Empirical formula 12456ref, Summaries of Chemistry

Download Empirical formula 12456ref and more Summaries Chemistry in PDF only on Docsity! Chemistry 101L Experiment 2: Empirical Formula and Avogadro’s Number Pre- lab Assignment Name:_________________ Date:___________________ ID #:__________________ Section:_________________ 1. An analysis shows that 5.85 g of a chromium metal combines with oxygen to form 8.62 g of chromium oxide. What is the empirical formula of the compound? 2. The formula for rust can be represented by Fe2O3. a) How many moles of Fe2O3 are present in 24.6 g of the compound? b) How many moles of Fe are present in 24.6 g of the compound? c) How many atoms of oxygen are present in 24.6 g of the compound? 3. Zinc metal has a hexagonal close packed structure. Calculate the volume of a unit cell of Zn in cm3. Chemistry 101L Experiment 2: Empirical Formula and Avogadro’s Number Lab Report Name: _____________________ Date: _________________ Purpose of the experiment: Part 1 Data : Mass of 125 mL Erlenmeyer flask = Mass of 125 mL Erlenmeyer flask + zinc granules = Mass of 125 mL Erlenmeyer flask + zinc granules + iodine= Mass of 150 mL beaker = Mass of Erlenmeyer flask + unreacted zinc = Mass of beaker + zinc iodide = Calculations: Mass of zinc granules = Mass of iodine = Mass of iodine + zinc (before reaction) = Mass of unreacted zinc = Mass of zinc iodide = Mass of reacted zinc = Mass of reacted iodine + reacted zinc = Mass of unreacted zinc + product = Moles of reacted zinc = Moles of reacted iodine = Ratio of moles of one element to the other = Empirical formula of zinc iodide = Questions 1. Write a balanced chemical equation for the reaction of zinc with iodine. 2. Show by referring to calculations whether mass is conserved in a chemical reaction.