# 2.3 Chemical reactions  (Page 3/24)

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In the second example, ammonia is catabolized into its smaller components, and the potential energy that had been stored in its bonds is released. Such reactions are referred to as decomposition reactions. A decomposition reaction    is a chemical reaction that breaks down or “de-composes” something larger into its constituent parts (see [link] b ). The general equation for a decomposition reaction is: $\text{AB}\to \text{A}+\text{B}$ .

An exchange reaction    is a chemical reaction in which both synthesis and decomposition occur, chemical bonds are both formed and broken, and chemical energy is absorbed, stored, and released (see [link] c ). The simplest form of an exchange reaction might be: $\text{A}+\text{BC}\to \text{AB}+\text{C}$ . Notice that, to produce these products, B and C had to break apart in a decomposition reaction, whereas A and B had to bond in a synthesis reaction. A more complex exchange reaction might be: $\text{AB}+\text{CD}\to \text{AC}+\text{BD}$ . Another example might be: $\text{AB}+\text{CD}\to \text{AD}+\text{BC}$ .

In theory, any chemical reaction can proceed in either direction under the right conditions. Reactants may synthesize into a product that is later decomposed. Reversibility is also a quality of exchange reactions. For instance, $\text{A}+\text{BC}\to \text{AB}+\text{C}$ could then reverse to $\text{AB}+\text{C}\to \text{A}+\text{BC}$ . This reversibility of a chemical reaction is indicated with a double arrow: $\text{A}+\text{BC}⇄\text{AB}+\text{C}$ . Still, in the human body, many chemical reactions do proceed in a predictable direction, either one way or the other. You can think of this more predictable path as the path of least resistance because, typically, the alternate direction requires more energy.

## Factors influencing the rate of chemical reactions

If you pour vinegar into baking soda, the reaction is instantaneous; the concoction will bubble and fizz. But many chemical reactions take time. A variety of factors influence the rate of chemical reactions. This section, however, will consider only the most important in human functioning.

## Properties of the reactants

If chemical reactions are to occur quickly, the atoms in the reactants have to have easy access to one another. Thus, the greater the surface area of the reactants, the more readily they will interact. When you pop a cube of cheese into your mouth, you chew it before you swallow it. Among other things, chewing increases the surface area of the food so that digestive chemicals can more easily get at it. As a general rule, gases tend to react faster than liquids or solids, again because it takes energy to separate particles of a substance, and gases by definition already have space between their particles. Similarly, the larger the molecule, the greater the number of total bonds, so reactions involving smaller molecules, with fewer total bonds, would be expected to proceed faster.

In addition, recall that some elements are more reactive than others. Reactions that involve highly reactive elements like hydrogen proceed more quickly than reactions that involve less reactive elements. Reactions involving stable elements like helium are not likely to happen at all.

What is anatomy
anatomy is the study of the different organs of the body being internal and external organ
Cyrille
is't possible for non-identical twins to have different father ? ?
Cyrille
ANATOMY is the scientific study of the structure of human or animal bodies.
jagriti
Anatomy is the branch of science concerned with the bodily structure of humans, animals, and other living organisms, especially as revealed by dissection and the separation of parts.
Brightone
anatomy is the branch of science that duty with the study structure of the human and living organisms.
Masiame
examples of lymph nodes
Clusters of lymph nodes are found in the neck, axilla (underarm), chest, abdomen, and groin. For example, there are about 20-40 lymph nodes in the axilla. Also called lymph gland. Anatomy of the lymph system, showing the lymph vessels and lymph organs including lymph nodes, tonsils, thymus, spleen,
Excellent 😊
Sharon
in part of body where did we get medulla
Are you referring to the medulla oblongata? In which case, this is a part of the brain, located at the brain stem. It controls a lot of our unconscious behaviors such as motor coordination, breathing, etc.. But medulla generally refers to an innermost structure, so it can be found in hair or kidneys
Elliot
How does blood circulate in the upper limbs
From the aortic arch, blood is supplied to the brain via the R and L carotid arteries. To supply the upper limbs, blood goes to the R and L subclavian arteries, axillary, radial/ulnar, palmar and carpal arteries.
Elliot
describe the muscles found in the heart
myocardial
Kenndy
thank you very much
Atotwe
asalamu aleikum
Cabdala
waalekum salam
Tifu
types of connective tissues?
Tifu
what is a muscular system and details about it
what is the type of homones responseble for blenking of eyes
what are the functions of cell?
how does the femur act as a lever?
what is stumac
What is phagocytosis
Phagocytosis, process by which certain living cells called phagocyte
It is the process that is carried out by the immune system of the body, that certain specialized immune cells (macrophages, Nks, dendritic cells, etc) that engulf and neutralize the foreign substances that invades the body.
Wesley
So that they can be predicate out of the body.
Wesley
phagocytosis is the process by which living cell or yh plasma membrane engulf large molecules into it internal environment ... it also known as food feeding
Boateng
all that you are say what does it mean?
Dzah
simply is the way the immune system fights foreign bodies by engulfing them..
Dzah
by the help of the immune cells...
Dzah
The process by which a cell engulfs particles such as bacteria, other microorganisms, debris of dead cell.e.g: neutrophils and monocytes (types of white blood cells)
Tifu
what are the six types of connective tissues
loose and dense , cartilage and bone , blood and lymph
Queen
describe the structure of the liver
what is specific name for spinal cord
what is the best description for skeletal muscular
Stanley
what is the best description for skeletal muscular
Stanley
costs of bones of skeleton, their joint s and voluntary
grace
what are examples of long bones
grace
example of long bones will be the femur tibia and humerus and even radius
Nina
so basically long bones are mostly in you hands and feets
Nina
skeletal muscular are voluntary and are attached to the bone by tendon which help maintain the posture and position of the body and it also protects internal organs in the abdominal region
Nina
The specific name for spinal cord is coccygeal segment
Sandra
what are the hormones responseble for blenking of eyes.
Moses
Smallest unit of life
cell
The cell is the smallest structural and functional unit of living organisms, which can exist on its own. Therefore, it is sometimes called the building block of life. Some organisms, such as bacteria or yeast, are unicellular—consisting only of a single cell—while others, for instance, mammalians, a
cells are the building blocks of life
Stanley