## Search found 33 matches

Sun Mar 18, 2018 6:20 pm
Forum: General Rate Laws
Topic: rate law
Replies: 6
Views: 468

### Re: rate law

no rate laws don't include products you are thinking of the equilibrium constant
Sun Mar 18, 2018 6:19 pm
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Transition State
Replies: 3
Views: 252

### Re: Transition State

It is the peak because it has the highest energy since the carbons have 5 bonding groups around them during that small amount of time, making it highly unstable
Sun Mar 18, 2018 6:17 pm
Forum: First Order Reactions
Topic: k' in Pseudo-First-Order Rate Laws
Replies: 4
Views: 576

### Re: k' in Pseudo-First-Order Rate Laws

k' stands for k*the reactants that you don't use in the rate law
Tue Mar 13, 2018 11:16 am
Forum: Second Order Reactions
Topic: Half life
Replies: 6
Views: 321

### Re: Half life

it is 1/(1/16) making it 16/1 (it flips); just plug it into the equation and you should be fine
Tue Mar 13, 2018 11:15 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: How does a homogeneous catalyst affect (a) the rate law; (b) the equilibrium constant? [ENDORSED]
Replies: 5
Views: 245

### Re: How does a homogeneous catalyst affect (a) the rate law; (b) the equilibrium constant?[ENDORSED]

part a increases because catalysts increase the rate of the reaction in general
Tue Mar 13, 2018 11:12 am
Forum: Arrhenius Equation, Activation Energies, Catalysts
Topic: Homogeneous Catalysts
Replies: 3
Views: 167

### Re: Homogeneous Catalysts

its just an observed trait
Tue Mar 06, 2018 10:57 am
Forum: General Rate Laws
Topic: Concentration and Rate Relationship
Replies: 4
Views: 160

### Re: Concentration and Rate Relationship

for multiple reactions, see the effect of each reactant on the rate. so if one reactant is 1st order and another is 2nd order, the 1st would double the rate if the concentration is doubled and the 2nd one would quadruple the rate if the concentration was doubled. you usually view them separately lik...
Tue Mar 06, 2018 10:55 am
Forum: General Rate Laws
Topic: How the concentration of a reactant affects the rate of the reaction
Replies: 3
Views: 108

### Re: How the concentration of a reactant affects the rate of the reaction

depending on order, raise the effect on the concentration to that power to see the effect on the rate. for example if we double the concentration of a 1st order than you do 2^1 (1 because 1st order) which equals 2 meaning the rate will also be doubled. for 2nd order it would be 2^2 meaning the rate ...
Tue Mar 06, 2018 10:52 am
Forum: General Rate Laws
Topic: When to Use Avg. vs Instantaneous
Replies: 5
Views: 132

### Re: When to Use Avg. vs Instantaneous

you can also usually tell by what is given in the problem. for example if it doesn't give an order but gives you a rate then its most likely average rate instead of instantaneous
Tue Feb 27, 2018 10:03 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: signs
Replies: 6
Views: 521

### Re: signs

we dont want to be talking about "negative" rates so we add the negative when talking about the rates of the reactants since they are decreasing and their rate would normally be negative (adding the negative makes it positive, which we want, this also represents rate of products)
Tue Feb 27, 2018 10:01 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: units of the rate of reaction
Replies: 7
Views: 384

### Re: units of the rate of reaction

theres a pattern to it as you can see in the previous responses so for 2nd reaction the L and mol gets raised to 2nd power and 3rd reaction gets raised to 3rd power and so on; seconds remain just seconds
Tue Feb 27, 2018 9:59 pm
Forum: Kinetics vs. Thermodynamics Controlling a Reaction
Topic: Slowest Elementary Step
Replies: 4
Views: 141

### Re: Slowest Elementary Step

We need the longest time taken for products to be formed or else that slowest step would not be able to be completed; if the slowest step takes 10 seconds but every other step only takes 1, you still need to give the reaction 10 seconds to complete that slow step
Fri Feb 23, 2018 2:14 pm
Forum: Galvanic/Voltaic Cells, Calculating Standard Cell Potentials, Cell Diagrams
Topic: Cell Diagrams [ENDORSED]
Replies: 7
Views: 256

### Re: Cell Diagrams[ENDORSED]

they are inert so that they will not change the reaction but will act as electron transporters to allow the redox reaction to occur
Fri Feb 23, 2018 2:05 pm
Forum: Balancing Redox Reactions
Topic: Reaction E [ENDORSED]
Replies: 5
Views: 174

### Re: Reaction E[ENDORSED]

E values never change, even if the chemical reaction is being multiplied by a factor
Fri Feb 23, 2018 2:03 pm
Forum: Balancing Redox Reactions
Topic: Cell Diagram [ENDORSED]
Replies: 7
Views: 229

### Re: Cell Diagram[ENDORSED]

The only time they aren't going to be separated by lines is when they are both the same state such as two aqueous solutions
Sun Feb 18, 2018 4:11 pm
Forum: Balancing Redox Reactions
Topic: Balancing Redox reactions
Replies: 3
Views: 127

### Re: Balancing Redox reactions

you need to balance O first because you will only know how much H you need once you get the right amount of O
Sun Feb 18, 2018 4:09 pm
Forum: Balancing Redox Reactions
Topic: agents
Replies: 3
Views: 124

### Re: agents

an agent is just the thing that does the action so for an oxidizing agent it is the thing that does the oxidizing
Sun Feb 18, 2018 4:07 pm
Forum: Phase Changes & Related Calculations
Topic: Specific heat of water or ice?
Replies: 6
Views: 215

### Re: Specific heat of water or ice?

I get confused with this a lot to but you just have to know that under 0 degrees Celsius will be ice and above will be water and if its at 0 degrees it will usually tell you what current state its in
Wed Feb 07, 2018 3:28 pm
Forum: Balancing Redox Reactions
Topic: Ozone oxidation number
Replies: 2
Views: 83

### Re: Ozone oxidation number

O3 is a neutral substance so it's oxidation number is 0 (there is no negative or positive charge on the compound)
Wed Feb 07, 2018 3:25 pm
Forum: Balancing Redox Reactions
Topic: Transition Metals
Replies: 4
Views: 136

### Re: Transition Metals

you basically need to rely on the other element in the compound as Audrey said to determine the oxidation state in that situation
Wed Feb 07, 2018 3:23 pm
Forum: Balancing Redox Reactions
Topic: oxidation
Replies: 4
Views: 149

### Re: oxidation

you essentially look at the elements location in the periodic table. if it is in the first two groups, it will be +1 and +2 (the group number) and if it is in the last couple of groups, it will be -3, -2, -1 (corresponding to group 15, 16, 17)
Sun Feb 04, 2018 5:56 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: The sign of the change in Gibb's Free Energy
Replies: 6
Views: 187

### Re: The sign of the change in Gibb's Free Energy

when deltaG is negative, that means deltaS of the universe (total) is positive since deltaS(total)=-(deltaG)/T. deltaS being positive means the reaction is spontaneous (thus deltaG needs to be negative)
Sun Feb 04, 2018 5:47 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: Test Number 1
Replies: 9
Views: 304

### Re: Test Number 1

doing work while maintaining a constant temp needs to include a heat transfer in order to maintain the constant temperature (q=-w or w=-q)
Sun Feb 04, 2018 5:44 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: q=-w [ENDORSED]
Replies: 5
Views: 206

### Re: q=-w[ENDORSED]

This formula is true for instances of isothermal expansions since having deltaT=0 (no change in temp), then deltaU (internal energy) would be 0 and since deltaU=q+w, then q would equal -w
Sun Jan 28, 2018 5:51 pm
Forum: Concepts & Calculations Using First Law of Thermodynamics
Topic: isothermal system
Replies: 3
Views: 172

### Re: isothermal system

The important part is isothermal, meaning deltaT would be 0 making deltaU 0 (since anything *0=0).
Sun Jan 28, 2018 5:37 pm
Forum: Concepts & Calculations Using Second Law of Thermodynamics
Topic: Spontineity
Replies: 5
Views: 156

### Re: Spontineity

Also spontaneous reactions with gas can't occur while going to a smaller volume because that would require energy but larger volume wouldn't need anything to happen
Sun Jan 28, 2018 5:22 pm
Forum: Calculating Work of Expansion
Topic: The integral equation
Replies: 8
Views: 234

### Re: The integral equation

I also don't believe we will actually have to derive anything on the tests because it isn't the point of the equation. We only derived it to help us understand where it came from.
Thu Jan 18, 2018 10:23 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bong Enthalpy accuracy [ENDORSED]
Replies: 3
Views: 118

### Re: Bong Enthalpy accuracy[ENDORSED]

I think when we are given the question, there will be only one method that fits the question so I don't think you would have much of a choice to not use this method but it is just worth knowing that this method is the least accurate.
Thu Jan 18, 2018 10:20 am
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Bond Breaking or forming
Replies: 5
Views: 149

### Re: Bond Breaking or forming

In response to your latest question, you would just notice that a bond in the reactants had been broken and a new bond in the products is formed because there are different combinations. For example, if we have CH4 + HBr --- CH4Br and we drew the lewis structures, we would see that the double carbon...
Mon Jan 15, 2018 3:10 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: HW Ch.8 #59 and 63
Replies: 7
Views: 293

### Re: HW Ch.8 #59 and 63

I am confused about this as well because in both questions 59 and 63 they are asking for the standard reaction enthalpy for the reactions and 59 uses kJ/mol while 63 only uses kJ. The questions are basically identical except for the reactions so how do we know when to use one or the other?
Sat Jan 13, 2018 5:58 pm
Forum: Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)
Topic: Sig Figs for Question 8.45 (a)
Replies: 5
Views: 192

### Re: Sig Figs for Question 8.45 (a)

I've heard that if the answer ends in .5, you would round to the nearest even number, which in this case would be 448. I am not sure if this is the official rule to go by but I remember reading it in 14A so maybe that would explain it.
Sat Jan 13, 2018 5:49 pm
Forum: Phase Changes & Related Calculations
Topic: Phase Changes
Replies: 13
Views: 507

### Re: Phase Changes

An easy way to think about this is that exothermic releases heat, meaning usually involving cooling, so the phase changes being exothermic would be from gas to liquid (condensation), liquid to solid (freezing), or gas to solid.
Fri Jan 12, 2018 2:39 pm
Forum: Phase Changes & Related Calculations
Topic: Heating Curve
Replies: 6
Views: 233

### Re: Heating Curve

Does the length of the sloped lines indicate anything? Or is it just based on the steepness?