Chemistry 112 Form C Fetzer Gislason

Transcription

1 Exam 1 February 10, 2003 There are 20 questions at 5 points each. The last page contains a periodic table and a solubility table. You should tear off the last page to use as reference. Directions: 1) Put your name on all sheets. 2) Work out multiple choice problems and transfer your answers to the scantron. 3) Hand in both the scantron sheet and your exam. Scantron sheet: 1) Print name (last name, first name) and fill in the corresponding bubbles. 2) Sign your name where it says signature. 3) Write: Chem112, TA s name, Form (A or B) on bottom right where it says course number and instructor. 4) Hand in both the scantron sheet and the exam to your TA.

2 1) All atoms of a given element have the same a) mass b) number of neutrons c) number of protons d) number of electrons and neutrons e) density 2) An atom of the most common isotope of gold, 197 Au 3+, has protons, neutrons, and electrons. a) 197, 79, 118 b) 118, 79, 39 c) 79, 118, 79 d) 79, 118, 118 e) 79, 118, 76 3) How many significant figures should be retained in the answer of the following calculation? ( ) a) 1 b) 2 c) 3 d) 4 e) 5 4) The names of Ni(CN) 2 and HClO are a) nickel (I) cyanide and hydrogen chlorine monoxide b) nickel (II) cyanide and hypochlorous acid c) nickel cyanate and hydrochlorous acid d) nickel carbonate and chloric acid e) nickel (II) cyanide and perchlorous acid 5) How many atoms of H are in 65 g of C 2 H 4 O 2 (molar mass = g/mol)? a) b) c) d) e) ) In the demo on electrical conductivity, which of the following demonstrated electrical conductivity by causing the light to glow? 1. CuCl 2 (aq) 2. C 2 H 5 OH(aq) 3. AgNO 3 (s) 4. AgNO 3 (l, melted) 5. C 6 H 12 O 6 (aq) a) 1 & 4 b) 1,3 & 5 c) 2 & 5 d) 1, 2, & 5 e) all of these 7) What is the coefficient of O 2 when the following equation is balanced? C 5 H 8 O 3 + O 2 CO 2 + H 2 O a) 3 b) 7 c) 5 d) 9 e) 11 1

3 8) Combustion analysis of grams of a compound containing C, H, and O yielded grams H 2 O and grams CO 2. What is the empirical formula of the compound? a) C 3 H 8 O b) C 3 H 5 O c) C 6 H 13 O 2 d) C 3 H 4 O 3 e) C 3 H 5 O 3 9) Which of the following substances is soluble in water? (Consult the solubility table.) 1. Na 2 CO 3 2. CaCO 3 3. CaS 4. K 2 S O 4 5 (NH 4 ) 2 S a) only 1 b) 1, 4, & 5 c) 2 & 3 d) 2 & 4 e) 2 & 3 & 5 10) Which of the following are non-electrolytes? 1. HCl 2. HC 2 H 3 O 2 3. NH 3 4. KCl 5. C 6 H 12 O 6 a) 1 & 4 b) 1, 2, 3, & 4 c) 2 & 5 d) 2 & 3 e) 1, 2, & 4 11) Calculate the maximum mass of AgCl produced when 7.73 g AlCl 3 ( g/mol) reacts with 4.22 g of AgNO 3 ( g/mol) according to the equation, 3 AgNO 3 + AlCl 3 Al(NO 3 ) AgCl a) 3.56 b) 4.22 c) 24.9 d) 17.6 e) ) A strong electrolyte is one that completely in solution. a) reacts b) dissolves c) ionizes d) decomposes e) disappears 2

4 13) Find the pair of isotopes of the same element from the following possibilities. 116 X 2+, 119 X a) X 2+, X b) c) X, 96 X X 2+, X d) e) X, X ) The formula of a compound is XCl 4. The X-ion in this compound has 46 electrons. The neutral metal X is a) Zn b) Sn c) Pd d) Ge e) Xe 15) The formula mass of ammonium carbonate is. a) b) c) d) e) ) How many moles of GeF 4 are needed to form 7.00 mol GeF 3 H according to the following reaction if the product is obtained in 92.6 % yield? GeH GeF 4 4 GeF 3 H a) 5.67 b) 2.00 c) 6.48 d) 7.41 e) ) A bottle weighing grams contains 4.59 cm 3 of an unknown solid. Find the density of the unknown solid if the mass of empty bottle is g. a) 3.10 b) 8.86 c) 2.18 d) 5.76 e) ) What are the formulas of compounds formed between strontium ions and nitrogen ions and between magnesium ions and nitrate ions? a) SrN and Mg(NO 3 ) 2 b) Sr 3 N 2 and Mg(NO 3 ) 2 c) Sr 2 N 3 and Mg(NO 3 ) 2 d) SrN 3 and Mg(NO 3 ) 2 e) Sr 3 N 2 and Mg(NO 2 ) 2 3

5 19) For the reaction, 2 MClO 3 (s) 2 MCl(s) + 3 O 2 (g) we recorded the following data: Mass MClO 3 before heating: g Mass MCl after heating g Using this information, we calculated that M must be a) Li b) Na c) K d) Rb e) Cs 20) In the mole in space demo, how did the mole get into space? Just to remind you, the mole was placed on top of a container in which the following reaction took place: CaC 2 (s) + 2H 2 O(l) C 2 H 2 (g) + Ca(OH) 2 (aq) a) the pressure of the product gas forced the mole up into the air. b) The gas was ignited and the force of the explosion ejected the mole c) The initial reaction evolved enough heat to send Mr. Mole hopping d) The mole was tossed into the air by Lee Marek e) The mole got tired of the whole thing and left of his own accord to seek out his shadow (to get a head start on Mr. Groundhog.) 4

6 Solubility Table: 1. Nearly all ionic compounds of lithium, sodium, potassium, rubidium, cesium, and ammonium are soluble in water. 2. The nitrates and acetates of all metals are soluble. 3. The chlorides, bromides, and iodides of all metals (except silver, lead, mercury(i), and copper(i) )are soluble. 4. The sulfates of all metals (except lead, barium, and calcium) are soluble. 5. The hydroxides of all metals (except those given in rule 1) are insoluble. 6. Carbonates, phosphates, and sulfides are insoluble (except as given in rule 1). 5