U.S. National Chemistry Olympiad: 1988 National TestGo to answers 1. A verbal statement or a mathematical equation that summarizes a broad variety of observations and experience is called a(n) (A) hypothesis (B) law (C) theory (D) evolution 2. The term that is related to the reproducibility or repeatability of a measurement is: 3. A sample of carbon dioxide that undergoes a transformation from solid to liquid to gas would undergo 4. A solution is a(n) 5. Dalton's theory of atoms consisted of all of the following postulates except (A) elements are composed of indivisible particles called atoms. (B) atoms of different elements have different properties. (C) atoms combine in fixed ratios of whole numbers. (D) the volumes of gases consumed and produced are in ratios of small whole numbers. 6. Cathode rays are
7. There are two stable isotopes of carbon. They differ with respect to 8. One 40Ca2+ion contains 9. The average atomic weight of elemental copper is reported as 63.5. Copper consists of two stable isotopes, 63Cu and 65Cu. Approximately what percent of naturally occurring copper is the 63Cu isotope? (A) 30 (B) 50 (C) 70 (D) 90 10. The best molecular formula for sulfur in its naturally occurring state is 11. The correct formula for iron(III) sulfide is 12. What is the percentage by weight of potassium in the compound KNO 3 ?
13. If 18.5 moles of the liquid compound C2Cl4are required for a particular chemical reaction, what volume should be taken? The density of C2Cl4is 1.63 g/ml. (A) 11.3 mL (B) 30.2 mL (C) 1.88 L (D) 5.01 L 14. The principle of DuLong and Petit states that the product of the atomic weight of a solid element and its specific heat, measured at room temperature, is approximately 6.2 calories per mole per degree (25.9 Joules per mole per degree). A prospector has asked you to identify the most abundant element in a mineral sample he has found. You chemically separate the most abundant element and determine that its specific heat is 5.24 x 10¯2cal per gram per degree. The element most likely is
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