Search found 62 matches

by Rhea Churi 4K
Thu Mar 14, 2019 11:19 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: catalyst or intermediate
Replies: 3
Views: 15

Re: catalyst or intermediate

Catalyst is there in the beginning of the reaction and is then used up and recreated.
Intermediate is created and then used up.
by Rhea Churi 4K
Thu Mar 14, 2019 11:13 pm
Forum: General Rate Laws
Topic: slow/fast steps
Replies: 7
Views: 25

Re: slow/fast steps

Yeah it should be given.
by Rhea Churi 4K
Thu Mar 14, 2019 11:09 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: A in the Arrhenius Equation
Replies: 4
Views: 18

Re: A in the Arrhenius Equation

It gives the frequency at which the reactants collide correctly to form products.
I'm pretty sure for this class A will either be given or just equal to 1.
by Rhea Churi 4K
Thu Mar 14, 2019 11:08 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Catalysts in Rate Law
Replies: 5
Views: 20

Re: Catalysts in Rate Law

Yes, catalysts can be included in the rate law.
by Rhea Churi 4K
Thu Mar 14, 2019 11:07 pm
Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
Topic: Adding an Inert Gas
Replies: 4
Views: 23

Re: Adding an Inert Gas

An inert gas is not reactive so it doesn't affect the reaction at all.
by Rhea Churi 4K
Thu Mar 14, 2019 11:01 pm
Forum: General Rate Laws
Topic: Final
Replies: 9
Views: 45

Re: Final

It'll probably be pretty strict because thermodynamics and kinetics require specific units.
by Rhea Churi 4K
Thu Mar 14, 2019 10:58 pm
Forum: Method of Initial Rates (To Determine n and k)
Topic: Units of k
Replies: 5
Views: 20

Re: Units of k

Zero-order reaction is mol L-1 s-1
First-order reaction is s-1
Second-order reaction is L mol-1 s-1.
by Rhea Churi 4K
Thu Mar 14, 2019 10:49 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: When to use quadratic equation
Replies: 2
Views: 9

Re: When to use quadratic equation

Quadratic formulas are usually used with ICE tables, when you don't know the concentration of 1 or more of the reactants or products.
by Rhea Churi 4K
Thu Mar 14, 2019 10:46 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: catalyst vs intermediate
Replies: 9
Views: 37

Re: catalyst vs intermediate

Catalyst is there in the beginning of reaction and is then recreated later on. An intermediate is created and used up during the reaction.
by Rhea Churi 4K
Thu Mar 14, 2019 9:00 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: Ranking species
Replies: 3
Views: 34

Re: Ranking species

More positive E value means it will have a higher oxidizing power.
More negative E value means it will have a higher reducing power.
by Rhea Churi 4K
Thu Mar 14, 2019 3:46 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Rate laws
Replies: 2
Views: 20

Re: Rate laws

No, catalysts only influence a reaction rate. They do not appear in the rate law.
by Rhea Churi 4K
Thu Mar 14, 2019 3:44 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Intermediate vs catalyst
Replies: 8
Views: 42

Re: Intermediate vs catalyst

Intermediate is created and then used up throughout the steps.
A catalyst is there when the reaction begins and is then recreated later on.
by Rhea Churi 4K
Thu Mar 14, 2019 1:26 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Expansion of a system
Replies: 7
Views: 78

Re: Expansion of a system

Volume increases and system does work are ways to tell if expansion is happening.
by Rhea Churi 4K
Thu Mar 14, 2019 1:24 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Internal energy (U) of an isolated system
Replies: 17
Views: 140

Re: Internal energy (U) of an isolated system

An isolated system cannot exchange matter or energy so there is no change.
by Rhea Churi 4K
Thu Mar 14, 2019 1:16 pm
Forum: Calculating Work of Expansion
Topic: Work without change in volume
Replies: 8
Views: 73

Re: Work without change in volume

No change in volume means no work is done.
by Rhea Churi 4K
Thu Mar 14, 2019 1:13 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Catalysts
Replies: 6
Views: 36

Re: Catalysts

A catalyst is there in the beginning of the reaction and is then recreated at a later step of the reaction.
by Rhea Churi 4K
Thu Mar 14, 2019 1:11 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst
Replies: 14
Views: 63

Re: Nernst

Yup, you find total e- after you balance the reaction.
by Rhea Churi 4K
Thu Mar 14, 2019 1:10 pm
Forum: Balancing Redox Reactions
Topic: How to tell if its in acidic or basic
Replies: 6
Views: 38

Re: How to tell if its in acidic or basic

Going off of test 2, they usually tell you if it is an acidic or basic solution.
by Rhea Churi 4K
Thu Mar 14, 2019 1:03 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: deltaU=0
Replies: 1
Views: 15

Re: deltaU=0

DeltaU can be zero if q and w=0 or q=w (isothermal).
by Rhea Churi 4K
Thu Mar 14, 2019 12:58 pm
Forum: Thermodynamic Systems (Open, Closed, Isolated)
Topic: Adiabatic and isothermal
Replies: 6
Views: 37

Re: Adiabatic and isothermal

Adiabatic: q=0
Isothermal: T=0
by Rhea Churi 4K
Thu Mar 14, 2019 12:48 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Determining Catalysts from Diagrams (7E.5)
Replies: 3
Views: 19

Re: Determining Catalysts from Diagrams (7E.5)

A catalyst is used up in the beginning of the reaction and then recreated.
An intermediate is created and then used up.
by Rhea Churi 4K
Thu Mar 14, 2019 12:44 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Pseudo Equilibrium Constant
Replies: 1
Views: 23

Re: Pseudo Equilibrium Constant

It tells you the order of the reaction for one reactant, but it is pseudo because you had to put another reactant in excess to figure it out.
by Rhea Churi 4K
Thu Mar 14, 2019 12:41 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagram Order
Replies: 2
Views: 27

Re: Cell Diagram Order

Anode is always on the left and the cathode is on the right so:

Anode electrode|Oxidation reaction||Reduction reaction|Cathode electrode
by Rhea Churi 4K
Thu Mar 14, 2019 12:35 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Bimolecular
Replies: 13
Views: 62

Re: Bimolecular

Athena L 1B wrote:So is a bimolecular reaction another way of saying it's second order?

A bimolecular reaction is always a second order reaction but not all second order reactions are bimolecular.
by Rhea Churi 4K
Thu Mar 14, 2019 12:33 pm
Forum: Biological Examples
Topic: biological examples for final
Replies: 5
Views: 50

Re: biological examples for final

Each chapter in the textbook that we need to know has a brief section on the biological applications, so it would probably be helpful to review those.
by Rhea Churi 4K
Thu Mar 14, 2019 12:31 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Activation Energy
Replies: 7
Views: 43

Re: Activation Energy

Activation energy is the energy required to cause a reaction to happen. It is represented by the highest peak on an energy graph.
by Rhea Churi 4K
Thu Mar 14, 2019 12:29 pm
Forum: General Rate Laws
Topic: k1 vs k2?
Replies: 4
Views: 23

Re: k1 vs k2?

K changes when it is a different reaction or the same reaction is performed at a different temperature.
by Rhea Churi 4K
Thu Mar 14, 2019 12:26 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: collision theory
Replies: 2
Views: 23

Re: collision theory

I don't think so, it didn't show up on any of the outlines
by Rhea Churi 4K
Thu Mar 14, 2019 12:24 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: comparing forward and reverse rates
Replies: 4
Views: 27

Re: comparing forward and reverse rates

Constants are different from the rate at which the reaction proceeds, so K values are not equal but the rates are.
by Rhea Churi 4K
Sun Jan 13, 2019 5:59 pm
Forum: Ideal Gases
Topic: Pv=nRT [ENDORSED]
Replies: 12
Views: 131

Re: Pv=nRT [ENDORSED]

Emily Kennedy 4L wrote:we only use this equation to convert from partial pressure to concentration and vice versa rt?

Yes, you would use P/RT=Concentration
by Rhea Churi 4K
Sun Jan 13, 2019 5:55 pm
Forum: Non-Equilibrium Conditions & The Reaction Quotient
Topic: reaction quotient [ENDORSED]
Replies: 4
Views: 41

Re: reaction quotient [ENDORSED]

Jaira_Murphy_2D wrote:Is the reaction quotient unit-less as well?

Yes the reaction quotient is unit-less
by Rhea Churi 4K
Sun Jan 13, 2019 5:53 pm
Forum: Equilibrium Constants & Calculating Concentrations
Topic: Constants using pressure or concentration
Replies: 2
Views: 18

Re: Constants using pressure or concentration

Most likely, you use concentration for calculating K. However, you will be able to find out whether to use pressure or concentration if it is denoted K(p) for pressure or K(c) for concentration.
by Rhea Churi 4K
Fri Dec 07, 2018 12:28 pm
Forum: Naming
Topic: Coordination Compounds on the Final
Replies: 2
Views: 26

Re: Coordination Compounds on the Final

I would memorize them just to be safe. Definitely know EN and EDTA.
by Rhea Churi 4K
Fri Dec 07, 2018 12:19 pm
Forum: Calculating the pH of Salt Solutions
Topic: pH sig figs
Replies: 4
Views: 44

Re: pH sig figs

My TA said to follow the decimal rule. Count sig figs after the decimal.
by Rhea Churi 4K
Fri Dec 07, 2018 12:18 pm
Forum: Bronsted Acids & Bases
Topic: Question on Acidity
Replies: 1
Views: 21

Re: Question on Acidity

It leans more towards size. HF is very electronegative but very small. Because it is so small, it doesn't handle the negative charge very well, making it unstable. So, H2Se would be stronger than HF because Se can handle its charge better.
by Rhea Churi 4K
Sun Dec 02, 2018 4:48 pm
Forum: Administrative Questions and Class Announcements
Topic: Final [ENDORSED]
Replies: 5
Views: 123

Re: Final [ENDORSED]

As of right now, I don't think there is a practice final. I think at the review sessions they're going to hand out practice problems.
by Rhea Churi 4K
Sun Dec 02, 2018 4:33 pm
Forum: Lewis Acids & Bases
Topic: acid names
Replies: 8
Views: 72

Re: acid names

I think we definitely need to know the formula for acetic acid and know strong acids as well.
by Rhea Churi 4K
Sun Dec 02, 2018 4:18 pm
Forum: Calculating pH or pOH for Strong & Weak Acids & Bases
Topic: Final pH
Replies: 3
Views: 38

Re: Final pH

Also, pOH measures the concentration of OH- in solution. Because we evaluate on a pH scale, you need to subtract it from 14
by Rhea Churi 4K
Mon Nov 19, 2018 5:06 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles
Replies: 3
Views: 38

Re: Bond Angles

It's less than 90 and 120 degrees.
by Rhea Churi 4K
Mon Nov 19, 2018 4:43 pm
Forum: Hybridization
Topic: Hybridized Orbitals
Replies: 4
Views: 44

Re: Hybridized Orbitals

The s and p orbital combined only make up 4 areas of electron density. However, as we've seen a molecule can have more than that. Thus, the d orbital gets involved because it contributes electrons while bonding and can be part of a hybrid orbital.
by Rhea Churi 4K
Mon Nov 19, 2018 4:41 pm
Forum: Hybridization
Topic: Labeling Compounds
Replies: 4
Views: 35

Re: Labeling Compounds

Because there are only 3 p orbitals that exist and can be filled and s also contributes an orbital, so there is a total of 4 areas of electron density/orbitals
by Rhea Churi 4K
Sun Nov 18, 2018 10:08 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Lone pairs
Replies: 5
Views: 53

Re: Lone pairs

Yes, lone pairs change the shape by changing bond angles so the name changes as well.
by Rhea Churi 4K
Sun Nov 18, 2018 10:03 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Bond Angles for H2O
Replies: 8
Views: 56

Re: Bond Angles for H2O

This is because the molecule is polar so the positive side (H atoms) are drawn towards negative side (O and lone pairs) making the angle smaller.
by Rhea Churi 4K
Sun Nov 18, 2018 10:00 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: Polar/Nonpolar
Replies: 3
Views: 55

Re: Polar/Nonpolar

In CH2Cl2, the 2 bonds create a dipole towards the Cl since it is electronegative. This makes the molecule negative towards the Cl and away from the 2 H.
by Rhea Churi 4K
Sun Nov 11, 2018 8:30 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: molecular shapes
Replies: 13
Views: 134

Re: molecular shapes

He'll go over them most likely but eventually we'll have to know shape, name, bond angle, and hoe to draw molecules with up to 6 bonds.
by Rhea Churi 4K
Sun Nov 11, 2018 8:24 pm
Forum: Determining Molecular Shape (VSEPR)
Topic: tetrahedral
Replies: 3
Views: 39

Re: tetrahedral

It is because molecules exist in the 3d world. Because of that, the atoms want to be far from each other as possible because of electron repulsion so the bind angle is 109.5 degrees.
by Rhea Churi 4K
Sun Nov 04, 2018 6:18 pm
Forum: Ionic & Covalent Bonds
Topic: Naming Ionic Compounds
Replies: 5
Views: 56

Re: Naming Ionic Compounds

There isn't anything about naming because we haven't gone over it yet.
by Rhea Churi 4K
Sun Nov 04, 2018 6:14 pm
Forum: Lewis Structures
Topic: Expanded Octet
Replies: 4
Views: 50

Re: Expanded Octet

Yes, Iodine is larger and has more orbitals, so it has more electrons to make bonds.
by Rhea Churi 4K
Sun Nov 04, 2018 4:52 pm
Forum: Ionic & Covalent Bonds
Topic: Midterm questions
Replies: 5
Views: 64

Re: Midterm questions

All the way up to 3.11 in 6th edition and 2C in the 7th.
by Rhea Churi 4K
Sun Oct 28, 2018 5:05 pm
Forum: Ionic & Covalent Bonds
Topic: Ionic Bonds vs Covalent Bonds
Replies: 7
Views: 129

Re: Ionic Bonds vs Covalent Bonds

Ionic bonds also tend to make lattice structures that are very hard to break, making the bond stronger.
by Rhea Churi 4K
Sun Oct 28, 2018 4:56 pm
Forum: Resonance Structures
Topic: Resonance Structures
Replies: 5
Views: 121

Re: Resonance Structures

What are some examples of resonance structures? Do they only occur in bonds between certain molecules? Resonance structures are used when one Lewis structure for a single molecule cannot fully describe the bonding that takes place. Polyatomic icons usually have resonance structures, like nitrate fo...
by Rhea Churi 4K
Sun Oct 28, 2018 4:48 pm
Forum: Ionic & Covalent Bonds
Topic: Unit of Atomic Radius
Replies: 4
Views: 40

Re: Unit of Atomic Radius

It is most commonly measured in Angstroms.
by Rhea Churi 4K
Sun Oct 28, 2018 4:45 pm
Forum: Ionic & Covalent Bonds
Topic: Covalent Bonds
Replies: 7
Views: 92

Re: Covalent Bonds

Nonmetals tend to have higher electronegativity. So they attract more electrons, making it easier to form anions.
by Rhea Churi 4K
Sun Oct 28, 2018 4:41 pm
Forum: Lewis Structures
Topic: Ground State e- Configuration
Replies: 3
Views: 44

Re: Ground State e- Configuration

Atoms typically seek to fill each energy level before moving onto the next one as it helps with stability. Thus, Ag would fill up the 4d energy level before moving up.
by Rhea Churi 4K
Sun Oct 28, 2018 4:36 pm
Forum: Ionic & Covalent Bonds
Topic: the Octet rule
Replies: 21
Views: 186

Re: the Octet rule

Usually, most atoms try to follow the octet rule. However, there are cases where 1) molecules have an odd number of electrons (ex. NO), 2) two few valence electrons result in an incomplete octet usually common w boron, aluminum, and beryllium (ex. BH3), or 3) expanded octets - molecules possess more...
by Rhea Churi 4K
Sun Oct 14, 2018 2:50 pm
Forum: Accuracy, Precision, Mole, Other Definitions
Topic: diatomic elements
Replies: 12
Views: 310

Re: diatomic elements

Karina Jiayu Xu 4E wrote:Does anyone know what order to put the elements in when writing an empirical formula?


In an empirical formula, it's typically C, H, and then other elements follow in alphabetical order.
by Rhea Churi 4K
Sun Oct 14, 2018 2:45 pm
Forum: Properties of Electrons
Topic: Wave Length Calculations
Replies: 5
Views: 51

Re: Wave Length Calculations

Conservatively, 10^-18 is when it becomes too small to notice.
by Rhea Churi 4K
Sun Oct 14, 2018 2:43 pm
Forum: Properties of Light
Topic: Geiger and Marsden experiment
Replies: 3
Views: 31

Re: Geiger and Marsden experiment

Geiger and Marsden performed a series of experiments where they pointed a beam of alpha particles at a thin foil of metal and measured the scattering pattern by using a fluorescent screen. They spotted alpha particles bouncing off the metal foil in all directions, some right back at the source. They...
by Rhea Churi 4K
Thu Oct 04, 2018 5:59 pm
Forum: Empirical & Molecular Formulas
Topic: Homework Problem F.3 (part a)
Replies: 2
Views: 58

Re: Homework Problem F.3 (part a)

Nitric Acid is HNO3 Usually, when something is an acid it contains an H+ ion. Because it is Nitric, that means it has an NO3- ion (because it ends in "-ic" that means the ion itself ends in "-ate", so a nitrate ion). I'm pretty sure Dr. Lavelle said we would be learning how to na...
by Rhea Churi 4K
Thu Oct 04, 2018 5:32 pm
Forum: SI Units, Unit Conversions
Topic: HW E.9
Replies: 3
Views: 118

Re: HW E.9

I'm pretty sure for now Dr. Lavelle said he would give us the formula but we'll be learning how to name them and find their formulas pretty soon.
Magnesium sulfate heptahydrate would be MgSO4 * 7(H2O)
Hope this helps!
by Rhea Churi 4K
Thu Oct 04, 2018 5:19 pm
Forum: Empirical & Molecular Formulas
Topic: Molecular Formulas
Replies: 5
Views: 89

Re: Molecular Formulas

Because it's asking you to find the atom ratios, you're basically trying to find the empirical formula. You would assume that you have 100 g of Vanillin so you can convert each percent composition to grams, giving you the mass. So, 63.15% C would be 63.15 g C, and so on and you would convert it to m...

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