Wikipedia

Search results

Saturday, 28 March 2015

Common Household Chemicals That May Be Dangerous

Air Fresheners - Air fresheners may contain any of a number of dangerous chemicals. Formaldehyde irritates the lungs and mucous membranes and may cause cancer. Petroleum distillates are flammable, irritate the eyes, skin, and lungs, and may cause fatal pulmonary edema in sensitive individuals. Some air fresheners contain p-dichlorobenzene, which is a toxic irritant. The aerosol propellants used in some products may be flammable and may cause nervous system damage if inhaled.

Ammonia - Ammonia is a volatile compound that can irritate the respiratory system and mucous membranes if inhaled, can cause a chemical burn if it is spilled on skin, and will react with chlorinated products (e.g., bleach) to produce deadly chloramine gas.

Anti freeze - Antifreeze is ethylene glycol, a chemical which is poisonous if swallowed. Breathing it can cause dizziness. Drinking antifreeze can cause serious brain, heart, kidney, and other internal organ damage. Ethylene glycol has a sweet flavor, so it is attractive to kids and pets. Antifreeze typically contains a chemical to make it taste bad, but the flavor is not always a sufficient deterrent. The sweet smell is enough to lure pets.

Bleach - Household bleach contains sodium hypochlorite, a chemical that can cause irritation and damage to the skin and respiratory system if inhaled or spilled on the skin. Never mix bleach with ammonia or with toilet bowl cleaners or drain cleaners, as dangerous and possibly deadly fumes may be produced.

Drain Cleaners - Drain cleaners typically contain lye (sodium hydroxide) or sulfuric acid. Either chemical is capable of causing an extremely serious chemical burn if splashed on the skin. They are toxic to drink. Splashing drain cleaner in the eyes may cause blindness.

Laundry Detergent - Laundry detergents contain a variety of chemicals. Ingestion of cationic agents may cause nausea, vomiting, convulsion, and coma. Non-ionic detergents are irritants. Many people experience chemical sensitivity to dyes and perfumes present in some detergents.

Mothballs - Mothballs are either p-dichlorobenzene or naphthalene. Both chemicals are toxic and known to cause dizziness, headaches, and irritation to the eyes, skin, and respiratory system. Prolonged exposure can lead to liver damage and cataract formation.

Motor Oil - Exposure to the hydrocarbons in motor oil can cause cancer. Many people are unaware that motor oil contains heavy metals, which can damage the nervous system and other organ systems.

Oven Cleaner - The danger from oven cleaner depends on its composition. Some oven cleaners contain sodium hydroxide or potassium hydroxide, which are extremely corrosive strong bases. These chemicals can be deadly if swallowed. They can cause chemical burns on the skin or in the lungs if the fumes are inhaled.

Rat Poison - Rat poisons (rodenticides) are less lethal than they used to be, but remain poisonous to people and pets. Most rodenticides contain warfarin, a chemical which causes internal bleeding if ingested.

Windshield Wiper Fluid - Wiper fluid is toxic if you drink it, plus some of the poisonous chemicals are absorbed through skin, so it is toxic to touch. Swallowing ethylene glycol can cause brain, heart, and kidney damage, and possibly death. Inhalation can cause dizziness. The methanol in wiper fluid can be absorbed through the skin, inhaled, or ingested. Methanol damages brain, liver, and kidneys and can cause blindness. The isopropyl alcohol acts as a central nervous system depressant, causing drowsiness, unconsciousness, and potentially death.



Tuesday, 25 March 2014

Polyester



Polyester:-
Polyester is a term often defined as “long-chain polymers chemically composed of at least 85% by weight of an ester and a dihydric alcohol and a terephthalic acid”. In other words, it means the linking of several esters within the fibers. Reaction of alcohol with carboxylic acid results in the formation of esters.
Polyester also refers to the various polymers in which the backbones are formed by the “esterification condensation of polyfunctional alcohols and acids”.
Polyester can also be classified as saturated and unsaturated polyesters.
Saturated polyesters refer to that family of polyesters in which the polyester backbones are saturated. They are thus not as reactive as unsaturated polyesters. They consist of low molecular weight liquids used as plasticizers and as reactants in forming urethane polymers, and linear, high molecular weight thermoplastics such as polyethylene terephthalate (Dacron and Mylar). Usual reactants for the saturated polyesters are a glycol and an acid or anhydride.
Unsaturated polyesters refer to that family of polyesters in which the backbone consists of alkyl thermosetting resins characterized by vinyl unsaturation. They are mostly used in reinforced plastics. These are the most widely used and economical family of resins.
Characteristics of polyester
  • Polyester fabrics and fibers are extremely strong.
  • Polyester is very durable: resistant to most chemicals, stretching and shrinking, wrinkle resistant, mildew and abrasion resistant.
  • Polyester is hydrophobic in nature and quick drying. It can be used for insulation by manufacturing hollow fibers.
  • Polyester retains its shape and hence is good for making outdoor clothing for harsh climates.
  • It is easily washed and dried.
Uses of Polyester
The most popular and one of the earliest uses of polyester was to make polyester suits – all the rage in the 70s. Polyester clothes were very popular. Due to its strength and tenacity polyester was also used to make ropes in industries. PET bottles are today one of the most popular uses of polyester.

Thursday, 10 October 2013

Bio-Fuel

                                                                  BIO FUEL
Biofuels are fuels largely derived from living organisms that use the sun as their main energy input. Energy may be put into planting, fertilizing, harvesting, and processing the crops, but most of the energy, in the final plant product, comes from the sun. Through the process of photosynthesis plants convert solar energy into chemical forms of energy (carbohydrates, fats, etc.). Plant convert solar energy into a chemical form more usable as a fuel. Biofuels are considered carbon neutral. That is, they release no net amount of carbon dioxide into the atmosphere.This because the carbon dioxide that is released during combustion was originally absorbed from the atmosphere during the process of photosynthesis.Hence, no extra CO2 is pumped into the atmosphere The process of photosynthesis can be summarised by the equation below.
6H2O + 6CO2 => C6H12O6 + 6O2
Palm oil is used to produce biofuel.  . A process known as transesterification is commonly used to produce biodiesel. Chemically, transesterification is the process of exchanging the alkyl group of an ester with another alkyl group, from a different alcohol. Vegetable oil contains fatty acids bonded to glycerol to form triglycerides. In the case of biodiesel, a vegetable oil ester is combined with a simple alcohol, methanol, and a catalyst, resulting in the breakup of the triglyceride ester to form glycerol and three methyl esters (biodiesel) A typical molecule of biodiesel looks like the structure below.  Mostly it is a long chain of carbon atoms, with hydrogen atoms attached, and at one end is what wecall an ester functional group .
Making good biodiesel requires several other steps besides the transesterification reaction(as shown in the right).  The first is to remove any traces of water in the vegetable oil.  If this is not done, the water will later react with the vegetable oil in the reaction and make soap.
If soap gets made, then later it complicates the steps after the transesterication reaction that are needed to separate the biodiesel from leftover methanol, the NaOH or KOH catalyst, and the glycerol byproduct.Diesel engines can burn biodiesel fuel with no modifications (except for replacing some rubber tubing that may soften with biodiesel).  This is possible because biodiesel is chemically very similar to regular diesel, shown below.  Notice that regular diesel also has the long chain of carbon and hydrogen atoms, but doesn’t have the ester group.Actually, the first diesel engines didn’t run on “diesel” fuel, but on vegetable oil, a sample molecule of which is shown below.  Notice that it also has the long rows of carbon and hydrogen atoms, but is about three times larger than normal diesel molecules.  It also has ester functional groups , like biodiesel.That larger size of vegetable oil means that in cold weather it gels, making it hard to use in an engine.  Converting it into biodiesel makes it a smaller molecule, closer to the size of regular diesel, so that it has to get colder than vegetable oil before it starts to gel.

Miracle Of Tooth Paste with chemistry

Miracle Behind The Shiny Teeth !

Toothpaste is probably the first product that everyone use in the morning as well as the last before going to bed. A smile with white and healthy teeth and gums is what everyone wants to have. Every toothpaste contains binders, abrasives, flavors, sweeteners, fluorides, tooth whiteners, a preservative, and water.
     Toothpaste, which contains sodium fluoride, belongs to the group of weak bases. The high pH of the toothpaste helps to kill the bacteria that reside in our mouth at the time of brushing. Those bacteria prefer a neutral to slightly acidic environment, exactly the conditions of our unbrushed mouth. Tooth enamel naturally loses its minerals and decays. Fluoride works with calcium and phosphate to slow this process and improve remineralization, or the production of new tooth enamel. Fluorides reduce decay by increasing the strength of teeth. Sodium fluoride is the most commonly used fluoride. Sodium perborate is used as a tooth whitening ingredient. Most toothpastes contain the preservative p-hydrozybenzoate. Water is also used for dilution purposes. Fluoride has also been added to other dental products like mouthwash and the fluoride varnish used by dentists.      So, brushing your teeth twice in a day is very important as it keeps your teeth clean and shiny like this,



Secret of Scent(Perfumes)

Secret Behind The Wonderful Scent World!!!
   Nowadays, perfumes are commonly and widely being used in daily life by everyone. Perfume has been used for century to cover the body odor.

   Perfumes encompass a wide variety of chemicals (called notes), which are tailored for specific occasions and seasons. In fact, most of the perfumes are engineered to have three-part of structure.
1)Top notes: light scent that fade quickly
2)heart notes: scent last for several hours
3)Base notes: Scent stick stubbornly to the skin
  A perfume basically consists of 78-95% of ethyl alcohol, and the rest are essential oils. Staying power of the perfume is highly depend by the rate of evaporation.

  Many methods are used to synthesis the perfume.
A) Maceration
1) Raw ingredients are soaked in the solvent.
2) The fragrances are drawn out and collected.

B) Expression
1) Raw ingredients are being compressed.
2) The aromatic oils are being squeezed out.


   By using perfume, our will smell amazingly unique, provides ultimate expression of individuality and causing others to take notice of ours unique style and grace. 

Cosmetics Secret

Secret of beauty J
  Cosmetics (colloquially known as makeup or make-up) are care substances used to enhance the appearance or odor of the human body. They are generally mixtures of chemical compounds, some being derived from natural sources, many being synthetic.
   In the U.S., the Food and Drug Administration (FDA) which regulates cosmetics, defines cosmetics as "intended to be applied to the human body for cleansing, beautifying, promoting attractiveness, or altering the appearance without affecting the body's structure or functions." This broad definition includes, as well, any material intended for use as a component of a cosmetic product. The FDA specifically excludes soap from this category.
 
   During the 20th century, the popularity of cosmetics increased rapidly. Cosmetics are increasingly used by girls at a young age, especially in the United States. Due to the fast-decreasing age of make-up users, many companies, from high-street brands like Rimmel to higher-end products like Estee Lauder, have catered to this expanding market by introducing more flavoured lipsticks and glosses, cosmetics packaged in glittery, sparkly packaging and marketing and advertising using young models. The social consequences of younger and younger beautification  had much attention in the media over the last few years.
    Criticism of cosmetics has come from a variety of sources including some feminists, religious groups, animal rights activists, authors and public interest groups. Growing awareness and preference for cosmetics exists for cosmetics lacking toxic ingredients, especially those derived from petroleum,sodium lauryl sulfate (SLS), and parabens.

Beauty can make happy J
Cosmetics are regarded as a means of enhancing one's complexion and beautifying the skin. For examples,
·        Skin creams and lotions can be used to deep-cleanse the skin.
·        If pores in the skin are blocked, it may lead to infection and acne formation. Various cosmetic cleansing products thoroughly cleanse the skin and remove the dirt and microorganisms from the skin.
·        After cleansing, moisturizers are applied to prevent drying of the skin and to keep it smooth and radiant. Moisturizers also offer excellent protection against cold winds and act as a lubricating agent.
·       There are special sun-protection creams/lotions that can protect you from the harmful UV rays of the sun. These creams minimize the risk of skin cancer, which is the result of exposure to sun rays.
·        Many cosmetics contain vitamins such as A, D, E and K. These vitamins are essential for healthy skin and hair.
·       To cope with body odor, one can use deodorants and perfumes. These help in making one feel fresh all through the day.
·       Apart from skin care, there are also varieties of shampoos and conditioners available, which keep the hair clean, soft and healthy.

Besides that, cosmetics are used not only for skin care, but also to treat certain skin problems. Dark spots or pimples on the face can be hidden using cosmetic products like concealers. You can enhance your most attractive facial features using makeup. Moreover, you can also cover dark circles and wrinkles using various anti-aging creams and eye makeup. Apart from that, not only your face, you can also decorate your nails using attractive nail colours. The wide range of hair colours available today also helps you to modify and highlight your hair in the colour and shade of your choice.
Sometimes too much beauty is not good for health L
  Increasingly, people react to the pollution in their environment with skin diseases and allergies. Just five to ten percent of the approximately 30 million allergy sufferers in Germany react excessively to certain additives and preservatives, both in their food and in their cosmetic products.
    Over the years, numerous methods were developed that were aimed at making products more durable and less perishable. As part of this, countless synthetic additives, which were then admixed to the care products to preserve these longer. Meanwhile, many of these substances are suspected trigger allergies or even cancer can. These findings are based on long-term studies, only in the wake of the global disease spread and thus many people could be made. In spite of previous laboratory and animal experiments, it was not possible to study these long-term effects before the introduction of these substances. The result we see now: Excessive sensitivity of many people on certain products.
  In a nutshell, cosmetics can bring about a huge change in your personality. However, you need to be cautious while using the same. Before buying any cosmetic products, make sure that they are meant for your skin type lest you want to break out into an allergy. Buy products of reputed brands and you will be assured of excellent quality.

Why Can’t Soap Cleanse Our Clothes?

Why Can’t Soap Cleanse Our Clothes?

Soap is the result of the mixture of potassium salts of fatty acids which is obtained from vegetable oils or animal fats and which is reacted with an alkali such as potassium hydroxide. This process of reacting the potassium salts of fatty acids with an alkali is known as saponification.

The saponification process is mostly practiced and performed for the making of soap industrially. This process involves the process of heating animal fats or vegetable oil and reacting with an alkali in order to give the result of soap and water mixed with glycerine. The another part of the process is neutralization of fatty acids with an alkali. The fats and oils are hydrolyzed with a high-pressure steam to produce fatty acids and glycerine. After that, the fatty acids is purified by distillation and neutralization with an alkali to yield soap and water.

If the alkali is sodium hydroxide, then, the sodium soap will be formed. Sodium soaps are made in solid form. Thus, they are also known as ‘hard’soaps. In contrast, if the alkali is potassium hydroxide, then, the soap formed will be smoother and is found in liquid form. This type of soaps is usually found in liquid-hand soaps and shaving cream. The carboxyl group present at the end of the soap molecule is attracted towards the water which is hydrophilic while the other end of the soap molecule which is a hydrocarbon chain is attracted to oil and grease which are non-polar substances rejected by water molecules. This end is known as the hydrophobic end.

Although,soap is a cleaning agent, the cleaning action of soap is affected by water hardness. Soap is proved to be less efficient in cleaning when dissolved in hard water. The water is labeled as hard water due to the presence of mineral salts such as Calcium ions and Magnesium ions which contributes to the formation of the insoluble precipitate also known as scum when soap reacts with these mineral salts. The scum formed on clothes makes the fabric stiff and thus causes a visible stain to deposit on clothes. Moreover, scum attaches to the internal parts of washing machines.

The reaction of soaps with hard water decreases the amount of soap present to be used for the cleaning action. However, if soap is let to react with soft water, the soil on stains and dirts on the clothes shows the presence of mineral salts which eventually reduces the effectiveness of soap in the cleaning action. Therefore, soap is inflexible to be used for laundry purposes, especially in a variety of fibres, washing temperatures and water conditions nowadays.
 
 

Common Household Chemicals That May Be Dangerous

Air Fresheners   - Air fresheners may contain any of a number of dangerous chemicals. Formaldehyde irritates the lungs and mucous membrane...