You mix solid hydrated barium hydroxide, Ba(OH)2 ? 8H2O(s), and solid ammonium nitrate, 2NH4NO3(s), in a beaker. Th e reaction is shown here. A small pool of water in contact with the outside of the beaker freezes. Ba(OH)2 ? 8H2O(s) 1 2NH4NO3(s) 2NH3( g) 1 10H2O(l) 1 Ba(NO3)2(aq) a. List all the substances that are part of the system. b. List at least four objects that are part of the surroundings. c. Which is at a lower temperature: NH4NO3(s) or Ba(NO3)2(aq)? Explain your thinking. d. What will you feel if you touch the beaker? e. Is the reaction endothermic or exothermic? Explain your thinking. f. What evidence do you have that heat is transferred from the surroundings to the products of the reaction?
Chemistry 1211: Agarwal Chapter 1 Book Notes 1 What is Chemistry 1.1The Scale of Chemistry Chemistry: the study of matter, its transformations, and how it behaves Matter: any physical substance that occupies space and has mass o Matter consists of atoms, molecules o Most chemical transformations take place at the atomic, molecular level Macroscopic scale: matter that can be seen with the naked eye Atomic scale: (also called nano, molecular scale) used when describing individual atoms or molecules o Observations are made on the macroscopic scale o Descriptions and explanations of chemical processes are made on the atomic level o Macroscopic scale observations explain atomic scale properties 1.2Measuring Matter o Being sure to make prec