CHEMISTRY COMMUNITY

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The rate of a reaction is proportional to the rate constant for the reaction. The Arrhenius equation relates the rate constant, k, for the reaction at each temperature, T, to the activation energy, Ea , where R is the universal gas constant (8.3145J⋅mol−1⋅K−1). k=Ae−EaRT Dividing the rate constant o...

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The rate of the overall reaction is governed by the rate of the slowest step in the mechanism. In this proposed mechanism, the slowest step is I(aq)+HClO(aq)→HIO(aq)+Cl−(aq). For an elementary step, its rate law can be written from its chemical equation. Therefore, the rate law for the slowest step,...

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When a molecule is deprotonated to become its conjugate base, it gains negative charge – and therefore becomes more electron-rich. And when a molecule is protonated to become its conjugate acid, it loses a unit of negative charge – and therefore becomes more electron – poor

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Hey! So this was my problem... The half‑cell reactions are Pb(s)+2Cl−↽−−⇀PbCl2(s)+2e−E∘=0.267 V 2AgCl(s)+2e−↽−−⇀2Ag(s)+2Cl−E∘=0.281 V Electrons move spontaneously from the half cell with the lower reduction potential to the half cell with the higher reduction potential. Therefore, Pb(s) is oxidized ...

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The one with the highest reduction potential will be what you want to select as the reduction half-reaction and therefore be your cathode. The one with the lowest reduction potential will be what you want to select as the oxidation-half reaction and therefore be your anode.

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First-order reactions are very common. We have already encountered two examples of first-order reactions: the hydrolysis of aspirin and the reaction of t-butyl bromide with water to give t-butanol. Another reaction that exhibits apparent first-order kinetics is the hydrolysis of the anticancer drug ...

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the chemical reaction rate is directly proportional to the concentration of reactants. This implies that the chemical reaction rate increases with the increase in concentration and decreases with the decrease in the concentration of reactants.

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For first-order reactions, the equation ln[A] = -kt + ln[A]0 is similar to that of a straight line (y = mx + c) with slope -k, which would just be a straight line.

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Hi there! I am not 100% sure if there are any specific equations that we would use for electrolysis, but I could be totally wrong. However, I did find this one, Q=I⋅t.

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The main difference between enthalpy and internal energy is that enthalpy is the heat absorbed or evolved during chemical reactions that occur in a system whereas internal energy is the sum of potential and kinetic energy in a system. Moreover, the internal energy of a system reduces when it works o...

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E cell means electrode potential of a cell. E0 cell means standard electrode potential means electrode potential measured at 1 atmosphere pressure, 1 molar solution at 25° C. E^o Cell is the cell potential at standard state, which doesn't change based on concentration (or any other reason, only havi...

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Initially, an increase in substrate concentration leads to an increase in the rate of an enzyme-catalyzed reaction. As the enzyme molecules become saturated with substrate, this increase in reaction rate levels off. The rate of an enzyme-catalyzed reaction increases with an increase in the concentra...

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I believe it would just be the increasing of the atomic number as well as the masses.

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Q can be used to determine which direction a reaction will shift to reach equilibrium. If K > Q, a reaction will proceed forward, converting reactants into products. If K < Q, the reaction will proceed in the reverse direction, converting products into reactants.

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The key difference between galvanic cell and concentration cell is that a galvanic cell may or may not have the two half cells with the same composition whereas a concentration cell has two half cells with the same composition. Both the galvanic cell and the concentration cell are electrochemical ce...

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Yes if everything went well and you were able to answer the questions then you should be fine!

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The equations relating ΔG∘ and K to E∘cell are ΔG∘=−RTln(K), ΔG∘=−nFE∘cell, E∘cell=−ΔG∘nF. When K=1, ΔG∘=−RTln(1)=0, Ecell=−0nF=0. Thus, when K=1, both E∘cell and ΔG∘ are equal to 0. For any value greater than 1, its logarithm is positive. For any value less than 1, its logarithm is negative. Based ...

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For like a strong acid, you can add the acid or base to water, thus depending what you get, high reactivity means a stronger acid or base.

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Strong acid is an acid that ionizes completely in aqueous solution. It always loses a proton (H+) when dissolved in water. Weak acid is an acid that ionizes partially in a solution. It gives off only a few of its (H+) atoms when dissolved in water. I hope this helps!

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Hey there! Hf is used for standard enthalpy of formation for all equations, but Hc denotes enthalpy of combustion. This value would be helpful for a Hess's law calculation that is typical of combustion reactions.

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Hey! Rate determining step is the slowest step within a chemical reaction. The slowest step determines the rate of chemical reaction. The slowest step of a chemical reaction can be determined by setting up a reaction mechanisms. Many reactions do not occur in a single reaction but they happen in mul...

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ΔH represents a change in that amount of energy, and would usually be represented by a change in temperature. ΔH = q only in certain circumstances. If there is work, then your enthalpy change does not equal your heat.

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Catalyst cannot change pre-exponential factor for a reaction, but the pre-exponential factor depends on frequency of collisions, it is related to collision theory and transition state theory. k=AeEa/RT. The Arrhenius equation introduces the relationships between rate and A, Ea, and T, where A is the...

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Hi! The full valence electron shells of these atoms make noble gases extremely stable and unlikely to form chemical bonds because they have little tendency to gain or lose electrons.

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There are two methods for distinguishing between exothermic and endothermic reactions. When energy is released in an exothermic reaction, the temperature of the reaction mixture increases. When energy is absorbed in an endothermic reaction, the temperature decreases. If ΔH is positive, the process a...

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Yes, I believe that is correct, but I did check my grade on BruinLearn for the community chemistry posts and it says 12/21 for me, even though I have up to 21 posts, so I am not sure if we can post up to March 18 and still get full credit.

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Hi! So online I found that reduction potentials of aqueous solutions are determined by measuring the potential difference between an inert sensing electrode in contact with the solution and a stable reference electrode connected to the solution by a salt bridge. However, I would not know if you coul...

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Hello, I am also having trouble with this question. I tried so many different ways but I still keep getting the wrong answer.

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Cathode rays are produced when there is a potential difference (voltage) applied across the electrodes. The electrons begin to emit from the cathode towards the anode and accelerate inside the gas due to this high potential difference.

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A catalyst is a substance that speeds up a chemical reaction, or lowers the temperature or pressure needed to start one, without itself being consumed during the reaction. Catalysis is the process of adding a catalyst to facilitate a reaction.

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could someone explain to me the concepts to refer to solve this question. ThanksScreen Shot 2023-03-05 at 9.44.52 PM.png It will also be the same for the second part as well To find a reagent that will oxidize Cu to Cu+ but not Cl− to Cl2, look for a reagent that is a better oxidizing agent than Cu...

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Hey so my question was a bit different I had Pb and Pb2 instead of Ag and Ag+, but this is basically the concept. To find a reagent that will oxidize Cr to Cr2+ but not Pb to Pb2+, identify a reagent that is a better oxidizing agent (electron acceptor) than Cr2+, but a worse oxidizing agent than Pb2...

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Hey! Thank you so much for sharing this! It is going to definitely help me since I have been struggling a lot!

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A redox equation can be balanced by dividing the equation into two half-reactions and then balancing each half-reaction for mass and charge and after you can equalize the number of electrons transferred in each half-reaction and add the half-reactions together.

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Hi! I am a bit confused about the 'order' of reactions, and I have a few questions. What does this order refer to? What are the differences between zero, first, and second order reactions in terms of the rate equation? How do you know what goes on the y and x axis for plotting them? Hi! To begin wi...

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Hello, I am having trouble figuring out the balance equation for the first part of this question. I have down 2MnO−4(aq)+3S2−(aq)+4H2O(l)⟶3S(s)+2MnO(s)+8OH−(aq) but I am pretty sure it isn't right and I am not sure what to do next.

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Hi, most of the time, you can look at the ion the element forms. Sometimes, you have to actually calculate it based on the compound. There are some elements like hydrogen that can either be +1 or -1, for example. Oxygen is typically -2, except when it is in O2 form, which is typically in peroxides....

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What would you guys recommend to do the night before the final??? I tend to have a hard time staying calm and stressing about the exams the day before.

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Caitlyn Nguyen 2A wrote:Hi, I was given different numbers for the #10 on my Achieve, but you might have miscalculated in one of your steps; I solved the equation you wrote and got 30.185 degrees Celsius. Hopefully this helps.

Hey! Thank you so much! I for sure miscalculated lol.

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I would definitely look into the textbook readings and problems posted on the syllabus more to help with the next midterm!!

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Alec Villarreal 2H wrote:Do you get notified if someone has responded to one of your posts?

There is also a notification bell located in the top right of the website and you can check there as well!

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Hi! I am having a bit of a struggle with this question. After solving for it, I got 31.1degrees C as my answer, but it keeps marking it wrong. I am not sure if I did something wrong in my calculation.

34.6g x 0.903(T2-64.9)= -50 x 4.184(T2-25)

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When you use q=mc(delta T), it is always in reference to the object that the heat is being measured for. A negative q would represent a loss of heat energy (such as an exothermic reaction) and a positive q means that heat energy is gained by the object. In the specific case of #11, there are 2 &quo...

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I was trying to find the individual enthalpy for M(s) on the list provided in Achieve, but I could not find it. Does anyone know how I can get it?

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I know that the step up sessions are very helpful as well as the videos on Lavelle's website!

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Danielle Paisley 1H wrote:Interesting article details how the sun converts plastic and CO2 into fuel. This is very promising for a sustainable future!
https://www.anthropocenemagazine.org/20 ... chemicals/

Great! Thank you so much!

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Hey guys! I opted out of inclusive access a couple of days ago and I was still able to use achieve even after opting out last week. With that said, I am afraid that starting this week, I might not able to access my achieve account to do homework. Does anyone know if I can still access achieve to do...

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juliannesue wrote:How do you reply to a specific comment/earlier reply? I clicked the quotation marks but I didn't know if that would create a new post entirely or lead to a new response.

I think it creates a new post entirely under the post you are replying to.

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juliannesue wrote:How do you reply to a specific comment/earlier reply? I clicked the quotation marks but I didn't know if that would create a new post entirely or lead to a new response.

I think by clicking the quotation marks, it allows you to reply under the comment that you would like.

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I was just able to do this by scrolling all the way to the top of the chemistry community website and next to the FAQ there is a link to register. However, this is my first time registering, so I am not sure where I can add my name yet.

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