vce chemistry units 1 & 2 horsham college an introduction to chemistry chapter 1 – vce...

VCE Chemistry Units 1 & 2 Horsham College

An Introduction to Chemistry

Chapter 1 – VCE Chemistry


An Introduction…

•Chemistry is the science of matter at the atomic to molecular scale, dealing primarily with collections of atoms, such as molecules, crystals, and metals. •Thousands of years ago, people observed natural materials to see how they can be used. •These people were known as alchemists (The word ‘chemistry’ is Greek for alchemy).

Alchemists


Alchemy• Alchemy was the earliest form of chemistry

(Alchemy is a protoscience). • Alchemy refers to both an early form of the

investigation of nature and an early philosophical and spiritual discipline, both combining elements of chemistry, metallurgy, physics, medicine, astrology, semiotics, mysticism, spiritualism, and art.

• Alchemy was practiced in Mesopotamia, Ancient Egypt, Persia, India, and China, in Classical Greece and Rome, in Muslim civilization, and then in Europe up to the 19th century—in a complex network of schools and philosophical systems spanning at least 2500 years.

• The roots of chemistry can be traced to the phenomenon of burning. Fire was a mystical force that transformed one substance into another and thus was of primary interest to mankind. It was fire that led to the discovery of iron and glass.


Goals of AlchemyGoals of alchemy

1. The transmutation of metals Gold was seen as the perfect material. Transforming othermaterials into gold was a high priority.

2. The creation of an elixir that would prolong life indefinitely Alchemists also tried to discover the secret of immortality.

3. The transmutation of human life (illegal) 4. To search for the Philosophers Stone

The philosopher’s stone was a theoretical magical substance that

could manipulate time ie. Speeding up or slowing down natural reactions. Alchemists hoped that this could slow down the aging process.Alchemists worked within sacred places in respect of mother

earth. However, the field of alchemy was also filled with unscrupulous people who cheated people with false claims.


Alchemists of China•Chinese alchemy began 3000 years ago•The alchemists strived to create the ‘pill of immortality’.•Chinese alchemists strived to refine and perfect themselves rather than change metals into gold. •Black powder was an important invention by Chinese alchemists.•Chinese alchemy was closely connected to Taoist forms of traditional Chinese medicine, such as Acupuncture and to martial arts such as Tai Chi Chuan and Kung Fu.


Alchemists of India and Tibet

•Indian and Tibetan alchemy strived to support medicine which increases longevity of people.•They were interested in finding an elixir of immortality called the ‘jewel of the wise’.•They used mercury to reduce substances to their primary form.•Tibetan alchemists used a mixture of metals as an elixir.•Some common laboratory techniques were used such as; distillation, sublimation, powdering and melting in preparing their elixirs.


Alchemists of Egypt•Egyptian alchemists created fine perfumes, medicines, cosmetics, dyes and jewellery.•They used mercury to separate metal ores•They used chemicals in the mummification process.•Alexandria became an intellectual centre•They combined theoretical knowledge with experimental work.•However, the Romans destroyed much of the work completed by these alchemists during their persecution.


Alchemy and Western Science• Alchemy moved to Greece and Rome

after the loss of records at Alexandria. It then flowed to the Middle East after the fall of the Roman empire.

• A famous alchemist of the Islamic world, Jabir ibn Hayyan, believed that all metals are made up of four elements; Earth, wind, fire and water.

• By altering the balance of these four elements, he believed that he could form different metals.

• Jabir carefully measured and weighed different substances. This scientific approach later influenced European alchemy.

• Alchemy then spread to Spain and the rest of Europe.

• Alchemy was excepted by Christian beliefs in Europe.

• Secret signs and symbols were used by alchemists

Jabir ibn Hayyan


Questions 1.1

• Complete questions 1-6 on P. 8 of Nelson VCE Chemistry.


The Elements•Greek philosophers, such as Empedocles, believed that all matter was made from just four ingredients – earth, air, water and fire. These were called elements. Aristotle also believed a five element, called aether existed. Aether is a divine substance that heavenly bodies are made of.•Chinese philosophers believed of five elements (See below).•Today, there are 111 elements shown on the periodic table.

The 5 elements


The Development of Alchemy and Chemistry


The Origins of Atomic Theory

•Greek philosopher Leucippus suggested that all matter is made up of small particles.•His student, Democritus expanded on Leucippus’ idea calling the particles atomos, meaning that which can’t be divided.•However Aristotle strongly believed the element theory, which was widely accepted throughout Europe during the dark ages.

Democritus


Scientific Method•In the 17th century scientists began working scientifically – ie. they saw the need to back up theories with experimental evidence.•Many new instruments were invented which vastly improved scientific studies.


Sceptical Chemists• Scientists such as Robert Doyle began questioning

Aristotle’s element theory.• Scientists such as Sir Isaac Newton questioned

the idea that matter was continuous. Leucippus suggested that matter was held together by mutual attraction.

• The extraction of elements such as oxygen and hydrogen led the way for a redefining of the term element.

• Today the elements are shown on the periodic table.


The Lavoisiers•Antoine Lavoisier wrote the first ‘modern’ textbook called Elements of Chemistry.•He was assisted by his wife Marie.•The Lavoisier’s discovered the laws of mass conservation and constant proportions.•Antoine was beheaded during the French revolution. •Marie published their work some time after.


Lavoisier’s Chemical Laws

The law of conservation of mass states that the mass of a closed system of substances will remain constant, regardless of the processes acting inside the system. An equivalent statement is that matter changes form, but cannot be created nor destroyed.

The law of constant proportions states that the same compound, however formed, contains the same elements chemically combined in constant proportions by weight.


Classifying Matter


Elements, Compounds and Mixtures

• Element – A chemical element is a substance that cannot be decomposed or transformed into other chemical substances by ordinary chemical processes.

• Compound - A chemical compound is a chemical substance consisting of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition.

• Mixture - In chemistry, a mixture is the product of a mechanical blending or mixing of chemical substances like elements and compounds, without chemical bonding or other chemical change, so that each ingredient substance retains its own chemical properties and makeup.


John Dalton’s Model of the Atom

•John Dalton designed experiments to see why elements combine in constant proportions.•He deduced that elements have unique set of atoms that rearrange when combined with other elements.•Dalton believed that an atom is a solid sphere. This model has changed many times since then.


Dalton’s Atomic TheoryFive main points of Dalton's Atomic Theory•Elements are made of tiny particles called atoms •All atoms of a given element are identical •The atoms of a given element are different from those of any other element •Atoms of one element can combine with atoms of other elements to form compounds. A given compound always has the same relative numbers of types of atoms. •Atoms cannot be created, divided into smaller particles, nor destroyed in the chemical process. A chemical reaction simply changes the way atoms are grouped together.


Questions 1.2



Review Questions


vce chemistry units 1 & 2 horsham college an introduction to chemistry chapter 1 – vce...

Documents

chinese alchemists

alchemistsvce chemistry

elements of chemistry

word chemistry

roots of chemistry

tibetan alchemists

tibetan alchemy

field of alchemy