Significant FiguresDimensional AnalysisDensitySlide 4Slide 5Slide 6Law of Constant CompositionLaw of Multiple ProportionsLaw of Conservation of MassAtomic Theory of MatterAtomic Theory of MatterAtomic Theory of MatterThe ElectronDiscovery of the NucleusChapter 1 1Significant FiguresWhen addition or subtraction is performed, answers are rounded to the least significant decimal place.When multiplication or division is performed, answers are rounded to the number of digits that corresponds to the least number of significant figures in any of the numbers used in the calculation.Chapter 1 2Dimensional AnalysisDimensional analysis is a technique used to convert one physical quantity (or unit) to another using conversion factors.Chapter 1 3DensityDensity is the ratio of mass per unit volume of a substance:Vmd =Chapter 1 4A beaker has a mass of 85.2 g when empty and 342.4 g when it contains 325 mL of liquid methanol. What is the density of the methanol?Chapter 1 5How many kilograms of methanol does it take to fill the 15.5-gal fuel tank of an automobile modified to run on methanol? (1 gal = 3.785 L)Atoms, Molecules,and IonsChapter 2 7Law of Constant CompositionThe law of constant composition states that the elemental composition of a pure substance never varies (also known as the law of definite proportions).Chapter 2 8Law of Multiple ProportionsThe law of multiple proportions states that when two or more different compounds of the same two elements are compared, the masses of one element that combine with a fixed mass of the second element are in the ratio of small whole numbers.Chapter 2 9Law of Conservation of MassThe law of conservation of mass states that the total mass of substances present at the end of a chemical process is the same as the mass of substances present before the process took place.Chapter 2 10Atomic Theory of MatterEach element is composed of extremely small particles called atoms.All atoms of a given element are identical to one another in mass and other properties, but the atoms of one element are different from the atoms of all other elements.Chapter 2 11Atomic Theory of MatterCompounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms.Chapter 2 12Atomic Theory of MatterAtoms of an element are not changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions.The ElectronChapter 2 13Discovery of the NucleusChapter 2