《大学化学》课程PPT教学课件（英文版讲稿）Chapter 03 Discovering the atom and subatomic particles（History of modern chemistry）

Chapter 3 Discovering the atom and subatomic particles (History of modern chemistry)

Chapter 3 Discovering the atom and subatomic particles (History of modern chemistry)

3. 1 Chemistry developed out of interest in materials The ability to control fire allowed ancient people to prepare copper(7000 years ago)and iron (3200 years ago) for tools and Weapons 商代青铜器(铜锡合金)

3.1 Chemistry developed out of interest in materials The ability to control fire allowed ancient people to prepare copper (7000 years ago) and iron (3200 years ago) for tools and weapons. 商代青铜器(铜锡合金)

火 热 空气 土 湿 水 Aristotle 四原说示意图 384-322B.C Aristotle described the composition and behavior of matter in terms of four qualities: hot, cold, moist and dry. A material is possible to be transformed to another material by changing the relative proportion of these four qualities. Gold can be made from other metals(alchemy)

Aristotle described the composition and behavior of matter in terms of four qualities: hot, cold, moist, and dry. A material is possible to be transformed to another material by changing the relative proportion of these four qualities. Gold can be made from other metals (Alchemy). Aristotle 384 - 322 B.C. 热 干 冷 湿 火 空气 水 土 四原说示意图

Democritus started thinking about atom(not cut or that which is indivisible) Tiny, hard, uncuttable Fire Atoms of tre sphere DEMOCRITUS'S MODEL

Democritus started thinking about “atom” (not cut or that which is indivisible)

Antoine Laurent lavoisier Chimiste francais(Paris, 1743-Id 1794) Father of modern chemistry unfortunate association with a company organized to collect taxes for King louis adied at guillotine of no use to the new republic of france headless body buried in unmarked grave Showed conservation of mass in chemical reactions invented precise scale to weigh small amounts of matter accurate to 0.0005 grams, about 1/100 of a drop of water mass of all reactants=mass of all products -cannot create matter from nothing, can only change form matter is not created from nothing, only changes form during chemical reactions

Father of modern chemistry ▪unfortunate association with a company organized to collect taxes for King Louis ▪died at guillotine of no use to the New Republic of France ▪headless body buried in unmarked grave Showed conservation of mass in chemical reactions ▪invented precise scale to weigh small amounts of matter accurate to 0.0005 grams, about 1/100 of a drop of water ▪mass of all reactants = mass of all products ▪cannot create matter from nothing, can only change form ▪matter is not created from nothing, only changes form during chemical reactions

Mass is conserved in a chemical reaction o OO oo &8 °oobb Atom mest x Atoms of Compound of element Y elements x and Y 16Ⅹ 8Y 8 XY Law of mass conservation(质量守恒定律): There is no detectable change in the total mass of materials when they react chemically to form new materials

Mass is conserved in a chemical reaction Law of mass conservation (质量守恒定律): There is no detectable change in the total mass of materials when they react chemically to form new materials 16 X + 8 Y 8 X2Y

Joseph Priestley found oxygen and Lavoisier named it. which means "acid former Priestley, Joseph(1733-1804) Philosopher, scientist and unorthodox theologian, Joseph Priestley is perhaps best known for his discovery of oxygen while performing experiments with gases in 1774 Ultimately, Priestley identified nine distinct gases, including carbon dioxide and nitrous oxide. He is credited with developing a sound method for infusing carbon dioxide into water, thus establishing himself as the father of carbonation

Joseph Priestley found oxygen and Lavoisier named it, which means “acid former” Priestley, Joseph (1733-1804) Philosopher, scientist and unorthodox theologian , Joseph Priestley is perhaps best known for his discovery of oxygen while performing experiments with gases in 1774. Ultimately, Priestley identified nine distinct gases, including carbon dioxide and nitrous oxide. He is credited with developing a sound method for infusing carbon dioxide into water, thus establishing himself as the father of carbonation

The Phlogiston Theory EARTH (Phlogiston Poor) MEtAL (Phlogiston Rich FIRE(Phlogiston) Chemistry was so underdeveloped at the time lavoisier gained interest in it that it could hardly be called a science. The prevailing view of combustion was the Phlogiston Theory which involved a weightless or nearly weightless substance known as phlogiston Metals and fire were considered to be rich in phlogiston and earth was considered oxygen poor

The Phlogiston Theory Chemistry was so underdeveloped at the time Lavoisier gained interest in it that it could hardly be called a science. The prevailing view of combustion was the Phlogiston Theory which involved a weightless or nearly weightless substance known as phlogiston. Metals and fire were considered to be rich in phlogiston and earth was considered oxygen poor

普利斯特里( Joseph Priestly),英 氧气的发现者国 舍勒( Carl wilhelm scheele),瑞典 Antoine Lavoisier),法国 freed thinking from phlogiston theory PRIESTLY'S DEPHLOGISTICATED AIR Red mercury calx is heated and the effluent collected over water The gas supports combustion better than air. 2HgO-△2Hg+O,个 from air, inc- rizes he has removed the phlogiston Preistly the hlogiston and support combustion Experiment is QUALITA 2KNO-A>2KNO2+O,个 LAVIOSIER'S OXYGEN Mercury is heated until a red calx forms. The volume of air in the cylinder decreases as the water rises. When calx stops forming heating is stopped Mercury plus calx has gained exactly the same weight as the cylinder has lost 2Hg+O2-2HgO Remaining air does not support combustion Calx is now heated as in P experiment. Air given off weighed the same as hGo 2Hg+O the weight lost previously and supported combustion Experiment is QUANTITATIVE

氧气的发现者 • 普利斯特里(Joseph Priestly) ，英 国 • 舍勒(Carl Wilhelm Scheele)，瑞典 • 拉瓦锡(Antoine Lavoisier)，法国 2 2 2 HgO Hg O ⎯⎯→ +   3 2 2 2 2 KNO KNO O ⎯⎯→ +   2 2 2 2 2 2 Hg O HgO HgO Hg O   + ⎯⎯→ ⎯⎯→ + 

Proust proposed the law of definite Proportions Henry Cavendish isolated hy ydrogen and Lavoisier named it meaning water former' Lavoisier also realized that water is not an element, but a compound Joseph Proust found that hydrogen and oxygen always react in a particular mass ratio and proposed the Law of Definite Proportions: Elements combine in definite mass proportions to form compounds

Henry Cavendish isolated hydrogen and Lavoisier named it meaning “water former”. Lavoisier also realized that water is not an element, but a compound. Joseph Proust found that hydrogen and oxygen always react in a particular mass ratio and proposed the Law of Definite Proportions: Elements combine in definite mass proportions to form compounds. Proust proposed the Law of Definite Proportions