Chem 209 Ch. 2 notes - Chem 209 Ch. 2 notes 2-1 - In 1774,...

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Chem 209 Ch. 2 notes 2-1 - In 1774, Antione Lavosier performed an experiment in which he heated a glass containing tin and air. The mass before heating and after heating were the same. - This led him to postulate the law of conservation of mass. It states that the total mass of the substances present after a chemical reaction is the same as the total mass of substances before the reaction. Simply put, matter is neither created nor destroyed. - Joesph Proust came up with the law of constant composition: all samples of a compound have the same composition- the same proportions by mass of the constituent elements -Dalton’s atomic theory states: 1) Each element has atoms. Atoms can neither be created nor destroyed during chemical change. 2) All atoms of the same element are identical. Atoms of different elements are not. 3) In each compound, different elements combine in a simple numeric ratio. -Dalton’s theory explains the conservation of mass (statement 1) and the law of constant composition (statements 2 and 3) -Dalton’s theory led to the law of multiple proportions: If two elements form more than a single compound, the masses of one element combined with the fixed mass of the second are in the ratio of small whole numbers. 2-2 -Pos. charges repel pos. -Pos. charges attract neg. - Rubbing causes equal amounts of positive and negative charges to appear on different objects - When charges are move perpendicular to magnets, they are deflected. Pos. charges are deflected in the direction of the force. Neg. are deflected against the force. -Cathode rays: a voltage source creates a negative charge on cathode and a positive charge on the anode. They are separated, with an empty container linking them. Cathode rays, which are a form of radiation, pass from the cathode to the anode. Cathode rays
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Chem 209 Ch. 2 notes - Chem 209 Ch. 2 notes 2-1 - In 1774,...

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