WA3_CHE-121-jul16 - Name Vaughn Copeland College ID 0562024 Thomas Edison State University General Chemistry I with Labs(CHE-121 Section no Module 3

# WA3_CHE-121-jul16 - Name Vaughn Copeland College ID 0562024...

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Name: Vaughn Copeland College ID: 0562024 Thomas Edison State University General Chemistry I with Labs (CHE-121) Section no.: Module 3 Semester and year: 03-16 Written Assignment 3: Mass Relationships for Compounds Answer all assigned questions and problems, and show all work. 1. How many atoms are there in 5.10 moles of sulfur (S)? (6 points)   (5.10 mol)(6.02e23 atoms/mol)=3.07e24 atoms (Reference: Chang 3.13) 2. How many moles of calcium (Ca) atoms are there in 77.4 g of Ca? (6 points) 77.4 g Ca * ( 1 mole Ca/ 40.08 g Ca ) = 1.93 mol Ca (Reference: Chang 3.15) 3. What is the mass in grams of 1.00 × 10 12 lead (Pb) atoms? (8 points) (1.00x10^12)(207.2.) / 6.02x10^23 = 3.44x10^-10 g (Reference: Chang 3.19) 4. Describe how you would determine the isotopic abundance of an element from its mass spectrum. (6 points) Mass spectrometer (Reference: Chang 3.32) 5. Cinnamic alcohol is used mainly in perfumery, particularly in soaps and cosmetics. Its molecular formula is C 9 H 10 O. a. Calculate the percent composition by mass of C, H, and O in cinnamic alcohol. (8 points)

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