Homework 1-solutions

# Homework 1-solutions - fernandez(jf23742 Homework 1...

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fernandez (jf23742) – Homework 1 – Brodbelt – (53765) 1 This print-out should have 22 questions. Multiple-choice questions may continue on the next column or page – Fnd all choices before answering. This homework is due September 10 at 11:00 pm. 001 10.0 points What is the symbol for the element copper? 1. Cr 2. Co 3. Cp 4. Cu correct Explanation: The symbol for copper is Cu. 002 10.0 points A factor of 1 . 0 × 10 - 9 corresponds to the preFx 1. milli. 2. pico. 3. micro. 4. nano. correct Explanation: Nano refers to 1 . 0 × 10 - 9 . 003 10.0 points Express 0.0103240 in scientiFc notation. 1. 1 . 03240 × 10 - 3 2. 1 . 03240 × 10 - 2 correct 3. 1 . 0324 × 10 - 1 4. 1 . 0324 × 10 - 2 5. 1 . 0324 × 10 - 3 6. 1 . 03240 × 10 2 Explanation: The number is a fraction smaller than one, so the exponent is negative. The decimal must be moved 2 places, so the exponent on 10 must be - 2. 004 10.0 points What is the proper solution to the following equation? (150 + 2 . 5 + 36 . 75) ÷ (6 . 60 + 0 . 173) = 1. 27.942 2. 28 correct 3. 27.9418 4. 27.94 5. 30 6. 27.94183 7. 27.9 Explanation: The last position retained for the Frst addi- tion problem will be the tens position giving it 2 sigFgs. The last position retained for the second addition problem will be the hun- dredths position giving it 3 sigFgs. Therefore the Fnal answer 27.94 needs to be rounded to 2 sigFgs: 28. 005 10.0 points How many kg are in 10.0 mg? 1. 1 . 00 × 10 - 7 kg 2. 1 . 00 × 10 - 3 kg 3. 1 . 00 × 10 - 6 kg 4. 1 . 00 × 10 - 5 kg correct 5. 1 . 00 × 10 - 4 kg Explanation: ? kg = 10 . 0 mg × 1g 1000 mg × 1 kg 1000 g =1 × 10 - 5 kg

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fernandez (jf23742) – Homework 1 – Brodbelt – (53765) 2 006 10.0 points How many cubic inches (in 3 ) are in a 55.1 liter aquarium? 1. 162 in 3 2. 3360 in 3 correct 3. 18,700 in 3 4. 129 in 3 5. 23.3 in 3 Explanation: ? in 3 = 55 . 1L × 1000 mL 1L × 1 cm 3 1 mL × ± 1 in 2 . 54 cm ² 3 = 3360 in 3 007 10.0 points Calculate the density of methanol (CH 3 OH) if you know that there are 4.2 moles of methanol in 5.67 L. 1. 0.741 g/mL 2. 0.131 g/mL 3. 1334 g/mL 4. 0.0431 g/mL 5. 11.34 g/mL 6. 0.0237 g/mL correct Explanation: n =4 . 2 mol V =5 . 67 L d = 4 . 2 mol CH 3 OH 5 . 67 L × 32 g CH 3 OH 1 mol CH 3 OH × 1L 1000 mL =0 . 0237 g / mL 008 10.0 points
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## This note was uploaded on 07/27/2009 for the course CH 89959 taught by Professor Cowley during the Spring '09 term at University of Texas.

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Homework 1-solutions - fernandez(jf23742 Homework 1...

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