Using a Calculator

You can use a calculator to add and subtract numbers in exponential notation without first converting them to the same power of ten. The only thing you need to be careful about is entering the exponential number correctly. I m going to show you how to do that right now  

I assume that your calculator has a key labeled EXP. The EXP stands for x 10. After you press the EXP key, you enter the power. For example, to enter the number 6.25 x 10, you type 6.25, press the EXP key, and then type 3. 

When using a scientific calculator, don t enter the x 10 part of your exponential number. Press the EXP key to enter this part of the number. 

Get to know your own calculator each calculator is slightly different in its mode of operation. Some of the most frequently used calculations covered by these exercises are  

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Exponential (or ordinary) numbers are readily raised to powers using a calculator. To square a number, use the x2 key. For example,... 

To obtain a base-10 logarithm using a calculator, all you need to do is enter the number and press the [log] key. This way you should find that... 

No matter how you decide to use the book, you will find it most helpful if you do not use a calculator,... 

Worked Example 6.4 Without using a calculator, what is the concentration of HNO3 solution if its pH is 4 ... 

For an example of the kinds of decisions that involve the time value of money, examine the advertisement in Figure 3.1. For which option do you receive the most value Answers to this and similar questions sometimes may be quickly resolved using a calculator or computer without much thought. To understand the underlying assumptions and concepts behind file calculations, however, you need to account for cash flows in and out using the investment time line diagram for a project. Look at Figure 3.2. 

Calculations — These questions require you to quickly calculate mathematical solutions. Since you will not be allowed to use a calculator for the multiple-choice questions, the questions requiring calculations have been limited to simple arithmetic so that they can be done quickly, either mentally or with paper and pencil. Also, in some questions, the answer choices differ by several orders of magnitude so that the questions can be answered by estimation. 

Another way to do this step, if you could use a calculator, would be... 

You may NOT use a calculator for this section of the exam. You will be given 10 minutes to answer FIVE of the eight options in this part. (Answers to more than five options will not be scored.)... 

You will receive a test booklet for the free-response section of the test. You will have 95 minutes to answer six questions. These questions may cover any of the material in the AP Chemistry course. Section II consists of two parts. In the first part, you may use a calculator. You will have 55 minutes to answer three questions, the first of which will deal with equilibrium. In the second part, you may not use a calculator. You will have 40 minutes to answer three questions, the first of which will be a reaction question. One of the free-response questions will address laboratory work. The first part will account for 60% of your... 

The following problems refer to different chapters in the book. It is not important whether you get the correct answers. If you have a problem with one or more questions from a chapter, review the chapter. You may use a calculator and the periodic table. For each question, circle the letter of your choice. 

Answer the following questions. You have 25 minutes. You may not use a calculator. You may use the periodic table in the back of the book. 

You have 20 minutes to do the following question. You may use a calculator and the tables at the back of the book. 

The AP exam is a timed exam keep this in mind as you prepare. When taking the various tests presented in this book, you should follow the AP exam rules as closely as possible. Anyone can improve his or her score by using notes, books, or an unlimited time. You will have none of these on the AP exam, so resist the temptation to use them on practice exams. Carefully time yourself do not use other materials and use a calculator only when expressly allowed to do so. After you have finished an exam, you may use other sources to go over questions you missed or skipped. We have seen many students get into trouble because the first time they attempted a test under test conditions was on the test itself. 

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