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.
Simple rigid body collision reaction (Newton III)
Hi everyone! I'm writing a physics engine as part of a game I'm making. Up until this point I've implemented inter object collisions in a rather quick and dirty manner. Whenever something moves into something else, it is simply teleported back...
What reaction or series of reactions can I react SO2 gas with that will strip off the O2 and leave me with elemental S?
It seems most reactions will just make a sulphates etc.
Homework Statement
say we were hydrating Cobalt chloride crystals
why would
(i) more cobalt chloride
(iii) less water
result in a GREATER temperature change of reaction>
thanks
Homework Equations
The Attempt at a Solution
for ii I have used Q = mcΔt and on re-arranging to...
reaction of alkaline Earth metals with O2
i just got in my textbook that Ba,Ca,Sr is kept in paraffin but Mg and Be are not as they form a protective coat of oxide on their surface.i don't get a clue about this .could anyone explain me this?
So, in my thermo book, it says that the gibbs free energy change of a reaction is the free energy received by the system at constant T,p and constant chemical potential when the extent of the reaction varies by one mol. The part that is confusing me is the "constant chemical...
Homework Statement
Part A:
Mass of Mg (s) = 0.31 g
Initial temperature of calorimeter contents = 24.1 C
Finial temperature of calorimeter contents = 36.8 C
Part B:
Mass of MgO (S) = 1.22 g
Initial temperature of calorimeter contents = 24.0 C
Finial temperature of calorimeter contents = 31. 9 C...
Homework Statement
C3H5(NO3)3 --> N2 + CO2 + H2O + O2
Homework Equations
non O and H oxi states as follows
C: -2/3 to +4
N: +5 to 0
The Attempt at a Solution
Oxi: C3H5(NO3)3 --> CO2 +6e- added 6 electrons to balance net carbon oxi state
Red: C3H5(NO3)3 +15e- --> N2 added 15...
Good evening, everyone :) i m mathsTKK, new member od physics forum, nice to know everyone in this forum ;)
I have a question regarding chemical software which can help me a lot. I am currently using Accelyrs 3.1 to do some research, but I meet some difficulties in fully using it as some of...
Homework Statement
At 25 C a catalyzed solution of formic acid produces 44.6 ml of carbon monoxide gas in 30s.
a) Calculate the rate of reaction with respect to CO(g) production.
Homework Equations
Rate = dC / dT
The Attempt at a Solution
dC should be expressed in mol/L but I...
Can someone please help me answer this question and explain the concepts/solution step by step:
Prof. W.H Bogus claims that he has prepared a powerful new catalyst that makes it possible to synthesize NH3 with a 70% yield in a reactor operating 500K and 2 atm pressure and having a feed...
Homework Statement
Calculate the total kinetic energy of the products of the reaction d+C-13 --> N-14 + n if the incoming deuteron (d) has 36.3 MeV.
Homework Equations
Q=(Parent Mass - Daughter Mass - Decay Particle Mass)*c^2
1u = 931.5 MeV
C-13 = 13.00335u
N-14 = 14.003241u
Neutron...
I am working on a project that needs 2 chemicals to react and change colors. The catch is they most likely need to be or come in a powder form, non toxic, and relatively inexpensive.
PLEASE HELP!
Today in class my chem teacher was insistent that 2Mg + O2 = 2MgO was a synthesis reaction. this I agree with. however, he was also adamant that this was not a combustion reaction, when it our textbook it specifically gave us this very same example as a type of combustion reaction. Question: is...
Homework Statement
2HCl + Na2S2O3 -> 2NaCl +S + SO2 + H2O
Find the order of reaction with respect to S2O32- and H+
volume of 3.0M HCl was held constant at 2ml
Homework Equations
S2O32- + 2H+ -> S + SO2 + H2O
rate = k[Na2S2O3]m[HCl]n (see number 3.)
The Attempt at a Solution
i just...
Homework Statement
When Fe(NO3)3 and KSCN reated, it immediatly turned red. my teacher says this si the stuff they use for fake blood in movies. My problem is, we must state the reaction type. Homework Equations
the products, I am assuming, are FeSCN and KNO3 (i know I did not yet balance...
Does anyone know the experiment where distinct circular patterns appear to emerge in a liquid chemical reaction? This experiment was covered in my thermodynamics class due to its relevance of order emerging from chaos. All I remember about the experiment is that it was not believed at first for...
I accidentally threw dettol (chloroxylenol) down a clogged toilet drain without knowing there was already sodium hypochlorite there. For some strange reason, after flushing down once, it became even more clogged and it's still all lying there. I closed the door in fear of inhaling toxic fumes. I...
I'm in a first year organic chemistry class with a biochem focus and I am going to do a project on ketoacidosis. While I can find the pathway online, since this is an organic chemistry class, I figure that a reaction mechanism that illustrates electron movement (arrows and such) would be...
Just as the title says, I'm having difficulty understanding why the concentration of inert gas is not included in the reaction rate. I would think adding a higher concentration of N2 (or some other inert gas) would increase the reaction rate. Perhaps, I'm confusing reaction rate with space time?
Homework Statement
For the reaction N2(g) + 3H2(g) <---> 2NH3(g)
I am supposed to determine the equilibrium constant at 298K and 1 bar. We have been given a table that states that
for NH3(g):
\Delta_{r}G^{\Theta}= -16.45 kJ/mol
I know that
\Delta_{r}G^{\Theta}= \Sigma v...
http://en.wikipedia.org/wiki/Standard_enthalpy_of_reaction" of reactants (ΔHfO).
My question is, why?
And I also know that I can find http://en.wikipedia.org/wiki/Standard_enthalpy_of_reaction" (ΔHrO) by subtracting the bond energies of the reactants from the products. The result differs...
My friend said that two horses pull the Magdeburg hemispheres with same force is as same as a horse pulls the Magdeburg hemispheres which is tell on a tree(I may forget the details about the assumption)
Why?
Another Q. about action and reaction
i don't know why the reading isn't 2Mg,but is...
The purpose of this chemistry lab was to prepare/synthesize Bis(2,4-pentanedionato) Copper (II), which is also known as Cu(C5H7O2)2
I was given the following format for a chemical equation in a lab that needs to be balanced:
Cu2+ (aq) + 2 base-n (aq) + 2 C5H8O2 (aq) → Cu(C5H7O2)2 (s) + 2...
Homework Statement
I want to find a relationship between the number of moles of O2 used and the number of CH2 units in an alkane in a complete combustion reaction.
Homework Equations
The Attempt at a Solution
Right now I have come up with a math equation, given X units of CH2...
Okay, so we did a lab in class with Na2CO3 in BaCl2 first. The reaction formed a white precipitate, and I suppose the products are BaCO3 + 2NaCl. Not sure if NaCl is dissolved or not, or if it was the white precipitate I saw, but anyways, here's my question...
We added HNO3 to that new...
The standard potential of the Cl−(aq.)|AgCl(s)|Ag(s) electrode in the vicinity of T = 298 K has been found to fit the expression
E\theta/V = -0.00558 + 2.6967x10^-3(T/K) - 8.2299x10^-6(T/K)^2 + 5.869x10^-9(T/K)^3
Find the standard Gibbs free energy, the standard enthalpy, and the standard...
Critical mass is over 50kg so let's say I have 2 halves of a sphere of the isotope U-235, each weighing 30 kg. I drop one onto the other so that they form a supercritical sphere. No doubt a chain reaction would begin, but I assume it would produce energy on the level of a nuclear reactor rather...
Homework Statement
Calculate the heat of reaction per mole of water formed in the acid-base reaction. Assume that the total mass of the solution is 150g.
75mL of 2.0M NaOH added to 75mL of 2.0M HCl in a styrofoam cup. Average initial temp = 295.65K. final temp = 308.8K
Homework...
Hi guys,
I'm facing a problem.
I've read a paper where they tried to synthesise a crystal and they give the following reaction mixture molar composition:
3.0 SiO2
1.0 Al2O3
0.1 NaCl
276 H2O
What does it means?
It can't be the molar fraction since the sum of all the fraction must give 1 as...
um, i placed my elbow on the table, and i think i mustve hit some ideal spot that actually caused a (static?) reaction up my lower arm.
what i want to know is, what exactly it is, why did it happen, and why it only happens sometimes?
PER - chemical reaction
Q: A reactor is needed to convert A to R in a liquid reaction. The stoichiomentry is simply A→R and the rate data is given in the table below (P5.21, Levenspiel 1999).
For the reactant concentration to drop from CA0 = 1.3 mol/L to CAf =0.3 mol/L, determine,
a)...
Is this nuclear reaction exothermic or endothermic??
Homework Statement
Is this nuclear reaction exothermic or endothermic??
alpha particle + beryllium -> carbon12 + neutron
Homework Equations
The Attempt at a Solution
Im not quiet sure which one it is, I don't know what...
Well this is something that has been aggravating me since I did the experiment at school and really just want to solve and not have it happen again.
My problem is while mixing varying mL of NaOH and HCl we (my group and me) were supposed to record the varying changes in temperature for the...
Homework Statement
http://www.mrev.org.uk/A-Level_Site/New%20A-Level%20Unit%204/Rates.html
(the answers are at the top - see link)
Could someone please help me with the question (about half way through) on ethyl ethanoate and sodium hydroxide.
in cii) we identified the half life doubles...
I am supposed to balance the following reaction:
CdS + HNO3 (dil) → Cd(NO3)2 + NO + S + H2O
After writing out all the oxidation numbers for each atom, I found that Cd and N are both reduced (Cd5+ → Cd 1+ and N5+ → N2+).
I am wondering how to approach this problem. Is it possible to have 2...
Homework Statement
Take for example the problem given below:
C + O2 → CO2 ΔH°f = -393.5 kJ/mol
2CO + O2 → 2CO2 ΔH°rxn = -566.0 kJ/mol
To determine the ΔH°f of CO from the reaction of C graphite and O2 given those equations, one would solve it as: -393.5 kJ/mol + 1/2(566.0)=...
tert-butyl bromide reacts with HOH to give HBr and the corresponding alcohol ,
C
C-C-C
OH
But tert-butyl alcohol reacts with HCl to give tert-butyl chloride.
HBr is a "stronger" acid than HCl. Is this part of the explanation of the different reactions?
Homework Statement
What is the equation for the reaction of a alpha particle and beryllium with production of one neutron
Homework Equations
Use an a chem equation
The Attempt at a Solution
The masses are 4 + 9 = 1 + x, so x = 12. The atomic numbers (protons) are 2 + 4 = 0 + x...
I was given 2Na + 2H2O → 2NaOH + H2
My only question here is whether the Na on the reactants side is 0 because it is alone? And is it the same thing for the H2 that is alone on the products side?
So if were the case Na would oxidize and H would reduce?
Homework Statement
The concentration of the reactant A has been studied as a function of time. By a suitable plot of the data below, show that the reaction is first order, and determine the rate constant, k, and the half-life, t1/2. Use the integrated rate equation to determine [A] when t =...
What exactly is a double displacement reaction? I searched my textbook for the term--yes, I did check the glossary first--and it proved futile. My teacher alludes to this term and even has one power point slide to it. It says, "When an aqueous solution of sodium carbonate is added to an aqueous...
Please teach me this:
What prevent the reaction changing leptons to hadrons and vice versa?.Because both leptons and hadrons are ruled by electro-weak interaction,so why the reaction can not happen?
Thank you very much in advance.
1. It has been found by experiment that the molar mass of the Rn nucleotide is 221.9703 g and that of the Po nucleotide is 217.9630 g. The molar mass of helium is 4.00150 g. Given this information, and the information from the class, calculate the energy evolved, in kJ, for the following nuclear...
Homework Statement
For each reaction, give balanced chemical equations or NR (no reaction) and rationalize your answers in terms of trends in oxidation states. Calculate net potential for the reactions:
a) Fe2+(aq) + Co3+ (aq) (acidic conditions) →b) CrO42−(aq) + MoO2(s) + H+ (acidic...
is it possible to have a triple replacement type reaction? I know of single and double replacement but what if you mix sodium carbonate, magnesium hydroxide, and potassium sulfate all together (this is all made up just for an example).
would all the different ions mix to form all possible...
I thought I understood it cause I always had the right answer ever since I learned about it.
But now my friend asked me a question about why does a piece of chalk break if you put a heavy thing on it, say a car.
If we just think about action and reaction, the forces have to be along a...
Homework Statement
Topic
Homework Equations
http://en.wikipedia.org/wiki/Horner%E2%80%93Wadsworth%E2%80%93Emmons_reaction
This is basically a variation of a wittig reaction.
The Attempt at a Solution
I'm trying to understand this concept, because the chemistry gods have decided that it...
Homework Statement
See attachment there is reaction.why --OH attach to 2nd carbon. why not it attach first carbon(from left).
Homework Equations
steric hindrance
The Attempt at a Solution
there seems greater steric hindrance in right carbon(2nd from left) than left one.