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Unformatted text preview: nanni (arn437) – Chemistry Warmup – CNS – (87654) 1 This printout should have 32 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Simplify parenleftbigg u 3 2 w parenrightbigg 4 Your answer should be written with all ex ponents expanded as far as they can go. De note division using \ , and use the minimum number of parenthesis consistent with order of operations. Correct answer: u 1 2 / (16 w 4 ). Explanation: First we expand the exponent over the things included in the outer parenthesis, and then we simplify as much as we can: parenleftbigg u 3 2 w parenrightbigg 4 = ( u 3 ) 4 ( 2) 4 w 4 = u 1 2 16 w 4 002 10.0 points Simplify (2 z 5 w 3 )(5 w 7 )(2 z ) Your answer should be written with all ex ponents expanded as far as they can go. De note division using \ , and use the minimum number of parenthesis consistent with order of operations. Correct answer: 20 * ( z 6 ) * ( w ( 10)). Explanation: We simply multiply all the like terms, re membering that ( a n )( a m ) = a n + m . So, the right answer is 2 · 5 · 2 z 5+1 w 3+7 = 20 z 6 w 10 003 (part 1 of 4) 10.0 points Balance the following chemical equation by finding values for a,b,c, and d. a C 2 H 5 OH(l) + b O 2 (g) → c CO 2 (g)+ d H 2 O(g) What is a? Correct answer: 1. Explanation: In a chemical reaction matter is neither created nor destroyed. So, we proceed by counting elements on both sides. C 2 H 5 OH(l) + O 2 (g) → CO 2 (g)+ H 2 O(g) Carbon appears only once on each side of the equation, so to balance the C, we put a 2 in front of the CO 2 and a 1 in front of the C 2 H 5 OH(l) Next the hydrogen. Each molecule of C 2 H 5 OH contains 6 hydrogen atoms. To bal ance the H, we put a 3 in front of the water. Finally, we match the oxygen in the prod ucts with the number of oxygen atoms needed in the reactants. On the right hand side of the equation we have 7 oxygen atoms. To balance the oxygen we recognize that there is 1 oxygen atom in C 2 H 5 OH(l) so we need to put a 3 in front of the O 2 (g) The balanced reaction is: 1 C 2 H 5 OH(l) + 3 O 2 (g) → 2 CO 2 (g)+ 3 H 2 O(g) 004 (part 2 of 4) 10.0 points What is b? Correct answer: 3. Explanation: See the explanation for part 1. 005 (part 3 of 4) 10.0 points What is c? Correct answer: 2. Explanation: See the explanation for part 1. 006 (part 4 of 4) 10.0 points What is d? nanni (arn437) – Chemistry Warmup – CNS – (87654) 2 Correct answer: 3. Explanation: See the explanation for part 1. 007 10.0 points Calculate the volume of a sphere with radius of 3.0 μ m. Answer in cm 3 , to 2 significant digits. Note : Volume formulae are provided in ALEKS Your answer must be within ± 5.0% Correct answer: 1 . 1 × 10 10 cm 3 ....
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This note was uploaded on 09/19/2011 for the course CH 301 taught by Professor Fakhreddine/lyon during the Fall '07 term at University of Texas.
 Fall '07
 Fakhreddine/Lyon

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