CHEM151Take-home Q3 Key

Chemistry (MasteringChemistry Series)

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Unformatted text preview: Take‐Home Quiz #3 (DUE Friday September 19th, 2008) Name Date Score 1) Define the Law of Conservation of Mass. Cannot create nor destroy matter 2) Define the Law of Multiple Proportions. Two or more elements can combine to form more than one compound in a specific ratio 3) Define the Law of Definite Proportions. Elements combine in specific ratios 4) The Cathode Ray Tube was used to discover ___Electrons__. 5) The Oil Drop Experiment by Millikan was used to find __The charge of an electron (1.6 x 10‐19 C)_. 6) Define the following. a. Isotope Atoms of the same element, but differ in number of neutrons b. Ion Atom with different number of protons and electrons (i.e. short an electron has an oxidation or charge of +1) 7) How many electrons, protons, and neutrons are in the following isotopes? a. 24Mg 12 protons, 12 electrons, neutrons = 24 – 12 = 12 66 b. Zn 30 protons, 30 electrons, neutrons = 66 – 30 = 36 c. d. 32 235 U 92 protons, 92 electrons, neutrons = 235 – 92 = 143 S 16 protons, 16 electrons, neutrons = 32 – 16 = 16 8) What is the mass of magnesium if 24Mg has a mass of 23.9850 amu and 78.99% abundant, 25Mg has a mass of 24.9858 and is 10.00% abundant, and 26Mg has a mass of 25.9826 amu and is 11.01% abundant? 0.7899 23.9850 amu 18.95 amu 2.499 amu 2.861 amu 0.1000 24.9858 amu 0.1101 25.9826 amu 18.95 amu 2.499 amu . . 9) Identify each of the following as a mixture or a substance. Also identify if it is an atom, element, molecule, and/or compound. A1: Molecule/Compound – Pure A2: Molecule/Compound – Pure A3: Molecule/Compound – Pure C1: Atoms/Element – Pure C2: Molecules/Compounds – Mixture C3: Atoms/Elements & Molecule (not a compound) ‐ Mixture 10) Identify each compound as ionic or covalent. a. MgCl2 ‐ Ionic b. SCl2 ‐ Covalent c. NaNO3 ‐ Ionic d. C6H14 ‐ Covalent ...
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This document was uploaded on 09/27/2011.

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