# 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.

Describe the sequence of injuries that may occur if the extended, weight-bearing knee receives a very strong blow to the lateral side of the knee.
what is anotomy and waht is phesiology
anatomy is classified the origin physiology is functional of origin
oHo
classified origin functional of origin
Sheryl
Anatomy is the origin of the human body Physiology is the function of the human body
Rose
Differentiate between pharmacist and apothecary
What is metatarsal
bone of the foot is known as metatarsal
Patrick
yes 👆 right
Sneha
metatarsal (foot bone).....👍
Rishi
what is the meaning for cadavers
Malar
yes metatarsal are foot bone
Rakiya
the term "mental" pertain to which of the following a. chin b.navel c. ear d. nose e. skull
a
Lina
chin
Sneha
hi
Mohamed
skull
Monica
skull
Peter
chin
Kelly
skull
Juma
skull
Gul
skull
Laraib
skull
anwaar
skull
Nirmala
skull
Tessmol
chin
Derrick
mental chin nerve
Katarzyna
e. skull
Jennifer
skull
prince
e. skull
Natasha
It's not skull but chin
mwango
the skull
Rakiya
what are the three many components of the lymphatic system?
those are...... organ, tissue and blood capillary or vessals
Juma
anatomical terms and use them appropriatly in the language of anatomy of anterior body landmarks
what is human anatomy?
Sa
what is the study of how the body functions?
Bright
What is human anatomy
Sherifat
human antomy is the body of structure
Malar
is the study of human body
Rakiya
what is abdomipelvic cavity?
Includes all organs within the abdomen(stomach,intestines) and those from the pelvic region hence the name... abdomipelvic
Maureen
where can we find the short bones
Carpal bones are examples of short bones
Dara
what is blood supply
Chidi
on upper limb and lower limb
Juma
carpal bones
Priya
during pregnancy which would more increase size the mothers abdominal or pelvic cavity?
pelvic cavity I think
Priya
What is anatomical position
Nwoye
pelvic
Maureen
@ Nwoye... when standing erect, feet parallel, arms hanging at the sides with palms facing forward
Maureen
The pelvic cavity
Rakiya
pelvic
Malar
define the main directional terms of the body
during physical exercise respiratory rate increace two student are discussing the mechanisms involved. student A claim they are positive feedback and student B claim negative feedback do you agree with student A or B and why
cris
what is the physiology of circulation
Chidi
please I mean the physiology of criculation
Chidi
blood flow refers to the movement of blood through the vessels from arteries to the capillaries and then to the veins
Laraib
the heart&the lungs
Rakiya
during pregnancy, which would more size the mother's abdominal or pelvic cavity? explain
list and define the three plane of devision of the body
cris
complete the following statements using correct directional terms for human being. 1. the navel is________to the nose 2. the heart is______to the breastbone(sternum) 3 the ankle is______to the knee 4 the ear is______to the eyes.
cris
1. superior 2. posterior 3. superior 4. lateral
Mnm
anterior fuerior
Chidi
inferior medial posterior lateral we
Susan
name the system of the body and its function
11 system are human body 1.integumentary system 2. skeletal system 3. muscular system 4. nervous system 5. endocrine system 6. cardiovascular system 7. lymphatic system 8. respiratory system 9. digestive system 10. urinary system 11. reproductive system male and female.
Vineeta
during pregnancy, which would more size the mother's abdominal or pelvic cavity? explain
cris
how the body maintain hormeostasis in terms of bloodglucose level
It releases hormones from the pancreas insulin and glucagon
TONY