AP Chemistry 1.3 Elemental Composition of Pure Substances & 1.4 Composition of Mixtures

This is a video about AP 1.3 & 1.4 TOPIC 1.3 Elemental Composition of Pure Substances LEARNING OBJECTIVE SPQ-2.A Explain the quantitative relationship between the elemental composition by mass and the empirical formula of a pure substance. SPQ-2.A.1 Some pure substances are composed of individual molecules, while others consist of atoms or ions held together in fixed proportions as described by a formula unit. SPQ-2.A.2 According to the law of definite proportions, the ratio of the masses of the constituent elements in any pure sample of that compound is always the same. SPQ-2.A.3 The chemical formula that lists the lowest whole number ratio of atoms of the elements in a compound is the empirical formula. TOPIC 1.4 Composition of Mixtures LEARNING OBJECTIVE SPQ-2.B Explain the quantitative relationship between the elemental composition by mass and the composition of substances in a mixture. SPQ-2.B.1 While pure substances contain molecules or formula units of a single type, mixtures contain molecules or formula units of two or more types, whose relative proportions vary. SPQ-2.B.2 Elemental analysis can be used to determine the relative numbers of atoms in a substance and to determine its purity. ANSWER : A (FOR MULTIPLE CHOICE)