Chemical reaction Definition and 131 Threads

I've been researching a lot of chemistry lately and one thing confused me, apparently some spontaneous reactions require activating energy? At least thats what i found on Google but would it be contradicting the spontaneous part? Like when i think of spontaneous reaction i think like...

The way I understand it is that we have an aqueous solution of something that produces hydroxide ions. If there are carbon dioxide gas molecules in the solution then from the book I am reading it seems that the following definitely happens 1) One hydroxide acts as a Lewis base (donates...

So i'm doing a project for school with the local firefighters and we have to help save time to rescue people from a fire. So i had an idea, What if we made a transportable device that could contain the chemicals and stuff to create a decomposition reaction. I wanted to test my theory that...

My attempt: Species fluid and solid phase balances for a tubular reactor in which there is a homogeneous first order reaction and a heterogeneous reaction on the external surface of non-porous catalyst coated along the reactor wall. Mole balance equation for the fluid phase The heterogeneous...

Hi For a personal project, has the energy level diagram of the below reaction been derived? Voltage Applied4B+2LiNO3+C ------------->B4C+2LiNO2+O2 Thanks,

Conversion: 9.65 kg = 9650 g Mass Al = 26.98 g/mol Molar Mass Al2O3 = (2 x 26.98) + ( 3 x 16.00) = 101.96 g/mol Mol Al2O3 = 9650 g / 101.96 g/mol = 94.65 mol Mol Al Required = 94.65 mol x 2 = 189.3 mol Mass 100% Al required = 189.3 mol x 26.98 g/mol = 5.107x103 g Mass 80% Al required =...

1a) Step 1: Balance the equation - S8 + O2 -> SO2 = S8 + 8O2 -> 8SO2 Conversion (t to g) 6.00 t = 6x10^6 g Molar mass SO2 = 23 + (2 x 16) = 64 g/mol 6x10^6 g / 64 g/mol = 9.375x10^4 mol SO2 reqired amount Sulphur = 9.375x10^4 mol / 8 mol = 1.172x10^4 mol S8 Molar mass S8 = (8 x 32)...

Hello, I mixed these today: H3PO4 NaOH Tetrahydrofuran CH₂)₄O Cyklohexanon C6H10O 2-Butanon C4H8O It started to generate smoke. Just wondering if this gas might have been dangerous to breath in? theories? experiences? Thanks Stan

Hi I am trying to safely setup an experiment to measure a chemical reaction with a spectral detector. I was wondering how to setup the experiment safely in front of the spectral detector? Do I have to perform some calculations based on the chemical reaction beforehand? Or what? This is an...

Hi all, Is this energy equation of any meaning if there is no chemical reaction $$\triangle G= RT ln \frac{C_1}{C_2}$$ in compartments with concentrations $$C_1 \ and \ C_2$$ Thanks.

As in the summary, my question is : has the actual yield of the above reaction being determined experimentally?Thanks.Adrian Tudini

Given a balanced chemical equation, can we predict using computer models the maximum power of the chemical reaction? Thanks.

What is the definition of rate ##(-r_a)=-\frac{dCa}{dt}## or ##(-r_a)=-1/V\frac{dNa}{dt}## ? I think the general one is the second one and first one is for constant volume reaction system. Is the above written rate equation only valid to batch reactor? If not can we use this in a PFR or MFR? In...

The question arises in which procedure to follow, a balance by element or by compound? The excersise is this: A mineral of a process contains contains 90% FeS2 and 10% inerts by weight. This materialit is calcined with 25% excess air, according to the reaction: FeS2 + 02 ► Fe203 + S02 The...

I’m a high school student, I generally get problem in chemical reactions. I understand all physical and chemical properties of a compound, for example carboxylic acid have all the acidic property and aldehydes are highly polar. But the problem comes in chemical reactions like shift of positive...

##dU = dw + dq ## vs ##dU = dw + dq + µdN## Which equation do we apply to a closed system involving chemical reaction? According to textbooks, the first equation holds for any closed system in the absence of fields and kinetic energy. However, later chapters use the second equation for...

Hi. Basically, the title. I've been thinking about combining phenolphthalein and bromothymol for this purpose. Will this work? Thoughts?

Homework Statement You may have noticed that water sometimes drips from the exhaust of a car as it is running. Is this evidence that there is at least a small amount of water originally present in the gasoline? Homework Equations not sure if there is one. The Attempt at a Solution...

I'm confused in the balancing of a reactor , let's say the inlet volumetric flow rate is ##v_○## and outlet volumetric flow rate is ##v_1## Doubts: 1) How is the volumetric flow rate and volume of the reactor ##V## are related to each other ? 2) If the volumetric flow rate is constant (...

If I have a chemical reaction in closed system, how can I evaluate the change in T and P? I have: - one equation for the chemical equilibrium - one equation for the energy balance but I need an other one! entropy balance, maybe? Thanks Ric

Hi! I've got this problem: 1,20 g of NaHSO4 is dissolved in water to 1,0 liters and pH=2,194. What is the acid dissociation constant for HSO-4? I assume I have to start with writing the balanced reaction, but I don't get how I do that. I know that I'm supposted to start with NaHSO4 + H2O , but...

Hi, I'm hoping to get clear on some chemical nomenclature. A "chemical reaction" is a process that involves some sort of chemical change. But a conformational change doesn't involve a chemical change, just a shape change, thus from what I understand, it cannot be termed a "chemical reaction"...

This is probably the weirdest chemical reaction you'll ever see.

Homework Statement In hydrogen atom ionization H→p+e show that ##μ_H=μ_p+μ_r## Homework Equations G=μN (N is the number of particles) The Attempt at a Solution (1) I think the question should say "Find chemical potential relation AT EQUILIBRIUM", don't you think? (2) My professor said that...

I'm currently doing a literature review on ultracold chemistry with an emphasis on collisional theory and quantum phenomena. I'm an undergraduate physics major, and I'd start my discussion of this topic by moving from basic Newtonian conservation laws and concepts like Coulomb repulsion to the...

Hello, this is my first posting on this forum. I enjoyed Chemistry in high school, though the arts were where my abilities drew me. I've learned that a ratio of 2 hydrogen to 1 oxygen, when ignited by a certain amount of heat, will create a small amount of water. I will give a brief outline on...

Homework Statement Toluene, C7H8, is burned with 30% excess air. A bad burner cause 15% of the carbon to form soot (pure C) deposited on the walls of the furnace, what is the Orsat analysis of the gases leaving the furnace?Homework Equations C7H8 + 9 O2 => 7 CO2 + 4 H2O 30% excess of air What...

Homework Statement The decomposition of phosphine 4PH3(g) + P4(g) + 6H2(g) is first-order with respect to phosphine with a rate constant k = 0.0155 s-l at 953 K. If the decomposition occurs in a constant-volume batch reactor at 953 K, calculate, for 40% conversion of PH3, (a) the time...

Not sure if this is well know but for some reason, I don't know if exactly same chemicals make chemical reactions with one another and if yes, how common that is?

Homework Statement Homework Equations The Attempt at a Solution 2(255) - [(1)(159) + (1)(243)] = +108KJ The answer key says its b) -108KJ. Am i doing something wrong or is the book wrong?

For organic chemistry we typically look at the stability of the end product to determine if the reaction will proceed. For instance for an Sn2 reaction we would check if the product anion is more stable or less stable than the nucleophile attacking - if the product anion is more stable than the...

One that occurs immediatly?

I was doing a science experiment involving enzymes and hydrogen peroxide, and by adding heat to the catalase, it should have sped up the reaction, but instead it slowed it down. Is there a reason why this happened?? Isn't heat supposed to speed up the reaction, instead of slowing it?

Only particles that possesses enough energy to overcome the activation energy and orientated correctly will collide and form products. How about those particles which do not possesses enough kinetic energy to overcome the activation barrier? Does it mean that for a particular chemical reaction...

Hi, My Modern Physics lecturer is of the opinion that the energy dissipated during exothermic reactions is due to infinitesimally small change in mass of the reactants. Similarly, he said that an infinitesimally small part of the food we eat gets converted into the energy using which we perform...

Homework Statement The entropy change of surrounding is greater than that of the system in a/an (A) exothermic process (B) endothermic process (C) both (A) and (B) are correct (D) none of these are correct Homework EquationsThe Attempt at a Solution ΔStot = ΔSsys + ΔSsurr For a spontaneous...

I have been reading about how NaOH (Sodium Hydroxide) reacting with HF (Hydrofluoric Acid) yields the products H20 (Water) and NaF (Sodium Fluoride). If I were to do this, would I need the EXACT same quantity of NaOH as HF to get H20 and NaF?

Hi guys I was wondering of someone on here could briefly enlighten me on the chemical reactions that would occur with a Teflon Coated high carbon steel hook and a lead sinker while underwater? I am looking into the signals that may or may not be given off by these items both separately and with...

Dear PF Forum, Do anybody know the 'Wolfram Alpha' for chemistry? For example. If I enter: HCl + NaOH The website will produce something like HCl + NaOH -> NaCl + H2O (+ or - energy would be preferable) or if I enter: C6H12O6 + O2 The website will produce something like: Do you mean: C6H12O6 +...

.. reaction. This may seem a nonsensicle question but I'll go ahead anyway. Say if I have a process that has an emission spectra dominated by excited state molecular emission, can I relate this in any way to the amount / number of chemical reactions occurring? Thanks for any help

Hello, "Reversible processes are at equilibrium : Driving force is only infinitesimally greater than the opposing force Process occurs in a series of infinitesimal steps, and at each step the system in at equilibrium with the surroundings It would take an infinite amount of time to carry out...

Homework Statement Problem 18B.13 from Transport Phenomena, BSL. Tarnishing of metal surfaces. In the oxidation of most metals the volume of oxide produced is greater than that of the metal consumed. This oxide thus tends to form a compact film, effectively insulating the oxygen and metal from...

Example, I have a mixture of 5 grams of oxygen and 10 grams of hydrogen. I ignite them. How much force will the explosion do? Yes, I did think about posting this in the chem category but this is about forces, right?

Homework Statement I am having trouble on knowing what products are formed in a chemical reaction, such as these : i) aluminium oxide and sodium hydroxide Al2o3 + 2NaOH + 3H2O -> NaAl(OH)4 How do we know that we have to add H2O? And how we know that the product is NaAl(OH)4 ? Why can't it be...

im reading a chemistry text and its says in daltons law chemicals can not change into atoms during a chemical reaction.but if fusion is a chemical reaction then this is wrong beacuse in stars for example hydrogen combine with hydrogen to form helium .i guest i need a little clarification of...

Hi, I have a very interesting but challenging question. Consider any chemical reaction that involves gas production (e.g. H2 gas is produced in KOH etching silicon). As we know, the produced gas will detach from the surface and reaction can continue. What if the gas doesn't detach from the...

Does anybody know where I could find worksheet to practice naming the state of matter in chemical reactions (with answers in the worksheet to check) as I have problems with that. Especially deciding when it is aqueous. I know (well at least i am right) that when you have acid as reactants it has...

Homework Statement A certain pyrite ore contains 85% of FeS2 and 15% of inerts. This ore is introduced into a roasting furnace with 20% excess air, in order to oxidize the FeS2 in the reaction: \textrm{FeS}_2 + \frac{11}{4}\textrm{O}_2 \rightarrow \frac{1}{2}\textrm{Fe}_2 \textrm{O}_3 +...

This is a very basic question. When I see a chemical formula, like for example combustion of methane: $CH_4+2O_2->CO_2+2H_20$ and I compute the standard enthalpy of reaction $H_r$, do I have always to think about this value $H$ and about the chemical reaction as describing a "certain amount"...

Homework Statement A simple and very violent chemical reaction is H + H -> H_2 + 5 eV (1eV = 1.6x10^-19 J, a healthy amount of energy on the atomic scale). However, when hydrogen atoms collide in free space they simply bounce apart! The reason is that it is impossible to satisfy the laws of...