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11 Cards in this Set
- Front
- Back
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What is a chemical formula?
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1) A chemical formula displays the symbols for the elements making up a compound with numerical subscripts that state the relative number of atoms of each kind. For example the chemical formula P₅S₇ indicates a compound containg four atoms pf P (Phosphorus) for every seven atoms of S (Sulfur). 2) A representation of the chemical composition of a substance; refers to either the empirical formula or the molecular formula. 3) A collection of chemical symbols and subscripts that shows the composition of a substance.
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What are simplest or empirical formulas?
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1) They indicate only the identity and relative numbers of the participating atoms. 2) A chemical formula of a compound ( a substance containing two or more elements) that expresses the relative chemical amounts of its elements in terms of the smallest integer. 3) A chemical formula that shows the relative numbers of atoms of each element in a compound by using the simplest whole number subscripts.
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What is a compound?
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1) a substance containing two or more elements. 2) A specific combination of elements that can be separated by chemical techniques but not physical techniques. 3) A substance consisting of atoms of two or more elements in a definite, unchangeable ratio.
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What is the Law of Combining Volumes?
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When two gases react, the volumes that combine (at the same temperature and pressure) stand in a ratio of small whole numbers. The ratio of the volume of each product gas to the volume of either reacting gas is also a ratio of small whole numbers.
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By whom and when was the law of combining volumes discovered?
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By the French Chemist Joseph Gay-Lussac in 1808.
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Who used Joseph Gay-Lussac's "Law of Combining Volumes" in 1811?
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Italian chemist Amedeo Avogadro [ah-vuh-gah-droh; It. ah-vaw-gah-draw].
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What did Amedeo Avogadro use the Law of Combining Volume for?
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To formulate Avogadro's Law.
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What is Avogadro's Law?
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Equal volumes of different gases, held at the same temperature and pressure, contain equal number of particles.
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Are Avogadro's particles of gaseous elements the same as Dalton's atoms from his atomic theory of matter?
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Avogadro took the point of view that they were not. He proposed instead that gaseous elements (such as hydrogen, oxygen, or nitrogen) exist in diatomic( having two atoms in a molecule) molecules.
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What is a molecule?
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A grouping of two or more atoms bound closely together by strong attractive forces that maintain them in a persistent combination.
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When did Avogadro's hypothesis or law receive widespread acceptance
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In the 1860's after Stanislao Cannizzaro published his experiments that studied the elemental analyses of a large number of gaseous compounds and showed that the whole set of their chemical formulas could be established in a consistent manner that used Avogadro's hypothesis or Law.
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