CHEM103 Lecture Notes - Lecture 1: Antoine Lavoisier, Cathode Ray Tube, Robert Andrews Millikan

statement, "In a chemical reaction, matter is neither created nor destroyed" is called A) the Law of Conservation of Mass B) the Law of Definite Proportions. C) the Scientific Method D) the Law of Multiple Proportions. E) Dalton's Atomic Theory 9) The 10) Without using a calculator, solve the following problem: 10) 1105)(1 102)]2 (1 10-10) A) 1 10-6 B) 1 1034 D) 1 × 1024 11) Round off 00507506 to four significant figures A) 5100 B) 5076 C) 0051 D) 5.075105 12) A substance that can't be chemically broken down into simpler substances is A) a compound B) an element. C) an electron D) a heterogeneous mixture. E) a homogeneous mixture. 12) 13) How many cm are in 20 2 ft? A) 616 cm B) 7.95 cm C) 51.2 cm 13) D) 0.663 cm E) 242 cm 14) What does "X" represent in the following symbol? 28 14 14) A) ruthenium B) zinc C) sulfur D) silicon E) nicke 15) Identify a cation. 15) A) an atom that has gained an electron C) an atom that has lost a proton B) an atom that has gained a neutrorn D) an atom that has lost an electron 16) Which of the following elements is a alkali metal? 16) A) Ca B) U 17) Isotopes differ in the number of 17) A) neutrons. B) electrons C) neutrons and protons D) gamma particles. E) compounds

Which of the following statements is FALSE according to Dalton's Atomic Theory? A) An atom of nitrogen can be broken down into smaller particles that will still have the unique properties of nitrogen. B) Atoms of sodium do not change into another element during chemical reaction with chlorine. C) Atoms combine in simple whole number ratios form compounds. D) All atoms of chlorine have identical properties that distinguish them from other elements. E) One carbon atom will combine with one oxygen atom to form a molecule of carbon monoxide4. In a chemical reaction, matter is neither created or destroyed. Which law does this refer to? A) Law of Definite Proportions B) Law of the Conservation of Mass C) First Law of Thermodynamics D) Law of Modern Atomic Theory E) Law of Multiple Proportions What is the mass of 0.500 mol of dichlorodifluoromethane, CCl_2 F_2? A) 121 g B) 242 g C) 4.14 times 10^-3 g D) 60.5 g How many millimoles of Ca(NO_3)_2 contain 4.78 times10^22 formula units of Ca(NO_3)_2? The molar mass of Ca(NO_3)_2 is 164.10 g/mol. A) 20.7 mmol Ca(NO_3)_2 B) 79.4 mmol Ca(NO_3)_2 C) 57.0 mmol Ca(NO_3)_2 D) 12.6 mmol Ca(NO_3)_2 E) 13.0 mmol Ca(NO_3)_2 Identify the compound with covalent bonds. A) NaCl B) Kr C) Li D) CH_4 E) KBr If the walls in a room are 955 square feet in area, and a gallon of paint covers 15 square yards, how many gallons of paint are needed for the room? (3 ft = 1 yd) A) 24 gallons B) 47 gallons C) 21 gallons D) 7.1 gallons E) 2.3 gallons Identify a solid. A) no definite shape and definite volume B) no definite shape and no definite volume C) definite volume and definite shape D) definite volume and no definite shape How many Fe atoms are contained in 787 g of Fe? A) 5.90 times 10^25 Fe atoms B) 7.09 times 10^21 Fe atoms C) 4.27 times 10^22 Fe atoms D) 4.18 times 10^24 Fe atoms E) 8.49 times 10^24 Fe atoms Barium belongs to the ______ group of the periodic table. A) alkali metal B) alkaline earth metal C) noble gas D) halogen

Science Tutor: Chemistry Name: Mixtures, Solutions, &Compounds: Chemical Equations Date Chemical Equations If a chemical symbol can be thought of as a letter and a chemical formula as a word in the language of chemistry, then a chemical equation is a statement or sentence. A chemical equation is a shorthand way of describing a chemical reaction between two or more substances. A "+ sign means "combines with." An arrow points away from the reactants and toward the products (See page 10), and an arrow means "yields." 2Na + Cl2 → 2NaCl means sodium combines with chlorine to yield sodiumn chloride (salt) Look closely at the equation above. Notice the "2" in front of NaCI on the right and Na on the left. That 2, called a coefficient, is necessary to make this equation balance. Remember Antoine Lavoisier? (Page 15) Matter is neither created nor destroyed in a chemical reaction. The same number of each kind of atom must be on both sides of a chemical equation. Because chlorine only exists as a molecule consisting of two chlorine atoms, it requires two atoms of sodium to yield two molecules of salt (NaCI). This illustrates another important law stated clearly by the French chemist Joseph-Louis Proust in 1799. Chemical compounds always combine in certain specific fixed proportions. Wherever sodium and chlorine combine, two atoms of sodium will be necessary to react with one molecule of gaseous chlorine. 1 . For the equation 2Mg + O2→ 2MgO + energy: A. List the reactant or reactants 2Hato B. List the product or products C. How many atoms of magnesium does it take to combine with one molecule of oxygen? D. How many molecules of magnesium oxide are produced in this reaction? 2. Hydrogen can combine with oxygen to produce water. We could write the equation like this: H2 + O2 → H2O. But this equation is unbalanced! Rewrite this equation with the correct coefficients so that an atom of oxygen doesn't disappear! (Be careful. If you add a coefficient to one side you may have to adjust the other. Count all the atoms.) 3. Now that you have the idea, balance the following equations: A, Pho, → PbO + 02 C. Ca + H2O → Ca(OH)2 + H2 How is following a recipe to mix up a batch of biscuits (or any other food item) similar to Proust's law for chemical reactions? 4. OMark Twain Media, Inc., Publishers 17