One gram of water at gets converted into steam at by gaining 536 Cal of heat. Same amount of heat when taken out of steam converts it back to water. So, vaporization of water is also a reversible process.

N.B. If butter is melted to become a liquid, it is a reversible change because it can become solid again by freezing.

Reversible changes A reversible change might change how a material looks or feels, but it doesn’t create new materials. Examples of reversible reactions include dissolving, evaporation, melting and freezing.

Matthew Johnson, Math major and autodidact. Unless you consider ‘toast’ bread that was simply warmed and not toasted (which I call ‘raw toast’), then clearly it is irreversible. You have by toasting changed the chemistry in an irreversible way. Heat making chemical changes is not “infinitely close to equilibrium”.

Medical Definition of irreversible : incapable of being reversed : not reversible an irreversible medical procedure : as.

Reversible changes: The changes which can be brought back to its original form are known as reversible changes. For example, melting of wax and stretching of a rubber band. Irreversible changes: The changes in which the matter cannot be brought back to its original state are known as irreversible changes.

Once the chemical properties of a substance are changed, it becomes another substance. Thus, it cannot return to its original state. But physical changes are also not reversible such a growth in height, cracking of egg.

Like, turning of water into ice is an example of reversible changes but growth in height is an irreversible change. Chemical changes are changes that occur in the chemical properties of the substance like its flammability, radioactivity, etc. All chemical changes are irreversible changes.

Irreversible chemical reactions can occur in only one direction. The reactants can change to the products, but the products cannot change back to the reactants. Reversible chemical reactions can occur in both directions. The reactants can change to the products, and the products can also change back to the reactants.

Examples of reversible reactions

• Ammonium chloride is a white solid. It breaks down when heated, forming ammonia and hydrogen chloride.
• Ammonium chloride ⇌ ammonia + hydrogen chloride.
• The symbol ⇌ has two half arrowheads, one pointing in each direction. It is used in equations that model reversible reactions:

Explain why chemical reactions in the body are often irreversible. When products of a reaction are continuously taken away from the sight of the reaction it is unable to present for the reverse reaction. Furthermore, reaction involving energy release will not go backwards unless energy is put into them.

Reversible reactions never go to completion because they attain equilibrium after a certain time. So, the concentration of reactants and products is stable, it neither increases nor decreases.

Chemical reactions that take place inside living things are called biochemical reactions . The sum of all the biochemical reactions in an organism is called metabolism . Metabolism includes both exothermic (energy-releasing) chemical reactions and endothermicno post (energy-absorbing) chemical reactions.

37 thousand billion billion chemical reactions

The types of chemical reaction are: Combination reaction. Decomposition reaction. Displacement reaction.

The five basic types of chemical reactions are combination, decomposition, single-replacement, double-replacement, and combustion. Analyzing the reactants and products of a given reaction will allow you to place it into one of these categories. Some reactions will fit into more than one category.

Examples of chemical reactions in everyday life include photosynthesis, rust, baking, digestion, combustion, chemical batteries, fermentation, and washing with soap and water.

The mixing of soap and water is a physical rather than a chemical reaction.

In human body the most common or you can say usual chemical reaction is respiration. Respiration is simply gaseous exchange, with release of energy. It can be stated as in oxidation reaction, where which oxygen from air get absorbed and mixed with food and then it produces energy.

What’s the most deadly substance?

• Chlorine trifluoride (Substance N)- A nasty Nazi development.
• Azidoazide Azide – This is considered by many to be the most explosive compound ever created.
• Dimethyl Cadmium – This is considered by some to be the most toxic chemical in the world.

So here is a list of substances that are more poisonous than their LD50 values might indicate.

• Botulinum toxins. Even though some of them are used in the cosmetic industry (including in botox), the botulinum family of neurotoxins includes the most toxic substances known to man.
• Snake toxins.
• Arsenic.
• Polonium-210.
• Mercury.

The world’s strongest superacid is fluoroantimonic acid. Fluoroantimonic acid is a mixture of hydrofluoric acid and antimony pentafluoride. The carbonane superacids are the strongest solo acids.

But surprisingly, amongst all the toxic, corrosive, and otherwise nasty gases that exist in industry, the most deadly of them all is the one we breathe in the most – nitrogen. Nitrogen (N2) is an inert and invisible gas that makes up about 78% (by volume) of the air we breathe.

Carbon monoxide (CO) is a gas that can kill you quickly. It is called the “silent killer” because it is colorless, odorless, tasteless and non- irritating.

Of all the species in the world, the largest—and most dangerous—is the saltwater crocodile. These ferocious killers can grow up to 23 feet in length, weigh more than a ton, and are known to kill hundreds each year, with crocodiles as a whole responsible for more human fatalities annually than sharks.

So you might think that breathing 100 percent oxygen would be good for us — but actually it can be harmful. So, the short answer is, pure oxygen is generally bad, and sometimes toxic.

It’s absolutely true: pure oxygen can give rise to feelings of euphoria. Not for the people who inhale it from oxygen vending machines – which, as reported this week, are now being tested in nightclubs – but for the people who sell it.

Inhaled and exhaled air

Gas	% in inhaled air	% in exhaled air
Oxygen	21	16
Carbon dioxide	0.04	4
Nitrogen	79	79
NB These figures are approximate.