solution hw 1 - reyes (mr29667) – Homework 1: Atomic...

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Unformatted text preview: reyes (mr29667) – Homework 1: Atomic Theory – Shear – (52375) 1 This print-out should have 21 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. This homework includes some questions that test basic chemistry knowledge. Some may need you to look things up like atomic masses, fundamental constants, and unit con- versions. Here are some that you may need: c = 3 . 00 × 10 8 m/s h = 6 . 626 × 10- 34 J · s m e = 9 . 11 × 10- 31 kg N A = 6 . 022 × 10 23 mol- 1 Δ E = R parenleftbigg 1 n 2 1- 1 n 2 2 parenrightbigg where R =- 2 . 178 × 10- 18 J ψ n ( x ) = parenleftbigg 2 L parenrightbigg 1 2 sin parenleftBig nπx L parenrightBig E n = n 2 h 2 8 mL 2 n = 1 , 2 , 3 , ··· 001 10.0 points Which of water, iron, ammonia, chromium, radon, and silicon are chemical compounds as opposed to elements? 1. chromium and water 2. iron and silicon 3. water and ammonia correct 4. only water 5. radon and ammonia Explanation: Water (H 2 O) and ammonia (NH 3 ) are com- posed of more than one element and are com- pounds. 002 10.0 points Identify the symbols for the elements phos- phorus, potassium, silver, chlorine, and sul- fur, in that order. 1. K, Ag, Po, Cl, S 2. Ph, Po, Ag, Al, S 3. P, K, Ag, Cl, S correct 4. P, Po, Ag, Cl, S 5. Ph, K, Ag, S, Cl Explanation: The symbol for phosphorus is P, for potas- sium K, for silver Ag, for chlorine Cl, and for sulfur S. 003 10.0 points Convert 30 micrograms to grams. 1. 3 × 10 13 g 2. 3 . × 10- 11 g 3. 3 . × 10- 8 g 4. 30000 g 5. 3 × 10 10 g 6. 3 . × 10- 5 g correct 7. 0.030 g 8. 3 × 10 7 g Explanation: 30 micrograms · parenleftbigg 1 g 10 6 μ g parenrightbigg = 3 . × 10- 5 g 004 10.0 points Find the molar mass for Ba(OH) 2 . 1. 153.31 g/mol 2. 170.32 g/mol 3. 155.33 g/mol 4. 171.35 g/mol correct reyes (mr29667) – Homework 1: Atomic Theory – Shear – (52375) 2 5. 172.34 g/mol Explanation: molar mass of Ba(OH) 2 = ? 1 mol Ba × 137.33 g Ba mol Ba = 137.33 g 2 O mol × 16.00 g O mol O = 32.00 g 2 mol H × 1.01 g O mol H = 2.02 g Molar mass = 171.35 g /mol 005 10.0 points Balance the equation ? CS 2 + ? O 2 → ? CO 2 + ? SO 2 What are the coefficients? 1. 2, 1, 2, 1 2. 2, 1, 1, 2 3. 1, 3, 1, 2 correct 4. 1, 2, 1, 1 5. 1, 2, 1, 2 6. 2, 2, 1, 1 7. 1, 2, 3, 1 Explanation: C is balanced. O is not balanced, but because it is in both products, we will leave that until the end. Let’s start with S. There are 2 S on the left and 1 S on the right so we will add one more S on the right....
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This note was uploaded on 07/24/2010 for the course CH 52375 taught by Professor Ruth during the Spring '09 term at University of Texas.

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solution hw 1 - reyes (mr29667) – Homework 1: Atomic...

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