Exam 1 Study Guide - General Chemistry I | CHEM 102, Study notes of Chemistry

Download Exam 1 Study Guide - General Chemistry I | CHEM 102 and more Study notes Chemistry in PDF only on Docsity! Announcements The review questions and answers are posted on the website. If you need to sign up for the conflict exam please do so by 4pm TODAY outside 101 Chemistry Annex, the conflict exam will be held from 5:30-6:45 pm in 140 Burrell on Thursday February 18th. You will receive the answers after the exam, therefore you will be able to grade yourselves. Summary Chapter One 1. Scientific Method (know definitions) (1) 2. Quantitative versus Qualitative measurements (1) 3. Accuracy versus Precision (1) 4. Significant Figures (1) 5. Dimensional Analysis (multiple questions – indirectly) 6. Density (1) 7. Classification of Matter (2) Summary Chapter Two 1. There are lots of names and dates in this chapter, what was covered in class is what I find important 2. Dalton –Dalton’s atomic theory* 3. J.J. Thomson – cathode ray experiment and plum pudding model* 4. Rutherford – alpha-particle bombardment experiment* 5. Nuclear Atom (1) 6. Isotopes (1) 7. Periodic Table (groups, periods, metals, nonmetals) (1) 8. Memorize names of elements 1-36, Tables 2.5-2.8** 9. Simple molecule formation** 10. Nomenclature of ionic and covalent compounds** *1 question for items 2, 3, 4 ** 9 questions Isotopes Identify the isotope which has a mass number of 185 and whose +3 ion has 72 electrons: a) b) c) d) e) Ir18577 Ir18877 Re18575 Tm18569 Tm25469 Conceptual Question Which of the following statements is FALSE? a) An atom is mostly empty space. b) Glucose (C6 H12 O6 ) is an example of a covalent compd. c) CaF2 contains an alkali metal and a halogen. d) When a metal forms a compound with a nonmetal, an ionic compound generally results. e) Metals generally form stable cations in ionic compounds. Mass % A binary compound between an unknown element E and hydrogen contains 91.27 % E and 8.73% H by mass. If the formula is E3 H8 , what is the identity of E? Combustion Analysis A sample of LSD (D-lysergic acid diethylamide, C24 H30 N3 O) is added to some table salt (sodium chloride) to form a mixture. Given that a 1.00 g sample of the mixture undergoes combustion to produce 1.20 g of carbon dioxide, what is the mass % of LSD in the mixture? Stoichiometry For the next two questions, consider the following reaction between two hypothetical elements A and B: 2A (g) + 3B3 (g) → A2 B9 (g) Molar masses: A: 40.0 g/mol; A2 B9 : 125 g/mol Initially a reaction vessel contains 11.0 moles of A and 12.0 moles of B3 . Assuming the above reaction goes to completion answer the following questions: 1. If 4.0 moles of A2 B9 are formed in the reaction, how many moles of A are left unreacted? 2. What is the total mass of B3 consumed in the reaction? Dilution A solution is made by mixing 50.0 mL of 6.00 M HCl with 400.0 mL of 0.250 M HCl. This mixture is diluted by adding water until the final solution volume is 800.0 mL. What is the molarity of the final solution of HCl? Precipitation Reactions Consider the following information for the next three questions. 100.0 mL of 0.100 M lead (II) nitrate is added to 75.0 mL of 0.100 M ammonium phosphate and a precipitate forms. 1. What is the net ionic equation. 2. How many moles of precipitate are formed assuming 100% yield? 3. Calculate the molarity of ammonium ions after the precipitation is complete. Titration What volume of 0.0521 M Ba(OH)2 is required to react completely with 14.20 mL of 0.141 M H3 PO4 ? Phosphoric acid contains three acidic hydrogens. Ideal Gas Behavior Which of the following statements is false concerning ideal gases? a) For a mixture of gases, the total pressure is the sum of the partial pressures of all the gases present. b) At constant P and n, a plot of volume (L) vs. temperature(K) is linear. c) At constant V and T, the moles of gas present is inversely related to the pressure of the gas sample. d) At constant n and T, as the volume of a gas sample increases, the pressure of the gas decreases. e) At constant P and T, a 2.0 L sample of N2 (g) contains twice the number of molecules as a 1.0 L sample of O2 (g). Two Condition Problem An ideal gas in a flexible container occupies a volume of 10.0 L at 38ºC and 0.20 atm. If the gas sample is cooled to 7ºC and the volume is decreased to 3.60 L, what is the new pressure of the gas sample? Ideal Gas The gases N2 and H2 in a closed container fitted with a movable piston (the piston allows the volume of the container to change in order to keep the pressure constant). Stoichiometric amounts of the gases are chosen so that neither is limiting (after the reaction below goes to completion, no N2 or H2 are present). If the original volume of the container is 8.0 L, what will be the volume of the container after the following unbalanced reaction goes to completion? Assume P and T are constant. N2 (g) + H2 (g) → NH3 (g)