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12 Cards in this Set
- Front
- Back
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State the 3 laws that support the existence of atoms.
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1) law of definite proportions
2) law of conservation of mass 3) law of multiple proportions |
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Experimental results supporting the existence of atoms indicated that?
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All chemical compounds share certain characteristics.
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compound
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a pure substance composed of atoms of two or more elements that are chemically combined.
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law of definite proportions
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a chemical compound always contains the same elements in exactly the same proportions by weight or mass
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law of conservation of mass
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mass cannot be created or destroyed in ordinary chemical and physical changes
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law of multiple proportions
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when two elements combine to form two or more compounds, the mass of one element that combines with a given mass of the other is in the ratio of small whole numbers
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Dalton's Atomic Theory
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1) All matter is composed of extremely small particles called ATOMS, which cannot be subdivided, created, or destroyed.
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Dalton's Atomic Theory (2)
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2) Atoms of a given element are identical in their physical and chemical properties.
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Dalton's Atomic Theory (3)
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3) Atoms of different elements differ in their physical and chemical properties.
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Dalton's Atomic Theory (4)
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Atoms of different elements combine in simple, whole-number ratios to form compounds.
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Dalton's Atomic Theory (5)
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5) In chemical reactions, atoms are combined, separated, or rearranged, but never created, destroyed, or changed.
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Dalton versus what we know today
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1) Data gathered since Dalton's time shows that the first two principles are not true in all cases.
2) Scientists can now: divide an atom into even smaller particles, destroy atoms, and create atoms. 3) Dalton didn't know that many atoms will combine with like atoms (O2). |
