat Nov 24, 2018 10:57 pm
Forum: Student Social/Study Group
Topic: curve?
Replies: 20
Views: 1623

### Re: curve?

According to the syllabus, final grades won't be known until the class average is known at the end but there is no curve and a 50% is considered passing with a C-
Sun Nov 18, 2018 6:29 pm
Forum: Administrative Questions and Class Announcements
Topic: Chem Community Posts
Replies: 3
Views: 170

### Re: Chem Community Posts

I'm not sure but I would play it safe and post weekly so you remain active on the website.
Sun Nov 18, 2018 6:28 pm
Forum: Administrative Questions and Class Announcements
Replies: 7
Views: 414

I believe so but he will also adjust the grading scale according to the amount of points people tend to have by the end of the course.
Sun Nov 18, 2018 6:16 pm
Forum: Administrative Questions and Class Announcements
Topic: Thanksgiving week
Replies: 10
Views: 603

### Re: Thanksgiving week

I believe that there is no class on Wednesday.
Sun Nov 11, 2018 12:13 am
Forum: Dipole Moments
Topic: Bond Lengths
Replies: 5
Views: 265

### Re: Bond Lengths

Single bonds are longer than double and triple bonds, however the shorter bonds are the strongest.
Sun Nov 11, 2018 12:12 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: Isoelectronic
Replies: 14
Views: 853

### Re: Isoelectronic

isoelectronic: having the same numbers of electrons or the same electronic structure.
Sun Nov 11, 2018 12:11 am
Forum: Electronegativity
Topic: Electronegativity and Electron Affinity
Replies: 4
Views: 219

### Re: Electronegativity and Electron Affinity

Electron affinity: the energy change when a neutral atom attracts an electron to become a negative ion.
Electronegativity: the ability of an atom in a molecule to draw bonding electrons to itself.
Sun Nov 04, 2018 2:18 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Nodal planes
Replies: 6
Views: 535

### Re: Nodal planes

A nodal plane is where the wave function passes through 0 and the probability of finding an electron there is 0. Essentially the number of nodal planes is equal to l, the angular momentum quantum number.
Sun Nov 04, 2018 2:14 pm
Forum: Electronegativity
Topic: MIDTERM
Replies: 5
Views: 226

### Re: MIDTERM

The Midterm covers Fundamentals, Quantum, Bonding to end of 3.11 (6 Ed.) and to end of 2C (7 Ed) which was up until Wednesday's lecture.
Sun Nov 04, 2018 2:11 pm
Forum: Quantum Numbers and The H-Atom
Topic: Degeneracy
Replies: 6
Views: 472

### Re: Degeneracy

All electrons that have the same value for n are in the same shell. Within a shell (same n), all electrons that share the same l (the angular momentum quantum number, or orbital shape) are in the same sub-shell When electrons share the same n, l, and ml, we say they are in the same orbital (they hav...
Sat Oct 27, 2018 12:03 am
Forum: Quantum Numbers and The H-Atom
Topic: Test #2
Replies: 2
Views: 144

### Re: Test #2

It depends on the question because it could ask for all possible values or just one.
Fri Oct 26, 2018 11:59 pm
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Replies: 5
Views: 243

The number of nodal/radial planes is equal to the value of l. Therefore, s has 0, p has 1, and d has 2.
Fri Oct 26, 2018 11:56 pm
Forum: Einstein Equation
Topic: E=hv
Replies: 43
Views: 4496

### Re: E=hv

E represents the energy of the photon, while the work function is the minimum energy needed to remove an electron.
Fri Oct 19, 2018 8:27 pm
Topic: Test
Replies: 9
Views: 756

### Re: Test

I believe he said that we would not need to know about black body radiation.
Fri Oct 19, 2018 8:25 pm
Forum: Properties of Light
Topic: Inverse Relationships?
Replies: 4
Views: 188

### Re: Inverse Relationships?

In the equation (c)=wavelength(lambda) x frequency(v), the speed (c) is a constant. Therefore if wavelength increases, frequency must decrease and vice versa because c must remain the same.
Fri Oct 19, 2018 8:21 pm
Forum: Photoelectric Effect
Topic: Test 2
Replies: 16
Views: 535

### Re: Test 2

I believe this test will only cover the quantum world section, however, it may be useful to remember and apply content from the previous section.
Sat Oct 13, 2018 3:03 pm
Forum: Limiting Reactant Calculations
Topic: Test 1
Replies: 5
Views: 362

### Re: Test 1

I'm pretty sure our TA said there will be partial credit and that being off a few significant figures won't matter much.
Sat Oct 13, 2018 3:01 pm
Forum: SI Units, Unit Conversions
Topic: mol vs. mmol
Replies: 12
Views: 844

### Re: mol vs. mmol

The prefix "milli" represents a factor of 10^-3, so a mmol Is 10^-3 mol.
Sat Oct 13, 2018 2:58 pm
Forum: Limiting Reactant Calculations
Topic: Test 1
Replies: 5
Views: 541

### Re: Test 1

The TA said we will be getting scores in discussion, I don't think there is any way to get them before that.
Sun Oct 07, 2018 4:39 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: Percision and Accuracy
Replies: 5
Views: 310

### Re: Percision and Accuracy

If you were trying to pour exactly 5 mL of water in a beaker and the first three times you poured 5, 5.1, and 4.9, then your accuracy and precision is pretty high because it's close to 5 and the numbers are close together. Precision is related to repeatability so if the next three times you poured 5...
Sun Oct 07, 2018 4:34 pm
Forum: SI Units, Unit Conversions
Topic: Formula Sheet?
Replies: 6
Views: 255

### Re: Formula Sheet?

I believe we just get the periodic table so I would be safe and memorize the main formulas we have been working with. However, you can always ask or email the TA.
Sun Oct 07, 2018 4:31 pm
Forum: Empirical & Molecular Formulas
Topic: When to double moles
Replies: 13
Views: 445

### Re: When to double moles

If the number is within about .1, then round to the nearest whole number.