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.
Homework Statement
The elementary liquid phase reaction
A + B \rightarrow C
is carried out in a 500 L reactor. The entering concentrations of streams A and B are both 2 M and the specific reaction rate is 0.01 L/(mol min).
(a) Calculate the time to reach 90% conversion if the reactor is a...
Homework Statement
Write the balanced chemical reactions in ionic and neutral forms for:
i) Enargite leaching by sodium bisulfide in basic solution to form chalcocite and thioarsenate.
ii) Oxygen pressure oxidation of As2S5 in acid solution to form scorodite. Assume all sulfide sulfur forms...
Dear all
I have 250g of Copper 250g of Tin and 250g of Sulfur.
Everything is in powdered form.
Heated up in closed container wit surrounding nitrogen flow to avoid contact with Oxygen.
Heating ramp is 3 hours to 1000K.
What reaction will be the leading reaction?
How to calculate how fast will...
Homework Statement
This was a lab. I started with Maleic Acid. We performed a temporary corbonication to see whether or not the single bond would rotate to create fumeric acid, maleic acid or both.
The question that I have to answer that I cannot answer is: Explain the mechanism of the...
Homework Statement
Net ionic equation for sodium bromide and chlorine water with mineral oil
2. None
3. The Attempt at a Solution
Br-aq + Cl-aq → Br-aq + Cl-aq
or
Br-aq + Cl2aq → Br2aq + Cl-aq
Not sure if a halogen in water is an ion or not and can't seem to find good information online...
Hello,
I am working through some reaction engineering problems, and something in particular has caught my attention related more to chemistry I think than reaction engineering.
Suppose we have a gas phase reaction
## A + 3B \rightarrow 2C ##
If this is an elementary reaction, the rate law is...
So the question is: When 2.00 mol of SO2 reacts completely with 02 in a constant pressure reactor, the only material left in the reactor once the reaction has stopped is SO3 at 25 degrees celsius. The constant pressure in the reactor was 101kPa and 198 kJ of energy is released as heat. Assume...
Silly question lol
But Is there any reaction if calcium ion added to calcium hydroxide?
If NaOH or any alkali is added to metal ions, insoluble metal hydroxide is formed.
So, what if weak alkali Calcium hydroxide is added to Calcium ion, what will it happen? Will it has no reaction just like...
Homework Statement
in my book, it states that the reactivity of haloalkane in ascending order is C6H5CH(CL)CH3 <CH3)3 CCL <C6H5(CH3)2 CL ...
this involve formation of carbocation as intermediate , so i the lesser the partial negative charge on C atom during formation of carbocation ,the more...
Homework Statement
Hi. I have convert the following equation (which is in ionic form) into neutral form:
4S2O32-+O2+2H2O=2S4O62-+4OH-
The question tells me to use calcium as a counterion for all anions.
Homework Equations
N/A
The Attempt at a Solution
I basically just added calcium to the...
Greetings
While on an elk hunting trip in the mountains we awoke to roughly 2 feet of snow. Everyone wanted coffee and nobody had brought any conventional coffee tools. A cowboy boiled water in an aluminum pot just dumped coffee grounds in the water. Naturally a lot of those grounds floated...
This may seem like a really basic question (I'm teaching lower school science, and it's not my specialism!), but:
What causes the force which balances gravity, which I think is called "ground reaction force?"
All the descriptions I've seen say that the ground "pushes" up on a stationary...
Hi. I have a lab that concerns this reaction as follows:
S2O8 2- + 2e- = 2SO4 2-
Can anyone give me a hint as to why this reaction would NOT (and indeed does not as found in the lab) have a potential of ~ 2V from the H+/H2 reference? What is preventing the reaction from reaching its maximum...
Okay, so that is the master.chem problem that I am struggling with.
I feel I understand what's going on... Nickle is the anode that should be losing two electrons. What am I doing wrong according to mastering chemistry?
I feel this is an issue with how I am writing things? Or am I missing the...
Since D-D fusion releases H-3 + p and He-3 + n, how does the reaction He-3(n,p)H-3 occurring affect measurement of fusion rate by neutron count?
In other words, do I have to take He-3 absorbing neutrons into account while calculating the fusion rate or in what conditions can I neglect it...
Hello,
I am looking at reactions that change volume during the reaction, for example ammonia synthesis
N_{2} + 3H_{2} \rightleftharpoons 2NH_{3}
where it is clear that the products are less moles than the reactants. However, I am thinking of a scenario in a plug flow reactor where this is...
Homework Statement
So we know Enthalpy under constant Pressure and Internal Energy under Constant Volume. By
H = U + dPdV
U= I + W
W= -PdV
under Isobaric conditions
H = I -PdV + dPdV
= U
Enthalpy = Internal Energy
_________________________________________
Under Isochoric Conditions
W= O...
Hi,
I am a little confused with the concept of action reaction pair of forces. Does this depend on mass?
For example, if a train engine is pulling a buggy with force F, what would be the force applied by the buggy on the engine? The masses of the two are different and there is force of...
I have a simple question let's say object hits the wall at angle and reflect. Will reaction force from that impact exerted on wall be red line or green line ? ( I would like explanation why in each case)
Hello,
In class, my professor said that in a CSTR, the reaction rate is constant throughout a well mixed CSTR. He said in most cases, a PFR will react faster than a CSTR.
I can see how the PFR will have a fast reaction rate at the entrance to the tube, and slowest at the exit. However, what...
I want to ask the rate of reaction of organic compound is slower or higher than that of inorganic compound??
I have found an ansswer like that :
The organic paricles are molecules.
Because of strong covalent bonding within the molecule, organic compounds do not readily react. Reactions...
While rubbing the plastic rod with the wool causes the building up of charges on both of them.
1. What chemical reaction takes place between them.
2. Does it create anions and cations?
3. Is it the transfer of free electrons (I don't think so, because generally they are bad conductor of...
Homework Statement
While rubbing the plastic rod with the wool causes the building up of charges on both of them.
What chemical reaction takes place between them.
Does it create anions and cations?
Does it create free electrons (I don't think so, because generally they are bad...
Hello,
I am wondering, why is it that
##\frac {d[C]}{dt} \ne k[C]## in general, where ##C## is a chemical species, and the product ##k[C]## is the reaction rate, ##r##. ##r_{c} = k[C]##
My thoughts is that because the units aren't necessarily the same, therefore they can't be the same. But I...
Hello everyone, I was recently creating two different types of plasma for a Science Fair, one created from ionised Helium, (although it's the party balloon stuff, and I hear there's some Oxygen in them) and the other was created from air. I was testing how the plasmas reacted to magnetic fields...
tert-butyl bromide + MeOK in MeOH ----->
I would think that MeOK would dissociate in solution making it MeO- which would be strong enough to yank a proton off tert-butyl bromide and initiate an E2 reaction. Where am I going wrong?
PS - I am a tutor who hasn't done organic chemistry for a...
Please look at the image. For (b) and (c), what the solution manual says makes no sense to me.
You're reacting a primary alkyl halide with an unhindered base EtONa. They say that the only product is the alkene. Why do they not consider the SN2 reaction that WILL take place in larger quantity...
Homework Statement
Peroxydisulfate ion reacts with the iodide anion according to reaction 1:
S2O82- + 3 I-⇔ 2 SO42- + I3-
The amount of I3- formed can be determined by adding a known amount of SsO32- and allowing it to react according to reaction 2:
2 S2O32- + I3- ⇔ S4O62- + 3I-...
Homework Statement
The rate of a reaction at 100˚C is four times the rate at
50˚C. What is its activation energy?
(A) 1152 kJ. mol-1
(B) 80.1 kJ. mol-1
(C) 54.0 kJ. mol-1
(D) 27.8 kJ. mol-1
Homework Equations
k=e-Ea/RT
The Attempt at a Solution
I plugged in the activation...
Homework Statement
For the nuclear reaction, 1 neutron (1/0n) + 10/5B → 7/3L + 4/2He (alpha particle) assume that the initial kinetic energy and momentum of the reacting particles are negligible. Calculate the speed of the alpha particle immediately after it leaves the reaction.
Homework...
I have a molecule with a certain kinetic, vibrational, and rotational energy.
It absorbs a photon which excites a vibrational mode.
I want to find an equation that describes how the molecules reaction rate with another molecule might change given the added vibrational energy.
Is there a name...
I want to pump energy into a chemical species to increase its reaction cross section with another.
Typically these species react upon collision when their relative kinetic energy exceeds the activation energy. I want to find a way to increase the reaction rate for interactions at slower...
When is an Elimination 2 reaction more likely to take place than any other reaction (more likely than SN1, SN2, E1)? Details and examples welcome.
I'm reviewing this for a student I'm tutoring and seem to have forgotten what makes E2 happen over the other reactions. Thanks!
Definition/Summary
Between two bodies in contact, there is a pair of Reaction Forces.
They are always equal but opposite (this is precisely Newton's third law), and so it is usual (though slightly misleading) to refer to "the Reaction Force", in the singular.
The component of the Reaction...
Action and reaction are equal and opposite,but why don't they cancell ?...
Unlike other forces, like for example.. it a body is pressed from top and below with a same force.. the body stays there and its said that the forces cancell out.. why not here ?
Homework Statement
according to my book, cycloalkane has no reaction with bromine when it is put into bromine in present of CHCCL3 ... why? as i know , the cycloalkane can undergo susbtituition with bromine . am i right?
Homework Equations
The Attempt at a Solution
Hi I need some help understanding reaction kinetics, and I’m trying to get an overview, so I’d really appreciate some help. I have 3 individual/quite unrelated questions, if you have time to answer one that would be very much appreciated.
1. In what situations dos the Definition of the...
Okay, I need some guidance.
I've tried googling some answers to this question and nothing has really helped me. It's kind of a common sense question, perhaps?
However, my common sense of chemistry reactions is quite low. I am wondering if there is a trick to questions like these...
Greetings all,
I have some questions regarding to chemical reaction between Silicon,Si (wafer) and chemical dissolution. FYI, I'm doing electrochemical ething to fabricate porous Si. Could anyone help me to solve this chemical reactions?
1) Si (silicon wafer) + HF (hydroflouric acid)+...
Hello,
I have a question. Let's say we have isopentane and Cl2 in a substitution reaction. How many different Carbon atoms can chlorine atom bond with? All five or can it substitute with a hydrogen that bonded to methyl brach?
It is an easy question maybe but please answer that is really...
Homework Statement
see attachment
The Attempt at a Solution
From how I see this question, the joint at A has two reactions, one vertical and the other horizontal. The vertical one is zero, and the horizontal one should be 600N left. However, I got the feeling that I might have miss...
what is difference between speed reaction and catalys reaction...like for example nonmetals it will speed up the reaction...and transition metals it will catalys the reaction
Could someone offer a pointer to whether I have the right thinking on this, please?
The way I see it, the K2CO3 would lead to bicarbonate ions, HCO3-, and hydroxides, OH-, upon water dissociation.
Now when those bicarb ions meet the H2PO4- and HPO4-- phosphate ions, I presume you could see...
Dear everybody here,
Here is a problem to solve, from shigley handbook for Machine design, it's about Journal bearing design for the shown shaft in the attachment, i know how to design the journal bearing, but i am a little bit confused about how to get the reaction forces at the two points A...
In lab I am doing a series of single replacement reactions and I am curious how to calculate the heat of reaction for single replacement reactions and what measurements to take so I can calculate it?
I have to say if each reactant is first, second or zeroth order.
Now, I know that usually, we have plots of ln([]) over time. But my teacher wants to trick me.
Here is how I do this:
Take two data points: convert them to [ ] and normal rate (remove the ln() function).
Compare the two...
Homework Statement
Calculate the pH of a solution containing 5.0 g of NaHCo_3 (molar mass = 84.0 g) in 250. mL of H20. NaHCO_3 is amphiprotic. k_a= 4.7x10^{-11}, k_b=2.3x10^{-8}
This is for a General Chemistry II class, for the record.
The Attempt at a Solution
I started...