One way to think of it is that cathode is +, so electrons are being added to it.
The anode is -. so electrons are being removed from it.
The electron from will go from the site being removed (anode) to the site where the electrons are added (cathode).
Search found 31 matches
- Sat Mar 16, 2019 11:33 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Flow of electrons
- Replies: 2
- Views: 122
- Sat Mar 16, 2019 11:32 pm
- Forum: Interesting Applications: Rechargeable Batteries (Cell Phones, Notebooks, Cars), Fuel Cells (Space Shuttle), Photovoltaic Cells (Solar Panels), Electrolysis, Rust
- Topic: Corrosion
- Replies: 2
- Views: 100
Re: Corrosion
You don't need to know the exact processes, just need to be able to understand them if presented to you.
- Sat Mar 16, 2019 11:31 pm
- Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
- Topic: Nerst Equation
- Replies: 3
- Views: 116
Re: Nerst Equation
You will not need to know how to derive it.
- Sat Mar 09, 2019 2:55 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Exothermic and Endothermic Reactions
- Replies: 4
- Views: 166
Re: Exothermic and Endothermic Reactions
If the temperature is increased, the reaction wants to balance out the change of the added energy, so the endothermic process will be favored. If the temperature is decreased, the reaction wants to add energy to balance out its environment so the exothermic process is favored.
- Sat Mar 09, 2019 2:54 pm
- Forum: Ideal Gases
- Topic: sre
- Replies: 5
- Views: 100
Re: sre
You can just think of it as the normal enthaply, except when the conditions of the reactants and products are in the standard state. So it must be in 1 bar and pure states of elements.
- Sat Mar 09, 2019 2:51 pm
- Forum: Ideal Gases
- Topic: ICE Table Values
- Replies: 9
- Views: 228
Re: ICE Table Values
ICE tables can be used to calculate how much a weak acid or base has reacted. It can use moles, molarity, or partial pressure values. Make sure everything is consistent.
- Sun Mar 03, 2019 5:44 pm
- Forum: Balancing Redox Reactions
- Topic: balancing redox reactions
- Replies: 5
- Views: 85
Re: balancing redox reactions
For balancing O, you will always use H2O. For balancing H+, if its acidic, you add H+. If it is a basic solution, you add H2O to the side needing the H+, and add OH- to the other side to balance it out.
- Sun Mar 03, 2019 5:43 pm
- Forum: Balancing Redox Reactions
- Topic: Oxidation number?
- Replies: 12
- Views: 182
Re: Oxidation number?
Group 1 elements have +1. Group 2 elements have +2. Group 17 have -1. Group 16 have -2. The others can vary a bit depending on the element and its state.
- Sun Mar 03, 2019 5:41 pm
- Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
- Topic: Pt(s)
- Replies: 10
- Views: 138
Re: Pt(s)
A solid state conductor is necessary for the cells. When there isn't a solid given, Pt(s) is typically used and thus you must include it in the cell diagram.
- Sat Feb 23, 2019 3:38 pm
- Forum: Concepts & Calculations Using Second Law of Thermodynamics
- Topic: Entropy and mass
- Replies: 2
- Views: 120
Re: Entropy and mass
The more massive a molecule, the more atoms it will typically have and the more states it can be in, resulting in more entropy.
- Sat Feb 23, 2019 3:37 pm
- Forum: Concepts & Calculations Using First Law of Thermodynamics
- Topic: Constants abs Equations Worksheet
- Replies: 2
- Views: 50
Re: Constants abs Equations Worksheet
The equation sheet posted online is the one that will be used for the rest of the tests.
- Sat Feb 23, 2019 3:36 pm
- Forum: Calculating Work of Expansion
- Topic: Nonexpansion work vs expansion work
- Replies: 3
- Views: 158
Re: Nonexpansion work vs expansion work
The simplest way to think about it that expansion work involves volume (something is being expanded) and nonexpansion work is all other types of work
- Sun Feb 17, 2019 11:52 pm
- Forum: Phase Changes & Related Calculations
- Topic: rotational v vibrational energy
- Replies: 5
- Views: 183
Re: rotational v vibrational energy
At room temperature, vibrational energy is negligible. It is the energy of the atoms vibrating in the bonds. Rotational energy is more like the molecule rotating around an axis.
- Sun Feb 17, 2019 11:48 pm
- Forum: Phase Changes & Related Calculations
- Topic: Isothermal
- Replies: 9
- Views: 217
Re: Isothermal
Typically the tests will say isothermal, or temperature constant. Unless explicitly stated, you can assume it is isothermal.
- Sun Feb 17, 2019 11:48 pm
- Forum: Phase Changes & Related Calculations
- Topic: Slope of heating curve
- Replies: 8
- Views: 226
Re: Slope of heating curve
If a substance has a lower heat capacity, that means it will take less energy (x) to make an increase in the temperature (y). This results in a steep slope. Conversely, if a substance has a higher heat capacity, it takes more energy (x) to increase the temperature so it will have a smaller slope.
- Sun Feb 10, 2019 4:37 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Units
- Replies: 6
- Views: 189
Re: Units
There aren't units since they cancel out. Kc will be in brackets, Kp will be in parenthesis, but at the end of the day you only use numbers without anything on them.
- Sun Feb 10, 2019 4:36 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: K constant
- Replies: 5
- Views: 297
Re: K constant
Brackets is for concentration (Kc) whereas the P is for the partial pressure (Kp)
- Sun Feb 10, 2019 4:35 pm
- Forum: Ideal Gases
- Topic: derivatives and integrals
- Replies: 6
- Views: 180
Re: derivatives and integrals
The integral is used to find the work. It's probably best to use the other equation he taught us, the integral was more for deriving the equation.
- Sun Feb 03, 2019 2:35 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: When to use Quadratic equation
- Replies: 10
- Views: 250
Re: When to use Quadratic equation
Typically if the problem involves x^2 and Kc < 10^-3, you must use the quadratic equation to solve.
- Sun Feb 03, 2019 2:34 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: What do do when moles are given
- Replies: 5
- Views: 91
Re: What do do when moles are given
When moles are given you typically use the volume to find the molar concentration, or use it to find the Q value.
- Sun Feb 03, 2019 2:32 pm
- Forum: Ideal Gases
- Topic: atm vs. bar?
- Replies: 23
- Views: 423
Re: atm vs. bar?
Practically you can usually use both but you should definitely use whichever one is specified in the problem.
- Sun Jan 27, 2019 3:11 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: Finding Concentrations of H3O+ and OH-
- Replies: 2
- Views: 90
Re: Finding Concentrations of H3O+ and OH-
As Ibrahim said, [H3O+] is not included in the equation, so we cannot use mole ratios directly to find its concentration. A big mistake that some might do is create some incorrect equation to account for [H3O+] to try and directly solve for it with the initial concentration. We use Kw to solve it be...
- Sun Jan 27, 2019 3:03 pm
- Forum: Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions
- Topic: Change in Pressure caused by Volume
- Replies: 3
- Views: 82
Re: Change in Pressure caused by Volume
Yes, remember that Le Chatelier's principle wants equations to balance out any changes that might occur in the environment. This means that when pressure is increased, the side with the less amount of moles will be favored to try and balance it out. For example, if the products have the smaller amou...
- Sun Jan 27, 2019 2:58 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE problems
- Replies: 5
- Views: 107
Re: ICE problems
Usually you will know in the problem which way the reaction is proceeding. Most of the times it will be the forward reaction that is favored, but occasionally it will be the reverse reaction. Sometimes the concentrations of the products and reactants are given, so you might have to calculate Q and u...
- Sun Jan 20, 2019 3:26 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: How to tell if a chemical is an acid or base?
- Replies: 4
- Views: 89
Re: How to tell if a chemical is an acid or base?
First of all you need to define the type of acid/base you want to check. There are 3 main types: arrhenius, bronsted-lowry, and lewis. ARRHENIUS ACIDS will donate a H+ ion when dissolved in water ARRHENIUS BASES will donate a OH- ion when dissolved in water BRONSTED-LOWRY ACIDS will donate a H+ ion ...
- Sun Jan 20, 2019 3:20 pm
- Forum: Non-Equilibrium Conditions & The Reaction Quotient
- Topic: pKa vs pH?
- Replies: 3
- Views: 89
Re: pKa vs pH?
The simple way to look at is the Ka is the equilibrum concentration and if you take the -log of it, you get the pH. Same for pKb/pOH. To convert it make, simply take the 10^-(pH/pOH) to find the pKa/pKb
- Sun Jan 20, 2019 3:17 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Given Kw
- Replies: 2
- Views: 32
Re: Given Kw
The concentrations of [H3O+] and [OH-] are equal because for water at any temperature, the only molecule you are starting off with is [H2O]. If one of the hydrogens from [H2O] leaves the original molecule and joins another [H2O] molecule, the new molecule becomes [H3O+] and the old one becomes [OH-]...
- Sat Jan 12, 2019 9:35 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE table and cubic expressions
- Replies: 1
- Views: 33
Re: ICE table and cubic expressions
As far as I can tell, Professor Lavelle will not give us any problems with cubic roots to solve on ICE tables. The syllabus only implies that we will be doing problems that only need the quadratic formula to solve. In other scenarios outside the class, the best way to solve more complex chemical equ...
- Sat Jan 12, 2019 9:30 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Solving for K
- Replies: 7
- Views: 89
Re: Solving for K
A simple rule of thumb would be that if the equation involves gases, you use the parenthesis to denote partial pressure, and when the equation involves an aqueous solution, you use the brackets to denote molar concentration. There are exceptions to this rule (particularly the one with gases, as some...
- Sat Jan 12, 2019 9:26 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: ICE Tables
- Replies: 3
- Views: 29
Re: ICE Tables
So you probably already know that the "c" value stands for "change in equilibrium". In most problems, you typically use -x for the reactants, and +x for the products. This gives you an equation for the "e" part of the ICE table, which you can then use the K value to sol...
- Sat Jan 12, 2019 9:23 pm
- Forum: Equilibrium Constants & Calculating Concentrations
- Topic: Kc and Kp
- Replies: 4
- Views: 54
Re: Kc and Kp
Kc is the equilibrium constant for molar concentrations. This is typically used with aqueous solutions, however there are certain times that you would use them with gases (not things you have to worry about right now). Kp is what you should be using to denote the equilibrium constant for gases with ...