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
Solid sodium bicarbonate decompose when it's heated above 50 celsius. However, when it is dissolved in water interactions of components changes. So what happens when sodium hydrogen carbonate solution is heated? Does it release carbon dioxide when temperature is above 50...
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...
Homework Statement
Hi all, I am having issues with the following problem. Assistance is greatly appreciated!
Homework EquationsThe Attempt at a Solution
a) The "law of mass action" I know of is just the equilibrium constant, which I wrote in terms of partial pressures at equiilbrium
$$K =...
For a reaction defined as such,
$$A\rightleftharpoons B$$
the equilibrium constant ##K## is defined by ##K = p_B / p_A##, with ##p## denoting the partial pressure (edit: at equilibrium). However, if ##K<<1##, which implies ##p_A >> p_B##, it is said that the backwards reaction dominates and that...
Hi everyone, I'm new here so I hope I'm posting this in the right place.
I'm struggling to duplicate the horizontal reaction forces being generated in an L shaped beam. Typically I like to do hand calculations and verify my answer using Solidworks, but in this case I can't seem to wrap my head...
Hello new to the forum.
I'm a builder by trade and enjoy studying the concepts behind the things I build.
My problem is:
A typical concrete post and base panel with a wooden fence. Unit mass approximately 350kgs including the foundation concrete around the posts.
2.0m wide x 2.0m above...
Homework Statement
Homework Equations
Using dimensional plane in the vertical y and horizontal x.
##\Sigma##Fx = 0
##\Sigma##Fy = 0
##\Sigma##Mz = 0
The Attempt at a Solution
I have detached the 2 members at B and analyze them both separately. The 14 kip force is throwing me off though...
Homework Statement
For the reaction below, the constant pressure heat of reaction is qp = −3256 kJ mol−1 at 25 °C. What is the constant volume heat of reaction, qV , at 25 °C?
16 CO(g) + 33 H2(g) ⟶ C16H34(l) + 16 H2O(l)
Enter your answer in kJ mol−1, rounded to the nearest kilojoule...
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...
Homework Statement
Homework EquationsThe Attempt at a Solution
I need to know the time it takes for the [H+] concentration to be 0.15mol/L. However, the graph gives me the [I2] concentration over time, and I don't know how to convert it to the [H+] concentration. How should I solve the...
Homework Statement
I'm trying to figure out the reaction at D,that's where the system can rotate.
Problem:
A force P of magnitude 90 N is applied to member ACDE, which is supported by a frictionless pin at D and by the cable ABE. Since the cable passes over a small pulley at B, the tension...
Hello, it has been quite some time since my statics class, and I am having a problem determining the reaction forces and moments in a rigid body. I have included a sketch of my problem, and I am hoping someone can help guide me to a solution. I apologize if the sketch is a bit crude.I have a...
Homework Statement
A rope of length L and mass m is attached to the ceiling and folded at mid length. The free end of the rope is held against the ceiling, then dropped at time t=0.
a) Calculate the velocity of the free end as a function of y, its distance from the ceiling.
b) Calculate R...
1. Homework Statement
The chemical reaction is given:
2C2H2 + 5O2 -> 4CO2 + 2 H2O. ΔrH* = -1299 kJ / mol.
How much heat is released when 50 grams of C2H2 is burned?
Homework EquationsThe Attempt at a Solution
First, I convert mass into moles.
M(C2H2) = 2*12+2 = 26 g/mol
n(C2H2) = m/M = 50 g...
Given a large enough energy source (nuclear?)... can I build a rocket that creates its own reaction mass via electron-positron pair production, and then derive thrust by accelerating the charged particles out the back with a magnetic nozzle?
Homework Statement
Which one of the following products will not be obtained in the given Wurtz reaction?
The Attempt at a Solution
Well, (a) will definitely be the major product. We know that this reaction may proceed by a free radical or an ionic mechanism. But what's that got to do with the...
Homework Statement
Which one is more reactive, CO2 or NO2?
Homework Equations
The Attempt at a Solution
I drew the Lewis structures of these species and found there is one delocalized electron in NO2, so I think NO2 is more reactive.
Am I correct?
Hi,
Im trying to find the method for working out the support reaction loads on a beam at given angle.
example: a 6m beam with a point load 600kg or UDl of 100kg/m perpendicular to the beam. Suspended at each end by a chain hoist, "a" and "b". "b" is 2m higher than "a". I believe using angle is...
Please let me know if the following reaction is possible for high energy electrons colliding with neutrons or neutron-rich nuclei:
n+e^{-}\to \Delta^{-}+\nu_e.\tag{1}
If it is forbidden for some conservation law or for some other reason, please give me an explanation why. This reaction is...
Homework Statement
The addition of hydrochloric acid to a silver nitrate solution precipitates silver chloride according to the reaction:
AgNO3(aq)+HCl(aq)→AgCl(s)+HNO3(aq)
When 500 mL of 0.100 MAgNO3 is combined with 500 mL of HCl in a coffee-cup calorimeter, the temperature changes from...
Homework Statement
Fission, the process that supplies energy in nuclear power plants, occurs when a heavy nucleus is split into two medium-sized nuclei. One such reaction occurs when a neutron colliding with a 235U (uranium) nucleus splits that nucleus into a 141Ba (barium) nucleus and a 92Kr...
Hi, I've been wondering about this a lot and I didn't find a satisfactory answer by myself.
My professor said that in order to promote a fission reaction you need to provide a certain amount of energy (like in a chemical reaction you need to overcome the activation energy) and the easiest way...
Homework Statement
A motorist is traveling at 10m/s in a car whose maximum deceleration rate is 5.0 m/s^2
The effective reaction time between seeing a hazard and starting to brake is 0.5s
Calculate the thinking distance for the drover ar this speed (ie the distance traveled during his...
Homework Statement
If you had a solution of Magnesium carbonate, what results would you expect from the following four tests: Precipitation Test, Flame Test, Benedicts Reagents Test, Dilute Acid Test.
Could someone take a look at my reasoning to how the Magnesium Carbonate would react under...
<< Thread moved from the technical forums, so no Homework Help Template is shown >>
I have mind boggling problem, trying to distinguish between Dynamic reaction versus Coriolis acceleration of thin hoop.
Problem: A thin, hoop of mass m and radius r spins at the constant rate ω 1 about an axle...
Homework Statement
What is the product of acetlyene and HOCl reaction?
I gathered that Cl acts as electrophile and so (HCOH)=CHCl is formed.
Now two things can happen, it could tautomerize to keto form since enol form is unstable, or another molecule of HOCl can add itself, if it adds again...
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 (...
I am not talking about the reactions of simple atoms in chemistry, I am speaking, for example deuterium, heavy water, isotopes of hydrogen, oxygen, carbon, etc.I would like to know how to calculate when two atoms merge, to know mathematically what atom will form, example deuterium + deuterium =...
The DTT project proposal talks about a D-D reaction inside the future tokamak that is going to be built in Italy, Frascati. Which is the reason of this choise? The cross section is smaller than the D-T reaction one, and neutrons are less energetic. How this influences heat and particle exhaust...
Homework Statement
To stop a car, first you require a certain reaction time to begin braking; then the car slows down under constant breaking decelaration. Suppose that the total distance moved by the car during these two phases is 56.7 m when its initial speed was 80.5 km/h and 24.4 m when its...
How do i suppose to determine the uncertainty for the slope of my Static friction against normal reaction graph?
My data for static friction and normal force has the uncertainty of +/- 0.0001
The uncertainty is too small for me to draw airbox/bar in the graph to draw the max and min slope...
Hi,
I have been searching d-d reaction cross-section at higher energies up to 10 MeV. I checked ENDF database, however, I could not find any data. Do anyone offer a source from which I can get d-d cross-section data?
thanks in advance.
Homework Statement
Suppose there is a chemical reaction : N2 + 3H2 = 2NH3
The following things are written in my book :
rate of disappearance of H2 = - Δ / Δt
rate of reaction wrt H2 = - 1/3 * Δ / Δt
My question is that why can't we write rate of reaction = rate of disappearance of H2 ? In...
Homework Statement
My question is not a homework problem. I am having difficulty in understanding the concept oof contact forces.
Homework Equations
What I don't understand is that when two bodies A and B are in contact and left on a frictionless surface, they apply normal reactions on each...
Homework Statement
Calculate E cell for the following reaction at 25deg celcius
3 CU(s) + 2 MnO4-(aq) + 8 H+(aq) →2 MnO2(s) + 3 CU^2+(aq) + 4 H2O(l)
Given: [CU^2+] = 0.010M, [MnO4-] = 2.0M, [H+] = 1.0M
I’ve posted a picture of my work, if someone could just let me know if I answered the...
Homework Statement
2 IO3−(aq) + 6 H+(aq) + 10 I−(aq) →6 I2(s) + 6 H2O(l)
I didn’t want to re-type all of this up but I uploaded of picture of my work for this problem. I was just wondering if I completed it correctly and if not if someone could guide me in the right direction. Thank you!
This may be bit weird but really do we get any product after the reaction of 118 elements of the periodic table.We know masses of reactant = masses of product.But no so in nuclear fission and fusion.Anyhow finally what might be that product?and what is going to be its state.Please explain me...
Homework Statement
I'm having a hard time finding the support reactions R_{fx} ; R_{fy} ; R_{kx} ; R_{ky} in this truss.
2. The attempt at a solution
I got four equations using the equilibrium conditions (sum of forces along x and y ; sum of moments on F and on C) but the system doesn't...
I have obtained an experimental setup of a Marx bank which has electrolytic liquid resistors. In the tubing of the resistors are various strength solutions of copper sulfate. I was told that the electrodes are copper but there appears to be some sort of plating or other reaction occurring...
I know that normal force is not a reaction force to the gravitational force;
- First, because the gravitational force is from Earth on the object (action force) thus the reaction of force is simply form the object on Earth according to Newton's third law.
- Also because in certain situations...
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...
Does anyone know of any studies into exactly how much various metals reflect or absorb microwaves with relationship to the microwaves wavelength and ideally theyt compounds too?
Homework Statement
this question is about the organic reactions shown in the diagram. ( diagram shows that butan2one is reaction with a reagent P and Q and then reagent R and forms propanoic acid and iodoform)
a)name the reagents P and Q used in reaction 1.
b) identify the reagent R used in...
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"...
Homework Statement
If you have an object say in a vertical pipe, which only has a gravitational force acting on it would the reaction forces only be friction forces?
If this is the case how would you calculate the forces? would you calculate the friction force using the friction coefficient or...
What would the theoretical maximum possible speed be for a platform on a horizontal air-bearing (friction-less), if the only propulsion was a spring powered machine gun with unlimited steel balls? The balls go one way, the platform moves proportionally in the opposite direction. Ignore inertia...
Homework Statement
Homework EquationsThe Attempt at a Solution
C=C double bonds means that it is not an Alkane because an Alkane is saturated hydrocarbon. So the answer should be from A, B or C.