## Search found 16 matches

Sun Mar 08, 2020 11:18 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: Exothermic vs. Endothermic
Replies: 14
Views: 179

### Re: Exothermic vs. Endothermic

A reaction is exothermic when the energy of the reactants is higher than the energy of the products. The energy difference is what is released into the surroundings as heat. A reaction is endothermic when the energy of the reactants is lower than the energy of the products. The energy difference is ...
Sun Mar 08, 2020 11:15 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Use of Platinum
Replies: 10
Views: 145

### Re: Use of Platinum

Platinum is an inert conductor, so it helps transfer electrons between the anode and cathode when they are both in aqueous solution.
Sun Mar 08, 2020 11:14 pm
Forum: General Rate Laws
Topic: General Rate Laws
Replies: 7
Views: 129

### Re: General Rate Laws

The purpose rate law is to determine the rate of the reaction from reactants to products and relate it to the concentrations of reactions as the reaction progresses.
Sun Mar 08, 2020 11:09 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Test 2
Replies: 7
Views: 150

### Re: Test 2

The more positive half reaction gets reduced, while the more negative half reaction is oxidized. The way I remember it is that the number represents how much a reaction is inclined to be reduced, and the one with the larger value ends up getting reduced.
Sun Mar 08, 2020 11:02 pm
Forum: Reaction Mechanisms, Reaction Profiles
Topic: microscopic reversibility
Replies: 3
Views: 46

### Re: microscopic reversibility

You can assume microscopic reversibility when the rate of the forward reaction and the rate of the reverse reaction are equal during equilibrium.
Sun Mar 01, 2020 9:50 pm
Forum: Appications of the Nernst Equation (e.g., Concentration Cells, Non-Standard Cell Potentials, Calculating Equilibrium Constants and pH)
Topic: Nernst Equation
Replies: 4
Views: 77

### Re: Nernst Equation

The Nernst Equation is used to determine the cell potential under non-standard state conditions. So basically as the cell is progressing through the reaction and the concentrations are changing you can identify the instantaneous potential.
Sun Mar 01, 2020 9:43 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Oxidation Numbers
Replies: 5
Views: 61

### Re: Oxidation Numbers

My tip is to start with oxygens and hydrogens when assigning oxidation numbers. They're pretty much always -2 and +1 respectively. From there, assign numbers to the other elements until the charges cancel out, or they add up to whatever charge the overall molecule has.
Sun Mar 01, 2020 9:40 pm
Forum: Balancing Redox Reactions
Topic: anode/cathod reversible
Replies: 4
Views: 66

### Re: anode/cathod reversible

The reactions in the question are reversible because they are theoretical. But they're asking you to apply those equations in a galvanic cell, and reactions in galvanic cells go to completion. In a different type of question though, you might have to flip one of the reactions so that one is an oxidi...
Sun Mar 01, 2020 9:34 pm
Forum: Work, Gibbs Free Energy, Cell (Redox) Potentials
Topic: n value
Replies: 9
Views: 188

### Re: n value

When you balance half reactions, n is the amount of electrons transferred during the oxidation and reduction half reactions. The number of electrons released by the reducing agent and the amount taken by the oxidizing agent should be the same.
Sun Mar 01, 2020 9:32 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Kinetics vs. thermodynamics
Replies: 4
Views: 85

### Re: Kinetics vs. thermodynamics

Thermodynamics involves equilibrium and stability of reactions, and it's used to convey which direction in a reaction is favored in order to obtain equilibrium. Kinetics involves continuous reactions and observes the change over time.
Sun Feb 16, 2020 11:16 pm
Forum: Balancing Redox Reactions
Topic: How do you combine half reactions together?
Replies: 2
Views: 21

### Re: How do you combine half reactions together?

-You first balance non-oxygen and non-hydrogen atoms in the half-reaction. -Once that is balanced, then add H2O to balance out the oxygen on each side. -Then add H+ to balance the H. -Add equal amounts of OH- on each side to neutralize the H+. -Combine to form H2O (combine on the right side only if ...
Sun Feb 16, 2020 11:08 pm
Forum: Balancing Redox Reactions
Topic: Oxygen
Replies: 9
Views: 107

### Re: Oxygen

The same elements usually have the same oxidation numbers. The periodic table also has trends. Can someone explain the periodic trends please? The elements that are further right will be more electronegative, so their oxidation numbers will be negative, and the number depends on how many electrons ...
Sun Feb 16, 2020 10:59 pm
Forum: General Science Questions
Topic: Studying
Replies: 19
Views: 362

### Re: Studying

Do all of the practice problems, read the textbook, do workshops and office hours. Use whatever resources to make sure you fully understand each topic and are comfortable. You know you got it down once you can explain it to someone else. Also don't cram.
Sun Feb 16, 2020 10:56 pm
Forum: Balancing Redox Reactions
Topic: redox reactions
Replies: 3
Views: 75

### Re: redox reactions

First you have to assign oxidation numbers to each species *An element's oxidation state usually equals the charge of the ion, O is usually -2, and H is usually +1 *Any species without a charge has to have a total number of 0 - take NH3 for example. N has a state of -3, while H has a state of +1: to...
Sun Feb 16, 2020 10:38 pm
Forum: Balancing Redox Reactions
Topic: split equations
Replies: 1
Views: 31

### Re: split equations

The main purpose of splitting equations is to balance the overall redox reaction. You have to separate the reaction into two halves - oxidation and reduction. Once you split it, then it will be easier to balance the electrons lost and the electrons gained to each respective reaction. Once you add th...
Sun Feb 02, 2020 11:17 pm
Forum: Calculating Work of Expansion
Topic: temperature
Replies: 7
Views: 70

### Re: temperature

It simply has to do with the definition of Kelvin when it was created by physicists. [ K = C + 275.15 ]. The difference is that they start at different places. Think of it like a ladder. The very bottom of the Kelvin scale starts at 0 and the bottom of the Celsius scale begins at -273.15 degrees. It...