Hydrofluoric acid solutions cannot be stored in glass containers because HF reacts readily with silica dioxide in glass to produce hexafluorosilicic acid ( H 2 Si F 6 ). Si O 2 (s) + 6HF(aq) H 2 Si F 6 (aq) + 2 H 2 O(l) 40.0 g Si O 2 and 40.0 g HF react to yield 45.8 g H 2 Si F 6 . a. What is the limiting reactant? b. What is the mass of the excess reactant? c. What is the theoretical yield of H 2 Si F 6 ? d. What is the percent yield?
Chapter 2: Atoms, Molecules, and Ions 2.1 Early Ideas in Atomic Theory Dalton’s atomic theory 1. Matter is composed of atoms—the smallest unit of an element that can participate in a chemical change. 2. Each element consists of only one type of atom with identical masses and chemical properties. 3. Atoms of one element differ in properties from atoms of other elements. 4. A given compound consists of at least 2 different elements combined in consistent whole # ratios. 5. Atoms are rearranged to yield different substances but never created nor destroyed. Law of definite proportion (constant composition) – all samples of a pure compound contain the same elements in the same proportion by mass Law of multiple proportions – when 2 elements