A sample of iron ore weighing 0.2792 g was dissolved in an excess of a dilute acid solution. All the iron was first converted to Fe(II) ions. The solution then required 23.30 mL of 0.0194 M KMnO4 for oxidation to Fe(III) ions. Calculate the percent by mass of iron in the ore
Chapter 2 Monday, August 28, 2017 9:05 AM -Greeks were the first to attempt to explain why chemical changes occur -alchemy dominated for 2000 years (trying to turn cheap metals into gold) Several elements discovered Mineral acids prepared -Robert Boyle was the first chemist Performed quantitative experiments Developed first experimental definition of an element Law of conservation of mass (lavoisier) Mass is neither created nor destroyed Law of definite proportion (proust) A given compound always contains exactly the same proportion of elements by mass Law of multiple proportions (dalton) When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers Just means have whole numbers for a compound Dalton's atomic theory Each element is made up of tiny particles called atoms The atoms of a given element are identical Chemical compounds are formed when atoms of different elements combine with each other A given compound always has the same relative numbers and types of atoms Gay-lussac and avogadro Measured (under same T and P) the volumes of gases that are reacting with each other Avogadro's Equal volumes of diff gases contain same number of particles Volume determined by number, not size, of molecules 2H2 + 02 = 2H20 figured out how chemicals were existing, formulas Thomson Existence of negati
