What is Chemical reactions: Definition and 77 Discussions
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.
I was wondering how come when ever there's a question like aluminum reacts with bromine it is usually written like Al + Br2? or Potassium reacts with oxygen is K + O2?
How do we know when there's 2 of them?? Is there like a special rule? Why isn't there K2 or Al2??
Homework Statement
When copper metal is placed in a beaker containing a solution of silver nitrate, a reaction occurs which can be represented by the following equation:
2AgNO3(aq) + Cu(s) -----> Cu(NO3)2(aq) + 2Ag(s)
a) Give the net ionic equation to represent this reaction occurring...
like mixing household chemicals together to get a cool reaction to help my brother for the science fair? please don't say baking soda and vinegar half the school is doing that for a volcano.
Homework Statement
Styrene is a Hydrocarbon. If 0.438g of Styrene is burned in Oxygen and produces 1.481g of CO2 and 0.303g of H20, what is the empirical formula of styrene?
Homework Equations
The Attempt at a Solution
No. of moles of CO2 - 1.481g / 44.0107g/mol = 0.0337mol
No...
I realize that to calculate heat being released and contained during nuclear reaction you must understand the difference between its product mass and reactant mass by using *E=mc2.* My Question pertains to the heat being released during a chemical reaction... Is Mass conserved in this chemical...
Aspirin, C9 H8 O4 (molar mass 180.2g/mol), a drug used to relieve minor aches and pains, is prepared by the following reaction:
C7 H6 O3 (s) + C4 H6 O3 (l) --> C9 H8 O4 (s) + C2 H4 O2 (l)
If you need to prepare 45.0g of aspirin, and yield for the reaction is 85% how many grams of salicylic...
hi
i have the following reaction
isobutyric acid + 2-methoxyethanol <-> 2-methoxyethyl-2-methylpropanoate
but i don't know all of the by-products.
please help thanks
edit: i think is only water and some unreacted reactants?
i can't do this home work. i REALLY suck at physics, this is why I am here. can someone help me pleasse? :)
1#to combust completely 7g of iron, 2L of oxygen is needed. for each of the following state if any unreacred iron rests after combustion and if it does how much:
a) 2g of iron and...
A simple question really. Does acceleration affect the rate of a chemicall reaction. I.e if I was to put some test (chemical) experiment aboard a suitable craft and accelerate it to a high velocity, would the reaction occur at the same rate as it would at rest - ignoring relativistic effects...
I can not seem to understand what happens when you react ammonium with certain compounds. For example NH3 + Cu(NO3)2 = ?. How am I supposed to do this?
Homework Statement
I basically have 4 sets of solutions which I have to write the chemical reactions for. I already figured out the chemical formulas for the reactants, and just need help determining the final products. I know how to balance, and just need help determining the products...
hello, i hope someone can help me.
i have a few questions.
The elements sulfur and chlorine react to give disulfur dichloride according to the equation:
S8 + 4Cl2 --> 4S2Cl2.
There are 0.5987 mol S8.
a) How many moles of Cl2 are needed for complete reaction?
b) What mass of S2Cl2 in...
Hello,
I am a A level student. I find difficulties with different chemical reactions.
Is there any simple way of predicting chemical reactions.
Is there any basic principles that can be followed instead of memorising chemical equations?
Different chemical reactions occurs in different...
Help me understand please
0.6 mole of O2, 0.8 mole of CO and 0.5 mole of CO2 are added to a 2-L container. The system is heated and 0.15 mole of CO2 is formed.
Does that mean that on top of the initial 0.5 mole of CO2 an additional 0.15 mole of CO2 is formed or does that mean that in total...
Working a problem in Greenburgs "Advanced Eng. Mathematics", #8 page 170. Two substances w/ concentration x(t) and y(t), react to form a 3rd substance w/ concentration z(t). The reaction is governed by the system
x’+ αx = 0
z’= βy
x + y + z = γ
solve for x(t), y(t), and Z(t) subject to...
Hi, i woud like to ask one thing...
Discuss the idea that the standard of living in a society might be measured in units of kJ/person available in that society.
...just instruct me how to do this question i mean what answer they
are looking for...
Hello, I just need some help on these questions and some explaining.
I need help writing the condensed word equation for these chemical equations:
A) Li + Hg(ClO)_2 \xrightarrow~Hg + LiClO
Maybe: Lithium + Mercury(II) Chlorine oxide ------> Lithium Carbonate
B) C_8H_1_8 + O_2...
Hello, I just need some help on these questions and some explaining.
What to do:
> Balance each of the following chemical equations.
> Identify the type of chemical reaction (Decompostion, Combustion and Synthesis)
> Write the condensed word equation
A) Li + Hg(ClO)_2 \xrightarrow~Hg...
general "quantities in chemical reactions" questions
hi,
im in high school, and we are currently doing a unit of chemistry on quantities in chemical reactions, and there are a few things i don't get, and i was wondering if anyone could show me a formula or an example, on calculating the...
Hi
I got two questions regarding the following chemical:
i) P_4 + 5O_2 -----> P_4 O_10
ii) P_4 O_10 + 6H_2O -----> 4H3 PO_4
How many grams of P_4 O_10 are formed in i) if there is 35 grams of P_4 ??
How many grams of H_3 PO_10 are formed in ii) if I have 35 grams of P_4 ...
A Rule of Thumb:
"Higher Electronegativity seeks bonding with Lower Electronegativity"
Before completing my PhD in organic chemistry, with a minor in inorganic, some 20 yrs ago, I realized that the main mechanism for most organic reactions and most inorganic reactions was one of negative...