CHE 140 Name__Chesi Spriggs First Hour Exam Potentially useful information 1000 g = 1 kg 1000 mL = 1 L 1 in = 2.54 cm 1 mL = 1 cm3 D = m/v Select the best choice for the following questions. ___e___ 1. A hypothesis is a(n) a. formulation of principles based on facts. b. modification of a theory. c. organized body of knowledge. d. tentative explanation of observations. e. None of the above. __b___ 2. The initial success of the Bohr theory was based
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Combustion of Acetylene (ethyne) Rx: Back Why I don’t do acetlyene explosions in our lab.... Combustion of alkanes A quick review.... • Combustion reactions of alkanes consist only of C and H (hydrocarbon) • require O2(g) as a reactant • produce CO2(g) and H2O(g) and a large amount of energy!! Oxygen can be the limiting reagent which can lead to Incomplete combustion. For complete combustion of a hydrocarbon‚ oxygen must be in excess. If there isn’t sufficient oxygen‚ incomplete combustion occurs
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In the Lewis symbol for a fluorine atom‚ there are __________ paired and __________ unpaired electrons. A) 4‚ 2 B) 0‚ 5 C) 2‚ 5 D) 6‚ 1 E) 4‚1 2. Which of the following would have to gain two electrons in order to achieve a noble gas electron configuration? O Sr Na Se Br A) Sr B) Br C) Sr‚ O‚ Se D) Na E) O‚ Se 3. The electron configuration of the S2- ion is __________. A) [Ne]3s23p2 B) [Ne]3s23p6 C) [Kr]3s22p-6 D) [Ar]3s23p2 E) [Ar]3s23p6 4. The ion NO- has __________
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1. Iron (IIII) and copper (II) sulfate solution Fill a small test tube halfway with copper (II) sulfate solution. Add a 2.0 gram iron rod to the solution and observe the reaction. 2 Fe + 3 CuSO4 = 3 Cu + Fe2(SO4)3 The new product is iron (III) sulfate‚ it contains the Fe 3+ ion which is brown. Lead (II) nitrate and potassium iodide solutions Pour about 2.0 mL of lead (II) nitrate into the test tube. Add 5 to 10 drops of potassium iodide solution to the test tube and record your observations
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Stoichiometry • Calculations involving quantities of consumed reactants and formed products based on a BALANCED chemical equation. Mass Molar Mass Mole Coeff Bal Eqn Mole Molar Mass Mass Example 2 • The Haber Process involves reacting gaseous nitrogen and gaseous hydrogen to form ammonia. Determine the mass in grams of hydrogen gas required to form 1.00 x 103 g ammonia. Your Turn 2 • If you react 52.9 g of potassium chlorate (KClO3) with excess phosphorus
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Q. 1. During the electrolysis of molten lead bromide‚ which of the following takes place : A : Bromine is released at the cathode. B: Lead is deposited at the anode. C : Bromine ions gain electrons. D: Lead is deposited at the cathode. Ans : - D. Q. 2. Here is an electrode reaction : Cu → Cu2+ + 2e-. [i.e. Cu- 2e- →Cu2+]. At which electrode(anode or cathode) would such a reaction take place. Is this an example of oxidation or reduction. Ans : - At anode. Oxidation. Q. 3. A solution contains
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Isotopes and average atomic mass Isotope: element variations with different atomic mass but same atomic number Isotopic Abundance: the relative amount in which each isotope of an element Calculating: given 2 isotopes of an element [B: 10.01u] [B: 11.01u] 1) Given average atomic mass: 10.81u If given percentages‚ you can find average atomic mass by adding each portion 2) Set variables for unknown values Let x represent % abundance for 10/5 B Let 1-x represent % abundance for 11/5 B Calculate:
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Scuba diving is a form of underwater diving in which a diver uses a scuba set to breathe underwater. According to the Professional Association of Diving Instructor (PADI)‚ a “DEEP DIVE” is considered to be anything from 18 meters (60 ft) to 30 meters (100 ft). A scuba diver moves around underwater by using swim-fins attached to the feet‚ however external propulsion can be provided by a diver propulsion vehicle. Scuba diving may be performed for a number of reasons; either for recreational purposes
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FINAL SUMMATIVE PRESENTATIONS This evaluation will involve working in groups of 3 to prepare a written report‚ poster and a demonstration of food preparation of your chosen topic. PART A: WRITTEN REPORT This should give the reader background information on your selected topic. This information will be shared with the class as an ongoing commentary in addition to your demonstration. The report will be typed using proper report format with a title page and subheadings. It should
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Introduction Commissioned by the Deltion College from the third class International Business Studies I have written this report. The report you’ll see in front of you is the work of 10 weeks research. For this unit I’ve been asked to plan the set-up of a small business in my local area. Starting a business involves planning‚ making key financial decisions and completing a series of legal activities.
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