## Search found 57 matches

Tue Mar 12, 2019 12:50 pm
Forum: Second Order Reactions
Topic: amounts of reactant and its affect on rate
Replies: 6
Views: 201

### Re: amounts of reactant and its affect on rate

Yes, that is correct.
Tue Mar 12, 2019 12:49 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Slow Step
Replies: 6
Views: 180

### Re: Slow Step

It should be given.
Tue Mar 12, 2019 12:48 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Intermediates
Replies: 8
Views: 298

### Re: Intermediates

There are never intermediates in a rate law.
Mon Mar 04, 2019 1:47 pm
Forum: General Rate Laws
Topic: 1st and 2nd order
Replies: 6
Views: 321

### Re: 1st and 2nd order

A first-order reaction will be proportional to the change in the initial reaction. So if you multiply one side by two, and the other side doubles as well, you know it's the first order. You also know because when you plug in the equation you will get a decreasing linear graph. If it's a second order...
Mon Mar 04, 2019 1:46 pm
Forum: General Rate Laws
Topic: The value of K
Replies: 5
Views: 168

### Re: The value of K

The k values vary at different temperatures.
Mon Mar 04, 2019 1:45 pm
Forum: General Rate Laws
Topic: 7th Ed. 7A.15
Replies: 2
Views: 115

### 7th Ed. 7A.15

I'm having difficulty calculating the order for C. I found A and B, but I keep getting weird numbers for C. Can anyone explain how to figure that one out?
Wed Feb 27, 2019 3:25 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Order in Cell Diagrams
Replies: 3
Views: 168

### Re: Order in Cell Diagrams

I think either way should work, however I like to write them in order of oxidation or reduction because it makes more sense in my head.
Wed Feb 27, 2019 3:24 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: E^o(cell) vs. Ecell
Replies: 6
Views: 2315

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

E^o is the cell potential in standard conditions. E^cell is when it is in non standard conditions and that's when you use the nernst equation.
Wed Feb 27, 2019 3:23 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Melting/Spontaneous Processes
Replies: 3
Views: 149

### Re: Melting/Spontaneous Processes

Melting would be a forward reaction so delta G is expected to be negative and favorable because it is spontaneous.
Wed Feb 20, 2019 2:43 pm
Forum: Balancing Redox Reactions
Topic: Trends
Replies: 5
Views: 172

### Re: Trends

You can use the periodic table to figure out regular states of molecules, however for transition metals, use the molecules you know to figure out the reaction value of the metal. For example, in SO4 2-. we know oxygen is 2-, multiply by 4 gives us -8. The overall charge is -2 so Sulfur must be +6.
Wed Feb 20, 2019 2:41 pm
Forum: Balancing Redox Reactions
Topic: Galvanic cells
Replies: 4
Views: 157

### Re: Galvanic cells

The reaction will eventually stop because no more ions are flowing through.
Wed Feb 20, 2019 2:40 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Positive vs Negative E value
Replies: 5
Views: 2965

### Re: Positive vs Negative E value

The e value will depend on the overall value of the cell which you get by adding the two half-reactions together to get the overall value.
Mon Feb 11, 2019 5:26 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: Entropy at quilibrium
Replies: 2
Views: 161

### Re: Entropy at quilibrium

At equilibrium, the entropy cannot change any longer and has reached its maximum value.
Mon Feb 11, 2019 5:25 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: When to use differential form
Replies: 2
Views: 148

### Re: When to use differential form

If there is a change in temperature you would use the second equation.
Mon Feb 11, 2019 5:24 pm
Forum: Entropy Changes Due to Changes in Volume and Temperature
Topic: pressure effect on entropy
Replies: 2
Views: 177

### Re: pressure effect on entropy

Since pressure is increasing, that means volume is decreasing, therefore there is less space for molecules to spread out, therefore less entropy.
Mon Feb 04, 2019 3:15 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: qv vs qp
Replies: 9
Views: 435

### Re: qv vs qp

qv is constant volume and qp is constant pressure denoted by the sub letters v and p.
Mon Feb 04, 2019 3:14 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Delta U
Replies: 7
Views: 315

### Re: Delta U

Positive value means an increase in internal energy while a negative one means a decrease.
Mon Feb 04, 2019 3:13 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Equation for internal energy
Replies: 2
Views: 119

### Re: Equation for internal energy

q is the heat transfer from the system to the surroundings.
Tue Jan 29, 2019 11:53 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Calorimetry
Replies: 5
Views: 244

### Re: Calorimetry

Bomb calorimeters keep constant volume while the other kind keeps constant pressure.
Tue Jan 29, 2019 11:52 am
Forum: Heat Capacities, Calorimeters & Calorimetry Calculations
Topic: Cp and Cv
Replies: 3
Views: 138

### Re: Cp and Cv

The R would be the ideal gas constant since you are dealing with gases.
Tue Jan 29, 2019 11:51 am
Forum: Phase Changes & Related Calculations
Topic: Different enthalpy calculation methods
Replies: 4
Views: 149

### Re: Different enthalpy calculation methods

Use the information given in the problem to select the most adequate method to calculate the answer.
Sun Jan 27, 2019 4:20 pm
Forum: Polyprotic Acids & Bases
Topic: Polyprotic Question!
Replies: 12
Views: 1049

### Re: Polyprotic Question!

Polyprotic molecules can donate more than one proton.
Sun Jan 27, 2019 4:19 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: determining x for weak acids and bases
Replies: 6
Views: 414

### Re: determining x for weak acids and bases

If the number is so small you can disregard the x because it will have little effect on the number it's subtracting from. A conjugate acid/base is the molecule formed from an acid or a base.
Sun Jan 27, 2019 4:18 pm
Forum: Acidity & Basicity Constants and The Conjugate Seesaw
Topic: difficulties recognizing weak acids and bases
Replies: 9
Views: 909

### Re: difficulties recognizing weak acids and bases

If you see a Ka or Kb constant that's a giveaway. If not you'll have to draw out the lewis structure and look at the lone pairs to determine if it's a weak acid or base.
Wed Jan 16, 2019 4:49 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Leveled
Replies: 2
Views: 97

### Re: Leveled

A solvent reacts with an acid to make it more neutral and that's why it's "leveled off"
Wed Jan 16, 2019 4:48 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Conjugates
Replies: 5
Views: 222

### Re: Conjugates

The stronger the acid, the weaker the conjugate base and vice versa, that's why it's called a "seesaw" because one is "up" and one is "down" figuratively.
Wed Jan 16, 2019 4:47 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Taking x away in a Ka calculation
Replies: 5
Views: 148

### Re: Taking x away in a Ka calculation

If the x in Ka is so small it's insignificant, (less than 5%) then you can disregard it.
Wed Jan 09, 2019 4:16 pm
Forum: General Science Questions
Topic: Lecture Powerpoints
Replies: 9
Views: 490

### Re: Lecture Powerpoints

No, powerpoints are not posted but Lavelle has other resources on his website like the audiovisual topics on the material we cover in class.
Wed Jan 09, 2019 4:15 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: hw questions - points
Replies: 9
Views: 331

### Re: hw questions - points

Discussion posts count as three points per week, and homework papers count as seven points per week respectively. They are different.
Sat Dec 08, 2018 8:41 pm
Forum: DeBroglie Equation
Topic: test 2 question 3 part C (X-ray)
Replies: 1
Views: 299

### Re: test 2 question 3 part C (X-ray)

It is just the weight of the electron. You use Avogadro's number when pulling molecular weights from the periodic table because the periodic table is in moles per substance and we need grams of a substance.
Sat Dec 08, 2018 8:40 pm
Forum: Bronsted Acids & Bases
Topic: Bronsted Acids and Bases
Replies: 3
Views: 206

### Re: Bronsted Acids and Bases

The molecule is stable and more favorable not giving up it's lone pair, therefore it's a base.
Sat Dec 08, 2018 8:37 pm
Forum: Conjugate Acids & Bases
Topic: Determining Conjugate Acid
Replies: 5
Views: 452

### Re: Determining Conjugate Acid

You add H+ to the acid and subtract it from the base.
Tue Nov 27, 2018 9:17 am
Forum: Dipole Moments
Topic: Polarizability vs Polarizing power
Replies: 8
Views: 315

### Re: Polarizability vs Polarizing power

Polarizability is how easy it to pull an electron from a molecule, and polarizing power is how much the other atom pulls electrons towards it. For example, if one atom is pulling the electrons of another atom in a bond, it has high polarizing power and the other atom has high polarizability.
Tue Nov 27, 2018 9:14 am
Forum: Hybridization
Topic: s-character
Replies: 6
Views: 1034

### Re: s-character

To find s character, just take how many other orbitals there are and find the fraction of s compared to the total. for example sp is 1/2 so 50%, sp2 is 1/3, sp3, is 1/4 so 25%, sp4 is 1/5, etc.
Tue Nov 27, 2018 9:12 am
Forum: *Molecular Orbital Theory (Bond Order, Diamagnetism, Paramagnetism)
Topic: sigma and pi bonds
Replies: 4
Views: 205

### Re: sigma and pi bonds

A pi bond is a nodal plane in the internuclear axis, therefore, it cannot rotate because it is holding together at two points in the nucleus.
Sun Nov 18, 2018 7:17 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Drawing structures
Replies: 8
Views: 357

### Re: Drawing structures

You won't have to draw double bonds or wedges. Just be able to visualize the shape from the given structure.
Sun Nov 18, 2018 7:16 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Molecular geometry vs Electron geometry
Replies: 6
Views: 310

### Re: Molecular geometry vs Electron geometry

I would say assume the geometry since that's what we've been discussing.
Sun Nov 18, 2018 7:15 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: lone pairs and bond angle
Replies: 6
Views: 226

### Re: lone pairs and bond angle

The lone electrons repel each other so they squish the other bonds together making the angle smaller.
Sun Nov 11, 2018 8:35 pm
Forum: Dipole Moments
Topic: Dipole Moments
Replies: 4
Views: 122

### Re: Dipole Moments

Dipole moments are due to the differences in electronegativity between the two atoms. the more negative atom will pull the electrons of the positive one toward it, causing a dipole moment.
Sun Nov 11, 2018 8:34 pm
Forum: Dipole Moments
Topic: Induced-Dipole Induced-Dipole
Replies: 5
Views: 357

### Re: Induced-Dipole Induced-Dipole

Yes they induced dipoles are van der waals and can also be called other names like london forces. They work because they are like a domino effect that occurs due to a force of electrons being moved to one side or becoming denser.
Sun Nov 11, 2018 8:32 pm
Forum: Dipole Moments
Topic: Fluctuation
Replies: 3
Views: 188

### Re: Fluctuation

The fluctuations depend on the density of the electrons as well as how positive the nucleus is, either way they fluctuate because they are repelled by the electrons that are dense around them causing movements.
Sun Nov 04, 2018 8:59 pm
Forum: Lewis Structures
Topic: Formal Charge
Replies: 2
Views: 102

### Re: Formal Charge

WIth ClO you would draw a double bond but ClO- would be a single bond.
Sun Nov 04, 2018 8:57 pm
Forum: Lewis Structures
Topic: Expanded Octet
Replies: 4
Views: 236

### Re: Expanded Octet

The largest atom can make expanded octets because they have more shells.
Sun Nov 04, 2018 8:56 pm
Forum: Lewis Structures
Topic: Double bonds vs. lone pairs
Replies: 5
Views: 588

### Re: Double bonds vs. lone pairs

Arrange the structure with single bonds and calculate the formal charge, then try double bonding and calculate it again. You want to have the formal charge as close to 0 as possible.
Sun Oct 28, 2018 3:01 pm
Forum: Trends in The Periodic Table
Topic: Trends in the periodic table & electron configuration
Replies: 5
Views: 234

### Re: Trends in the periodic table & electron configuration

The electron configurations go in order from left to right on the periodic table. Beginning in row 1, group 1, with hydrogen, it is 1s2, as you move left one it is 2s2, and so on and so forth. You can look to the periodic table to figure out electron configurations quite easily, just remember the tw...
Sun Oct 28, 2018 3:00 pm
Forum: Trends in The Periodic Table
Topic: Diagonal Relationships
Replies: 2
Views: 164

### Re: Diagonal Relationships

I think the most similar elements will be in the same group however metalloids are structured diagonally in the periodic table and share similar properties.
Sun Oct 28, 2018 2:58 pm
Forum: Trends in The Periodic Table
Topic: Removing 2nd e- [ENDORSED]
Replies: 4
Views: 158

### Re: Removing 2nd e-[ENDORSED]

When you remove an election, the atom becomes more positive in the nucleus which means the electrons will be pulled down more since the charge is stronger.
Sun Oct 21, 2018 2:38 pm
Forum: Bohr Frequency Condition, H-Atom , Atomic Spectroscopy
Topic: Differentiating spectroscopies
Replies: 2
Views: 60

### Differentiating spectroscopies

What's the difference between atomic spectroscopy and molecular spectroscopy?
Wed Oct 17, 2018 5:14 pm
Forum: Properties of Light
Topic: energy equation
Replies: 4
Views: 152

### Re: energy equation

You will know depending on the variables given. If the variables don't quite line up with the energy equation, most likely you will have to use the other one and see if that works. Also make sure you distinguish the variable the problem is asking for.
Wed Oct 17, 2018 11:44 am
Forum: Wave Functions and s-, p-, d-, f- Orbitals
Topic: Differentiating Orbitals
Replies: 2
Views: 63

### Differentiating Orbitals

For the s orbital, it only exists on an actual axis, but for the p and d orbitals, they can exist on planes that are on the z-axis? I just need a clearer explanation to distinguish the different between an orbital on an axis vs. an orbital on a plane.
Wed Oct 17, 2018 11:42 am
Forum: Einstein Equation
Topic: Calculating Frequency of Light
Replies: 3
Views: 226

### Re: Calculating Frequency of Light

The values are going to be positive because the light emitted is equal to the energy "lost" by the electron when it dropped levels. Although that may be seen as negative and confusing, it balances out.
Tue Oct 09, 2018 10:05 am
Forum: Limiting Reactant Calculations
Topic: Theoretical vs Actual Yield
Replies: 5
Views: 1678

### Re: Theoretical vs Actual Yield

Theoretical yields will always be greater because it is the best possible outcome in a chemical reaction where nothing went wrong and both substances produced to their full potential. In reality, this never happens so there will always be an incongruence with the actual yield because some substance ...
Tue Oct 09, 2018 10:02 am
Forum: Limiting Reactant Calculations
Topic: Test 1 Question
Replies: 5
Views: 305

### Re: Test 1 Question

Khan Academy has some really good limiting reactant practice problems and they have step by step solutions in case you get stuck. I would also recommend just searching "[topic] practice problems with solutions" and many different options pop up similar to the format in the book. This is ho...
Sun Oct 07, 2018 5:36 pm
Forum: Molarity, Solutions, Dilutions
Topic: Help with G5
Replies: 5
Views: 142

### Re: Help with G5

Can you explain the steps you took to get those answers? I can point out and help with the mistakes you might've made.
Thu Oct 04, 2018 1:30 pm
Forum: SI Units, Unit Conversions
Topic: Converting units in problems
Replies: 3
Views: 183

### Re: Converting units in problems

If there are units in any problem that are not proper SI units that we recognize, for example, mL instead of L, you should always convert it to be safe. Unless the problem specifically asks for that unit always assume you're going to use the SI units.
Wed Oct 03, 2018 8:57 pm
Forum: Limiting Reactant Calculations
Topic: Problem differentiating
Replies: 1
Views: 117

### Problem differentiating

So question, when do you know if it's asking for the limiting reactant vs. % yield? I keep having trouble trying to grasp what some problems are asking from me so I'd like some clarification to keep my eye out for in the future.
Wed Oct 03, 2018 8:52 pm
Forum: Empirical & Molecular Formulas
Topic: problem F13
Replies: 3
Views: 174

### Re: problem F13

Some problems may go more in-depth than others but the steps they take in each individual problem regarding this topic is the same. Just make sure you realize the missing steps, i.e. converting to moles by dividing by each molar masses and you should be good. If anything, look at other problems that...