Explain the purpose of a salt bridge in an electrochemical cell.
CH101 Sections 1.5-1.9 (scroll to next page) I. Modern Atomic Theory and Its Laws A. Law of Conservation of Mass- In a chemical reaction, matter is neither created nor destroyed. B. Law of Definite Proportions- All samples of a given compound, regardless of how they were made, have the same proportions of their constituent elements. C. Law of Multiple Proportions- When two elements A and B form two different compounds, the masses of element B that combine with 1g of element A can be expressed as a ratio of a small whole numbers. II. Discovery of Electron A. J.J. Thomson’s Cathode Rays 1. Cathode rays travel through a glass cathode ray tube away from the negative cathode towards the positive anode. 2. Discovery of a negatively charged, low mass particle present in all atoms called the electron B. Millikan’s Oil Drop Experiment 1. Calculated charge on oil droplets falling in and electric field 2. Discovered that the charge on an electron is -1.60x10^-19 C. Ernest Rutherford’s Gold Foil Experiment 1. Bombarded thin gold foil with positive particles a) Most passed through but some were deflected b) Denounced the plum pudding model that an atom is a positive sphere with negative electrons in it 2. Discovered the structure of the atom and explained it with the nuclear theory