Lịch sử của hóa học có thể được coi như bắt đầu từ lúc Robert Boyle tách hóa học từ khoa giả kim thuật trong tác phẩm The Skeptical Chemist (Nhà hóa học hoài nghi) vào năm 1661 nhưng thường được đánh dấu bằng ngày Antoine Lavoisier tìm ra khí ôxy vào năm 1783. | Reactions in Ionic Compounds in Water Molecular Equations Ionic Equations Net Ionic Equations Acid-Base Reactions Strong Acids and Bases Bronsted Acids and Bases Acid-Base Neutralization General Properties of Aqueous Solutions Electrolytes and Nonelectrolytes Strong Electrolytes and Weak Electrolytes Precipitation Reactions Oxidation-Reduction Reactions Oxidation Numbers Oxidation of Metals in Aqueous Solutions Balancing Simple Redox Equations Other Types of Redox Reactions Concentration of Solutions Molarity Dilution Aqueous Reactions and Chemical Analysis Gravimetric Analysis Acid-Base Titrations . . - . . 1 f . . í r- i VW -V h - Prevention of Drunk Driving Every year in the United States tens of thousands of people are killed and half a million more are injured as a result of drunk driving. In recent years most states have lowered the legal limit of blood alcohol concentration BAC from to percent. Despite stiffer penalties for drunk-driving offenses and high-profile campaigns to educate the public about the dangers of driving while intoxicated law enforcement agencies still must devote a great deal of work to removing drunk drivers from America s roads. The police often use a device called a Breathalyzer to test drivers suspected of being drunk. In one type of device the breath of a driver suspected of driving under the influence of alcohol is bubbled through an orange solution containing potassium dichromate K2Cr2O7 and sulfuric acid H2SO4 . The alcohol in the driver s breath reacts with the dichromate ion to produce acetic acid HCiH CU . which is colorless and green chromium III sulfate Cr2 SO4 2 . The degree of color change from orange to green indicates the alcohol concentration in the breath sample which is used to estimate the BAC. The basis for the Breathalyzer test is a relatively simple chemical reaction called an oxidation-reduction reaction. This is one of several important types of reactions that can occur in aqueous solution. A blood .
