Environmental Chemistry


Urea is widely known as carbamide, The diamide form of carbonic acid. Urea is popularly useful as a fertilizer, a feed supplement, and a starting material to manufacture drugs and plastics. It is a colourless substance that exists in the crystalline form. It melts at \(132.7^{\circ}C\)  and decomposes before the boiling point of urea. The chief and product of metabolic protein Break down in few fishes and all the major mammals is urea.

Urea is present in the milk, bile, blood, and perspiration of the mammals. During the process of protein Breakdown, all of the amino groups \(NH_{2}\) and naturally out from the amino acids containing proteins.

Furthermore, these groups convert into ammonia \(NH_{3}\), which is also toxic to the body. So as to protect the body from it, the human liver converts it into urea. The urea then passes through the kidneys and is out in the form of urine.



What is Urea?

The nitrogenous compound forming in the liver is urea. The chemical formula of urea is \(CH_{4}N_{2}O\). The other name of urea is Carbamide or Ureophil. The compound forming is the final product of protein metabolism. Urea is a waste product and it has no psychological function. Urea dissolves in blood and the kidney excretes it in the urine. Carbonyl is the functional group that connects the two \(NH_{2}\)  groups of this organic compound.

Urea is non-toxic and easily dissolves in water. Urea has no smell and it also doesn’t have any colour. It is commonly in use in fertilizers and is also an essential raw material in industries. Hilaire Marin Rouelle, A French scientist from 1773, Separated urea from urine. Later in the year  1828, a German scientist, Friedrich Wohler, officially begun to prepare it from ammonium cyanate.

We prepare urea commercially in larger amounts from both liquid ammonia and liquid carbon dioxide. When these materials combine under elevated temperature and high pressure, they form ammonium carbamate. It gives water and urea when it decomposes at lower pressure.

Urea in the Human Body

Urea is a liquid waste that is not necessary for the body. From the bloodstream, the kidneys eliminate the wastes. In humans, it is a yellowish liquid that contains water and many other chemical components such as hormones, carbohydrates, uric acid, and traces of enzymes.

The lungs, skin, and kidneys are the vital excretory organs in the body. These are the only organs that remove the toxins and toxic products from the body. The lungs remove excess carbon dioxide on the other hand skin removes excess salts and water. While the kidneys remove excess salts, water, and urea The formation of urea takes place when the dietary proteins turn into amino acids during the process of digestion, which goes to the liver. The liver breaks down the excess acids to ammonia. Further, the conversion to urea takes place, which is less toxic.

Structure of Urea

Urea has no psychological function. It is a waste product in the body. It excretes out as urine but before dissolves in the blood and kidney. Urea is an organic compound that consists of two different \(NH_{2}\)  groups which are in relation to the carbonyl functional group. Urea dissolves In water as it is a non-toxic substance.  Not only urea is colourless but also it has no smell.

The carbonyl Group of ammonia has two Amide groups. This is the origin of the name carbamide, which forms from carboxylic and Amide. In a carbonyl group The carbon atom double bonds to an oxygen atom. In the amide group, The nitrogen atom attaches to two different hydrogen atoms. When we put these two Amide groups in bond with the carbonyl group, The formation of urea takes place.

Properties of Urea

Urea contains the following atoms.

  1. 4 hydrogen
  2. 1 carbon
  3. 1 oxygen
  4. 2 nitrogen

The molecular weight/ molar mass/urea mass of urea is \(60.06 \frac{g}{mol}\) and its density is \(1.32 \frac{g}{cm^{3}}\). It appears as a white solid and its melting point is \(133^{\circ}C\). Urea mainly consists of nitrogen, carbon, and oxygen. It turns into the urine in its concentrate form. Urea is a crystalline compound having a nitrogen content of around 46%, when in a dry state.

In the United States, every year 1 million pounds of urea is in process. Most of which is useful in the fertilizers, to make their nitrogen content water-soluble. Urea is very much useful in plastics and loose, explosive components, animal feedstock, and expensive commercial products.

Uses of Urea

Urea is useful in manufacturing melamine. It is also useful as a brownie agent for pretzels and in hair removal creams and dish soaps. With the help of the urea breath test, urea can detect the bacteria in the stomach. Urea is very much in use in creams, ointments Which are useful for rehydration.

In the manufacturing industry urea is in use for high explosive materials like urea nitrate. It is also in use as a stabilizer, in nitro Cellulose explosive products. In lanthanide chemistry, it is useful as an important read it. One of the major uses of urea is in nitrogen release fertilizer, which makes the product water-soluble.

Detection of Urea

Urease Test

Materials required

  • Urease powder
  • Dropper
  • Spatula
  • 1% acetic acid
  • Urine sample
  • 2% of \(Na_{2}CO_{3}\)
  • Measuring cylinder
  • Phenol red indicator


  1. First, take a clean and dry test-tube.
  2. Then with a measuring cylinder measure and then add 5ML urine sample in the test-tube.
  3. Add 4 to 5 drops of Phenol Red indicator to the test-tube using a dropper.
  4. With another dropper, add drops of 2% \(Na_{2}CO_{3}\) solution.
  5. Add \(Na_{2}CO_{3}\) dropwise until the disappearing of pink
  6. Add a little amount of urease powder with the help of a spatula in the urine sample test tube.
  7. Then shake the test-tube slowly to mix the urease powder.
  8. Hence observe the changes

We observe that the indication of the disappearance of red and pink colour gives the existence of urea in the given sample.

FAQs about Urea 

Q1.Are urea and urine the same?

Answer: Most of the living organisms produce a waste product which is known as urea. Urea is the main organic component in human urine. The liver converts ammonia to non-toxic compounds which is urea and it can transform safely to the kidneys in the blood where extract in the urine.

Q2.What are the uses of urea?

Answer: Urea is widely in use as a supplement to fertilizer and is also a starting material for producing plastic and manufacturing medicines.

Q3.How does urea affect the skin?

Answer: Urea is very essential in water biding as it is a nitrogen compound and also has mild exfoliating properties for skin in limited quantity. It can exfoliate skin in large amounts but it can also cause irritation if the usage is in larger quantities. urea is also in use in cosmetic manufacturing as it works as an absorbent on the skin.

Q4. How much time does urea take to act in a fertilizer?

Answer: When the soil is on track condition, we cannot see any reaction. But with the soil moisture, the urea hydrolyses itself, and further the conversion into carbon dioxide and ammonium takes place. The complete process takes 2 to 4 days, specifically on the high pH soils. But, we have to be careful about the soil, before we use urea in it. One must conduct a soil test prior, to make things easier.

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