Category Chemistry

What are basic phases of matter?

SOLIDS, LIQUIDS AND GASES

Chemicals may be solids, liquids or gases. Water is a liquid. When water is cooled to below 0°C it freezes and forms ice, a solid. When it is heated to 100°C it boils and changes to steam, a gas. We say that water can change its ‘state’.

A chemical’s state depends on its temperature. Solids may turn to liquids and gases and then back to solids again, as the temperature rises and falls. We usually see metals and rocks in their solid state. When they’re heated, they become softer. If they’re heated to a high enough temperature, they melt and become liquid.

Ice

Because the molecules in a solid, such as ice, are held firmly together and can only move about a fixed point, they have a definite shape.

Water

As a liquid, water molecules can move around more freely. The ‘shape’ of the water depends on the container.

Water vapour

The molecules in steam can move freely in all directions, spreading further and further apart until they fill their container.

In the Arctic, the temperature is so cold that sea water freezes into huge solid glaciers.

Steam is given off by cooling towers. The water vapour molecules move freely and spread apart.

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What is Chemical World?

Everything that exists — from the Sun in the sky to the centre of the Earth, and from animals to vegetables —is made up of chemicals. Many of these are familiar to us, such as water, salt, sugar, iron and oxygen. Chemicals can be different from each other in many ways. They have different tastes, like sugar and salt, or different appearances, like gold and silver. Chemicals come in many different forms; some are solids, others are liquids or gases.

Our world is composed of thousands of different substances. We call these substances ‘chemicals’. Chemicals make up the air we breathe, the ground we walk on and the food we eat. Even our bodies are a collection of chemicals!

Chemicals are often put into groups. Water, salt, sugar and oxygen are all chemicals. We call them ‘natural’ chemicals. Plastics, detergents and cosmetics are everyday chemicals too. But these do not occur naturally — they are ‘man-made’. Both types of chemicals are useful. Man-made cleaning agents remove dirt from our clothes and natural dyes from plants are used to colour fabrics.

Our food contains many different chemicals such as vitamins, proteins, fats, carbohydrates and sugars. Chemicals give fruit and vegetables their colour.

Water is made of chemicals and without it there would be no life on Earth.

Wool and cotton can be dyed with man-made chemicals or with natural chemicals from plants.

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What are chemicals?

There are about 100 special chemicals called ‘elements’. There are substances that cannot be broken down into simpler chemicals. The gases oxygen and hydrogen are both elements, so are iron and gold. Every element is made up of tiny particles called ‘atoms’, which are much too small to see, even with a microscope. Oxygen is composed of oxygen atoms; iron is made up of iron atoms.

Atoms can join together to make ‘molecules’. A molecule of an element is formed from only one type of atom. For example, oxygen exists as a molecule of two oxygen atoms joined together.

Combining chemicals

When two different elements combine, they often make a compound which is very different from either of them. The element sodium is a shiny metal. The element chlorine is a green and poisonous gas. Sodium atoms and chlorine atoms can combine to make a very familiar compound — salt! However, we do not make the salt we eat by combining sodium and chlorine. The salt produced from sea water. In cooler countries, salt is mined from underground.

The atoms of one element may join up with the atoms of another element. When this happens, a completely different chemical is formed. For example, when two hydrogen atoms join with an oxygen atom, they make a molecule of water. Chemicals that are made by combining two or more elements are known as ‘compounds’. Water is a compound. Sugar, salt, plastics — in fact, most of the chemicals around us — are compounds. A compound usually has different characteristics to the elements from which it is made.

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WHAT IS MADE FROM STEEL?

A huge range of items can be made from steel, from tiny paperclips to huge girders forming the frames for skyscrapers. One useful property of steel is that it can be recycled and used over and over again.

Steel has a long history. People in India and Sri Lanka were making small amounts of steel more than 2,500 years ago. It was very expensive and was often used to make swords and knives. In the middle Ages, steel could be made only in small amounts since the processes took a long time.

In the time since, there have been many changes to the way steel is made. In about the year 1610 steel started to be made in England, and the way it was made got better and cheaper over the next 100 years. Cheap steel helped start the Industrial Revolution in England and in Europe. The first industrial Converter (metallurgy) for making cheap steel was the Bessemer converter, followed by Siemens-Martin open-hearth process.

Today the most common way of making steel is the basic-oxygen process. The converter is a large turnip-shaped vessel. Liquid raw iron called “pig iron” is poured in and some scrap metal is added in to balance the heat. Oxygen is then blown into the iron. The oxygen burns off the extra carbon and other impurities. Then enough carbon is added to make the carbon contents as wanted. The liquid steel is then poured. It can be either cast into molds or rolled into sheets, slabs, beams and other so-called “long products”, such as railway tracks. Some special steels are made in electric arc furnaces.

Steel is most often made by machines in huge buildings called steel mills. It is a very cheap metal and is used to make many things. Steel is used in making buildings and bridges, and all kinds of machines. Almost all ships and cars are today made from steel. When a steel object is old, or it is broken beyond repair, it is called scrap. It can be melted down and re-shaped into a new object. Steel is recyclable material; that is, the same steel can be used and re-used.

Alloys of steel, in which steel is combined with other metals, can be very useful. Railway tracks are often made of an alloy of steel and manganese.

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WHAT IS STEEL?

Steel is an alloy of iron and carbon. Iron extracted from iron ore contains about 4% carbon and some other impurities. The carbon makes it hard but weakens it. Removing some of the carbon and other impurities in an oxygen furnace produces steel.

Steel is an alloy of iron and carbon containing less than 2% carbon and 1% manganese and small amounts of silicon, phosphorus, sulphur and oxygen. Steel is the world’s most important engineering and construction material. It is used in every aspect of our lives; in cars and construction products, refrigerators and washing machines, cargo ships and surgical scalpels.

Steels are a large family of metals. All of them are alloys in which iron is mixed with carbon and other elements. Steels are described as mild, medium- or high-carbon steels according to the percentage of carbon they contain, although this is never greater than about 1.5%.

The properties of steel are closely linked to its composition. For example, there is a big difference in hardness between the steel in a drinks can and the steel that is used to make a pair of scissors. The metal in the scissors contains nearly twenty times as much carbon and is many times harder. Notice how the percentage of carbon in the steel items in varies. Changing the carbon content changes the properties of the steel and the way that it is used.

The heat treatment given to steel can affect its properties too. Cooling a red-hot tool steel rapidly in cold water makes it harder and more brittle. We could have made the same piece of metal softer by keeping it at red heat for longer and then cooling it slowly. Heat treatment is another method that the steelmaker uses to make the properties of the steel match the job it has to do.

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WHERE IS THE BIGGEST IRON MOLECULE IN THE WORLD?

So important was the metal-working industry of Belgium that a building in Brussels called the Atomium was made in the shape of a molecule of iron — magnified 165 billion times!

Andre Waterkeyn was born 1917 in Wimbledon, London and died in Brussels in 2005 at the age of 88. In a moment of quite delightful synchronicity Double Stone Steel are building a new stainless steel colouring factory in Wimbledon.

In 1954 Waterkeyn whilst working for Fabrimetal a group of metal fabrication companies, was asked to design a building that would showcase Belgian engineering skills to the world. An iron crystal magnified 165 billion times was deemed the way to go.

Three industrial groups – the Federation of the metalworking, mechanical and electrotechnical engineering industries, the Belgian blast-furnace and steel working group and the Union on non-ferrous metals industries – joined together in a non-profit-making organisation and appointed André Waterkeyn as Managing Director.

The Atomium was a monumental image of the then new and exciting nuclear age. During the fair, the Atomium held an exhibition showing the benefits of nuclear science to mankind. This was the age where the boffins around the world were convinced that nuclear science would completely remove the need for anyone work or for any other type of power generation system. Electricity would be so cheap that it would be free to all. The world would find its Utopia at long last. The Nuclear age was going to be, safe, cheap and simple. Nuclear power would save the world. I am not sure the general public were convinced as the memory of the nuclear booming in Japan were very fresh.

The Atomium consists of nine spheres, each sphere having a diameter of 18m.The spheres are connected by twenty, 23m long metal tubes, the tubes have a diameter 3.3m. The tubes allow the visitor to move between the spheres using escalators or staircases. The structure stands on three pillars known as ‘bipods’. In 1958 the Atomium had the fastest lift in Europe, reaching speeds of 5 meters per second.

The original construction of the frame was in steel, with 10-12mm aluminium panels. The spheres’ aluminium is an alloy called ‘Peraluman 15’ which was then covered with a thin sheet of aluminium called ‘reflectal’, which was then highly polished. In 2004 the building was shut to the public to be refurbished. The original aluminium panels being replaced by polished stainless steel panels. Over 6000 honeycombed panels were fabricated in 1.2mm, grade 316L with a rock wool insulation core and a 1mm galvanised interior skin. The building looks wonderful and should stand for many many years.

“The story of the Atomium is, above all, one of love, the love that the Belgians have for an extraordinary structure symbolising a frame of mind that wittily combines aesthetic daring with technical mastery. The appearance of the Atomium is unusual and unforgettable. It has a rare quality of lifting everyone’s spirits and firing their imagination.”

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