CHM 141 Lecture Notes - Lecture 3: Unified Atomic Mass Unit, Relative Atomic Mass, Weighted Arithmetic Mean

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raspberryseal563

19 Sep 2016

School

Miami University

Department

Chemistry & Biochemistry

Course

CHM 141

Professor

Stewart Robert

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Isotopes: atoms having the same z (atomic #) but different mass # (a) = different number of neutrons. Atomic weight (aw) weighted average mass of all isotopes of an element average atomic mass (units = amu) Ma= mass of a in amu fa= fractional abundance of isotope a fb= fractional abundance of isotope b. Mc=mass of c in amu fc=fractional abundance of isotope c. Aw of x= mafa + mbfb +mcfc units=amu. Periodic table: horizontal rows= periods, vertical columns=groups (families, elements arranged in order of increasing z (atomic #, elements in same group have similar chemical properties = periodic .

Related Questions

Part A and B

For problems 11 through 13, show your work to receive full credit and use the correct number of significant figures in your final answer. 11. The density of nickel is 8.91 g/cm3. Calculate the mass of a nickel ball with a radius of 0.50 mm in grams. (Ï = 3.1416; Vsphere = 4Ïr3/3) 12. The recommended adult dose of Elixophyllin , a drug used to treat asthma, is 6.00 mg/kg of body mass. Calculate the dose in milligrams for a 134-lb person. 13. It is 273 K outside. Do you need a jacket? Why or why not? (show your work for full credit) 14) Element X has three naturally occurring isotopes. The masses (amu) and % abundances of the isotopes are given in the table below. What is the average atomic mass of the element in amu? isotope38 abundance of 5.07,mass of 37.919 isotope39x,abundance of 15.35,mass of 39.017 isotope 42,abundance of 79.85,mass of 42.111 15. Classify each of the following elements as alkali, alkaline earth, halogen or a noble gas: a) He ________________________ b) F ________________________ c) Na ________________________ d) Ca ________________________ e) Br ________________________

CHM 141 Lecture Notes - Lecture 3: Unified Atomic Mass Unit, Relative Atomic Mass, Weighted Arithmetic Mean

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