Chemistry

CHEM& 140 – Checkpoint 3 – Show It HW Name ______________________________ Section ____

The notation at the beginning of each problem refers to the location of the problem in the textbook (6th edition of Introductory Chemistry by Tro). Most odd-numbered problems have answers in the back of the book. When a problem states “Show your work using dimensional analysis”, you must show your calculation setup including units and showing how the units cancel out in order to receive credit for the problem.

Make sure to read pages 29-32 in the textbook before starting this HW. (Click on IA Course Materials in Canvas.)

1. Find the CHEM& 140 Periodic Table of Elements and Provided Info sheets that you’ll use for quizzes in this class. (See Course Orientation module.) Classify each unit on the info page according to type of measurement. Write the unit abbreviations. An example using time is shown.

· time: s, min, h

· length:

· mass:

· volume:

2. Explain why units are important in calculations.

3. What is a conversion factor?

4. Using the relationship 1 gallon = 3.785 liters, write the conversion factor that would be used to perform each conversion. Use correct unit abbreviations! For example, g is not correct for gallon and l is not correct for liter.

gallons to liters

liters to gallons

5. Draw a solution map to convert a measurement in milliliters to gallons. (See page 30 or 33 for help.) Use the following specific relationship: 1 gallon = 3.785 liters. And, you might need to find one more relationship on your own to use.

6. Draw a solution map to convert a measurement in ounces to grams. (See page 30 or 33 for help.) Use the following specific relationships: 1 pound = 16 ounces; 1 kilogram = 2.205 pounds

7. Based on your reading of the Problem Solving Strategy section,

· What is often the hardest part of problem solving? What tips are given to handle this?

· What step is often overlooked in problem solving? Why is it important or helpful to do?

8. Create your own metric system scale including all metric prefixes you are responsible for memorizing (name, abbreviation, mathematical meaning). You may insert your metric scale here or attach as an additional page.

9. Perform each metric conversion. Show your work using dimensional analysis.

· (CH2 #69c) 4598 mg to kilograms

Thinking operations/questions before you start: Write in the abbreviation for kilograms. Label the units to indicate which is the smaller unit and which is the larger unit. Then, should the value get smaller or larger when converting from milligrams to kilograms?

· (CH2 #71b) 3.41 x 10 – 5 g to micrograms

Thinking operations/questions before you start: Write in the abbreviation for micrograms. Label the units to indicate which is the smaller unit and which is the larger unit. Then, should the value get smaller or larger when converting from g to micrograms?

10. (CH2 #76a,c,d) Perform each conversion that involves both the metric and imperial unit systems. Show your work using dimensional analysis.

0. (CH2 #75a) 40.0 centimeters to inches

0. 7.5 liters to quarts

0. (CH2 #75d) 3845 kilograms to pounds