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Ch.2 Chemistry and Measurements
Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 13th Edition
Timberlake13th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9780134421353Not the one you use?Change textbook
Chapter 2, Problem 17b

Identify the numbers in each of the following statements as measured or exact:
b. A patient is given 2 tablets of medication.

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1
Step 1: Understand the difference between measured and exact numbers. Measured numbers are obtained through measurement and have a degree of uncertainty, while exact numbers are counted or defined and have no uncertainty.
Step 2: Analyze the given statement: 'A patient is given 2 tablets of medication.'
Step 3: Recognize that the number '2' in this context refers to a count of tablets, which is a discrete quantity.
Step 4: Recall that counted numbers, such as the number of tablets, are considered exact because they are not subject to measurement uncertainty.
Step 5: Conclude that the number '2' in this statement is an exact number.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Measured Numbers

Measured numbers are values obtained through measurement and are subject to uncertainty. They include any quantity that can vary, such as weight, height, or temperature. The precision of measured numbers is limited by the measuring instrument used, which introduces a degree of error.
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Exact Numbers

Exact numbers are values that are counted or defined and have no uncertainty associated with them. They are typically whole numbers, such as the number of students in a classroom or the number of tablets prescribed. Exact numbers are considered to have infinite precision and do not change regardless of the measuring context.
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Contextual Interpretation

Understanding whether a number is measured or exact often depends on the context in which it is presented. In the example of '2 tablets of medication,' the number is exact because it refers to a specific count of tablets, which is defined and does not involve measurement uncertainty. Contextual interpretation helps clarify the nature of the numbers in various scenarios.
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