Directions: The following questions involve more practice with radioactive decay half-life. Complete the problems to the best of your ability. This assignment is due by next WEDNESDAY‚ November 16th. 1. If 100.0 g of carbon-14 decays until only 25.0 g of carbon is left after 11 460 y‚ what is the half-life of carbon-14? a. Calculate how many half-lives have passed during the decay of the 100.0 g sample. 100 grams/2 50 grams/2 25grams…2 half lives have passed b. Solve for the half-life
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9.2 a) 120 b) If the blue balloon expands‚ the angle between red and green balloons decreases. c) Nonbonding (lone) electron pairs exert greater repulsive forces than bonding pairs‚ resulting in compression of adjacent bond angles. 9.12 a) Both molecules would be symmetrical because all four surrounding atoms are the same. In a symmetrical tetrahedron‚ the four bond angles are equal to each other‚ with values of 109.5°. The H-C-H angles in CH4 and the O-Cl-O angles in ClO4- will have
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Apeejay School Kolkata (WEST BENGAL) DEPARTMENT OF CHEMISTRY This is to satisfy that Ritika Kataruka bearing Roll no _______ Studyng in class XII (Science) of this institution has successfully completed the Chemistry Project. “To Study the quantity of casein present in different samples of Milk” Based on the syllabus of C.B.S.E. council for the session 2013-2014 AISSCE under my guidance and supervision and has given satisfactory account
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Kull Key Chemistry 105 Practice Test 3 Spring 2007 Student: ________________________ The actual test will have 15 multiple choice‚ select 12 for grading‚ and 5 or 6 workout problems. There are no work-out problems here‚ bur the types of required computations are seen in the multiple choice problems here. I will place an updated equation sheet on the web by Wednesday morning‚ as well as post the answer key. 1 Who proposed a model that successfully explained the photoelectric effect? A
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مدرستنا الثانوية اإلنجليزية‚الشارقة OUR OWN ENGLISH HIGH SCHOOL‚ SHARJAH A GEMS SCHOOL CHEMISTRY WORKSHEET TOPIC: METALS AND NON-METALS GRADE:8 Note: Revise the symbols and valency of metals and non-metals. Q1.What would you observe when you put a) Some zinc pieces into blue copper sulphate solution? b) Some copper pieces into green ferrous sulphate solution? c) An iron nail into blue copper sulphate solution? Q2.Complete and balance the following equations: a) Zn + O2 b) Pb + O2 c) Cu
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REVIEW a. I‚. • • C • • c. • C 3. The effective nuclear charge is a. equal to the suns of the charges of the protons in the nucleus b. equal to the suns of the charges of the protons in the nucleus minus the sum of the electrons in the Outer shell c. lest than tire sum of the charges of the protons in the nucleus due to shielding by the electrons in the outer shell d. lest than the sum of the charges of the protons in tire nucleus due to nisielding by the
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Compleximetric Determination of Water Hardness Caindec‚ Patricia Ysabel B. Water hardness is a measure of the amount of calcium and magnesium carbonate dissolved as Ca 2+ and Mg 2+ in water. There are no health hazards associated with water hardness‚ however‚ it causes scaling‚ as well as forming of soap suds. Compleximetric titration is one of the best ways of measuring total water hardness using a standard ethylenediaminetetraacetic acid (EDTA) solution. EDTA solution is used as it has the
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Introduction An atom is the smallest part of an element that can take part in a chemical change. The word “atom” comes from the Greek “atomos”‚ which means “unable to be cut”. Atomism is the philosophy of the existence of atoms. The first theories of atoms come from India. There was a Hindu sage named Kanad that hypothesized that all mater was composed of earth‚ water‚ light‚ wind‚ ether‚ time‚ space‚ mind and soul. Then another philosopher named Pakuda Katyayana suggested that everything can be
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Heat of Neutralization Introduction: The purpose of this experiment was to measure‚ using a calorimeter‚ the energy changes accompanying neutralization reactions. In order to measure the amount of heat produced by a reaction‚ an instrument called a calorimeter was used. The calorimeter used in this experiment was somewhat rudimentary. It was constructed as shown in the following picture: After finding the heat capacity of the calorimeter‚ the student and partner neutralized two acids and
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An example of potential energy is A) a coiled spring. B) running water. C) tree branches blowing in the breeze. D) a moving elevator. E) electrical energy. Points Earned: 1.0/1.0 The correct answer is A. The definition of potential energy is an inactive type of energy that is stored for future use. All of these answers describe active energy‚ for example‚ running water is very active but can generate other types of energy. Which one of the following substances will float in gasoline
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