A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.
The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Reactions often consist of a sequence of individual sub-steps, the so-called elementary reactions, and the information on the precise course of action is part of the reaction mechanism. Chemical reactions are described with chemical equations, which symbolically present the starting materials, end products, and sometimes intermediate products and reaction conditions.
Chemical reactions happen at a characteristic reaction rate at a given temperature and chemical concentration. Typically, reaction rates increase with increasing temperature because there is more thermal energy available to reach the activation energy necessary for breaking bonds between atoms.
Reactions may proceed in the forward or reverse direction until they go to completion or reach equilibrium. Reactions that proceed in the forward direction to approach equilibrium are often described as spontaneous, requiring no input of free energy to go forward. Non-spontaneous reactions require input of free energy to go forward (examples include charging a battery by applying an external electrical power source, or photosynthesis driven by absorption of electromagnetic radiation in the form of sunlight).
A reaction may be classified as redox in which oxidation and reduction occur or nonredox in which there is no oxidation and reduction occurring. Most simple redox reactions may be classified as combination, decomposition, or single displacement reactions.
Different chemical reactions are used during chemical synthesis in order to obtain a desired product. In biochemistry, a consecutive series of chemical reactions (where the product of one reaction is the reactant of the next reaction) form metabolic pathways. These reactions are often catalyzed by protein enzymes. Enzymes increase the rates of biochemical reactions, so that metabolic syntheses and decompositions impossible under ordinary conditions can occur at the temperatures and concentrations present within a cell.
The general concept of a chemical reaction has been extended to reactions between entities smaller than atoms, including nuclear reactions, radioactive decays, and reactions between elementary particles, as described by quantum field theory.
hey guys
i am wondering what the difference between using Fe2O3 or FeO would be in a thermite reaction to produce aluminium oxide.
wouldn't the FeO produce a more energy since its enthalpy of formation is lower?
thanks for your answers!
Homework Statement
Is the following reaction possible? If so, by what force? Draw (one of, if applicable)the lowest order Feynman diagrams for the process.
n + n-bar --> ∏+ + ∏- + ∏0Homework Equations
N/AThe Attempt at a Solution
This process, it seems to me, should be possible. It...
Complcated Chemistry Reaction - impossible??
Help :(
My notes say:
Step 1 is a 221 reaction. If peroxides are used in your version, then the anti-Markovnikov bromide is formed. If your version had only HBr, the the Markovnikov bromide is formeed.
Step 2 creates organolithium or Grignard...
I am trying to determine the change of heat for:
N2H4(g) -> N2(g) + 2H2(g)
Here is what I did and what I got the correct answer is -86.0 which I am clearly not getting
[(163)+ (2*436)] - [(4*391) + (163)] = -692
thanks for any help!
Homework Statement
A meter stick is held vertically above your hand, with the lower end between your thumb and first finger. On seeing the meter stick released, you grab it with these two fingers. You can calculate your reaction time from the distance the meter stick falls, read directly from...
For we to obtain metallic magnesium from sea water we can precipitate it in the form of magnesium hydroxide if we add calcium hydroxide:
Mg2+ + Ca(OH)2 → Mg(OH)2 + Ca2+
Why does this reaction happen?
Basically, when a natural frequency acts on coke bottle, It resonates. During the resonance, the lump of air in neck of it goes under simple harmonic motion. It goes in and out the bottle, increasing and decreasing pressure of cavity of coke periodically.
When air goes inside the bottle, the...
Homework Statement
I understand how metallic oxide dissolve in water to produce OH- ion due to high electronegativity of oxygen. But I am having trouble understanding how non-metallic oxide dissolve in water to form acid?
For Homework I have to explain the reaction of Sulfur trioxide in water...
I read that matter-antimatter annihilation is not as useful as we thought because a large amount of energy is carried away by neutrinos. So, how much is this energy ? What is the percentage of the lost energy to the energy calculated from E=mc^2 ?
Homework Statement
https://dl.dropbox.com/u/63664351/Physics/MECH1.PNG
Homework Equations
Sum of Forces and Torque = 0
The Attempt at a Solution
I found similar problem here: http://farside.ph.utexas.edu/teaching/301/lectures/node133.html
Why is there no vertical reaction on a...
In "Future? Tense!" in his essay collection From Earth to Heaven (1965), Isaac Asimov wrote about the nature of science fiction. He noted that science-fictioneers are stereotyped either as indulgers in weird fantasies or as farsighted predictors of the future. After discussing some SFers'...
According to Newton 3rd law, every action will have a reaction. but how about buoyant force? if the buoyant force is the force of water on object then the reaction force will be the force of object on water. but is it other name for this force?
thanks for reply.
I'm only in a high school class. I just made up this problem to see if I'm getting the right idea in the long run. That, and then there's the fact that differential equations are SO MUCH FUN! :biggrin:
Homework Statement
Molecular bromine (initial concentration: 0.49 M) and formic acid (initial...
I think enthalpy of reaction is the amount of energy released when that reaction takes place (correct me if I'm wrong), but enthalpy of reaction is often written as per mole of something. As in kJ released per mol. What does the per mol represent? There are probably many reactants and products...
Homework Statement
I had an assignment where I needed to calculate reaction rate constants at different temperatures. I was supposed to use ab initio method (meaning I should use Spartan software), molecular partition functions and Eyring equation. The reaction was:
H+HD...
Homework Statement
The problem given was to find out the resulting compound of this Wurtz reaction process using dry ether (Na).
Homework Equations
Now the main problem I faced was how to remove the Cl-atom and Br-atom. I am new to this so please help me out.
The Attempt at a...
Homework Statement
From 9th edition of Raymond Chang's Chemistry (Problem 4.108):
"When 2.50 g of zinc strip were placed in a AgNO3 solution, silver metal formed on the surface of the strip. After some time had passed, the strip was removed from the solution, dried, and weighed. If the mass of...
Homework Statement
Find the substitution products of ( 2S, 3S)-2-chloro-3-methylpentane + CH3O- in SN2 reaction.
The Attempt at a Solution
Will the anti-attack of the nucleophile result in the change of S to R for both the chiral carbons or just for the one with Cl connected...
Hi everyone!
I'll say it from the start that I'm not knowledgeable with chemistry but I'll call for anyone's help in making me understand this simple reaction.
I'm interested in finding out what reactions are occurring when CO2 is dissolved in water. The scope is for my hobby which is...
How much mass is lost in a single D + T= 4He fusion reaction? And is all of the mass lost converted to energy or just some? The mass lost can be converted to energy using e=mc2.
Homework Statement
determine the change in enthalpy for the following reaction from the enthalpies of formation for the reactants and products. (C6H5OH -165 kJ/mol, CO2 -393.15 kJ/mol, H2O -285.83 kJ/mol)
Homework Equations
The Attempt at a Solution
No idea, been a while since I...
the equation from my textbook: 2k+2H2O yields 2KOH+H2 why? I thought that such reactions are when one element swaps with another but in this case, there is an extra H2
Homework Statement
(see attachment)
Homework Equations
The Attempt at a Solution
It looks to me a type of Claisen condensation but i did not realize it until i checked my book.
Before checking the book, i tried to do it by thinking on what is given in the question. We have a...
The reaction I did for the lab is:
H2SO4 + Mg --> MgSO4 + H2
In my graph, there displays the two variables - the concentration of sulfuric acid and the average rate of reaction in direct proportion. How do I explain the trend?
I know I can explain this qualitatively using collision...
I know that first we have to add H2 and a Lindlar catalyst in order to produce what is the reactant.
I thought adding O3 would be an ozonolysis reaction.
An ozonolysis reaction should yield this:
I don't know why they added the Zn and CH3CO2H, though.
What does this even do in the...
Okay, I am trying to determine the product of hept-2-yne with HBr.
It looks like:
CH3CH2CH2CH2C≡CCH3 + HBr
I thought this thing would follow Markovnikov's rule, making the Br attach to the most substituted carbon and the H attach to the least substituted carbon...
I thought the...
Homework Statement
I'm just having a little difficulty understanding this E2 reaction.
The Attempt at a Solution
Okay, so I know that this is a one step reaction. Br is the base, but does water (the solvent) have effect on the reaction? I just assumed the Bromide would attack the H in...
1. Complete and balance the following equations, and identify the oxidizing and reducing agents:
2. Rules.
1) an element that is reduced Gains electrons and loses Oxygen
2) an element that is oxidized loses electrons but gains Oxygen
3. My attempt
Oxidizing Agent: 5e + 8H + MnO4 ^(1-) --->...
Abstract
The proposing Method unlike to using now others comprises in usage for plasma creation
and its further ignition the created in-situ halo-layer of high-energetic particles to the
puffed gas.
For realization of Method the following procedures should be performed consistently and...
Homework Statement
Complete the following reactions, giving the correct structure for each organic product:
eugenol + FeCl_3 ->
eugenol acetate + FeCl_3 ->
Homework Equations
The Attempt at a Solution
When I did this lab, my partner and I didn't notice a reaction when we...
Homework Statement
609.5 grams of vanadium (II) oxide, VO, and 832 grams of iron(III) oxide, Fe2O3, react according to the equation, which substance(s) and how many grams of each would be in the tube after the reaction completes? 3 points
Homework Equations
Equation:
2 VO + 3 Fe2O3 -> 6 FeO...
Homework Statement
(see attachment)
Homework Equations
The Attempt at a Solution
I am clueless here. I can conserve angular momentum but how will i find the "impulsive reaction"?
I read online that when you add a precipitating agent to a solution it initially becomes superstaurated and you have to take measures to decrease this supersaturation.
My question is why does it become supersaturated. Really having a hard time understanding this concept.
Homework Statement
This is my equation. I needed to balance it in an acidic solution.
H2O2(aq)---->H2O(l)
Homework Equations
I know that you should balance oxygen using H2O & hydrogen using H+.
I am confused on how you balance the ionic charges.
The Attempt at a Solution...
Hi
I'm new to the forum, so first I want to say hello to everyone.
I have been interested in Colloidal Silver lately, and I have produced it with electrolysis in distilled water with NaCl as an electrolyte. I have used a Silver electrode and cathode for both of these experiments.
I...
Homework Statement
Hi
Lets say I heat 50g of water to 80°C. I take another 50g of room temperature water and put it in a bowl.
Then I add this 50g of heat water to the bowl, the temperature in the bowl goes from 25°C to 48°C.
What is the amount of heat absorbed by the room temperature...
Homework Statement
The bromination of acetone is catalyzed by acid.
CH3COCH3 + Br2 + H2O ------> CH3COCH2 + Br- + H3O+
The rate disappearance of bromine was measured for several different initial concentration of acetone, bromine and hydronium ion as represented in the following table...
Hi there, I would like to know that if we have an leaning object supported by another object, both are supported by ground floor to satisfy static equilibrium condition, does the reaction force at the contact point produce cancelling torque (for the leaning object)? In general, can a reaction...
We did an experiment in class today with Barium and sulfate.
To one of the experiments we added a couple of drops of HNO3 to make it acidic and to the other one NaOH to make it alkaline.
the barium and then sulfate
The only one where they both reacted to make a precipitate were the acidic...
Hi, in nuclear reactors the water is heated while traveling through the core , now this heat comes from the nuclear reaction taking place in the core fuel assemblies, the part that I wnat to know is which of the elementary particles that come out of that reaction heat the water more and which...
1. Will the recorded temperature change for an exothermic reaction performed in a glass calorimeter be greater or less than that in a styrofoam coffee cup calorimeter? Assume glass to be a better conductor of heat than styrofoam.
Please explain
I'm supposed to find out the temperature of a reaction at equilibrium. I've calculated K=0.187, ΔS0=940J, and I know that ΔG0=1134kJ and ΔH0=1414kJ.
I'm supposed to use the R*T*ln(K)=ΔG0 formula, but my only problem is that ΔG0 is given for standard conditions,, ie where the temperature equals...
I can balance this equation using the half reaction method, but I want to learn to use the oxidation number method with this particular question to "broaden my abilities".
Homework Statement
ICl → Cl- + IO3 + I2
The Attempt at a Solution
I: +1 → +6: lost 5e-
I: +1 → 0: gained 1e-
(I'm...
Homework Statement
Find the total ionic (balanced) equation of the reaction of calcium hydroxide and phosphoric acid in aqueous solution.
Homework Equations
Solubility rules
The Attempt at a Solution
First, I balanced the reaction.
3Ca(OH)2 + 2H3PO4 --> Ca3(PO4)2 + 6H2O
The...
Homework Statement
The reaction between zinc and hydrochloric acid is carried out as a source of hydrogen gas in the laboratory:
Zn(s)+2 HCl(aq)\rightarrow ZnCl_2(aq)+H_2(g)
If 325 mL of hydrogen gas is collected over water at 25°C at a total pressure of 748 mm Hg, how many grams of Zn...
Hi everyone, I was just wondering how I would choose which species in an electrolytic cell to use as the cathode and which to use as the anode.
For example, for aqueous aluminum chloride (inert electrodes), H2O (-0.83V) and H2O (+1.23V) will be used as the anode and cathode for the half...
Homework Statement
Barium hydroxide is soluble in water. What are the spectator ions in the reaction of a dilute solution of barium hydroxide with hydro-sulfuric acid?
Homework Equations
The Attempt at a Solution
The chemical equation is:
Ba(OH)_{2(aq)}+H_{2}SO_{4(aq)}...
Homework Statement
Two balls, one soaked in concentrated HCl and the other in NH4OH are placed at the left and right ends of a 1m long evacuated glass tube, respectively. HCl and ammonia vaporize and travel down the tube, reacting to form a white ring where they meet. Where does the ring form...
Homework Statement
For the frame shown (see attached picture) , work out the horizontal reaction at B (ie find Bx)Homework Equations
EQUILIBRIUM EQUATIONS:
sum of moment = 0 (CCW is positive)
sum of vertical forces = 0 (up is positive)
sum of horizontal forces...