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Ch.1 - Introduction: Matter, Energy, and Measurement
Brown - Chemistry: The Central Science 15th Edition
Brown15th EditionChemistry: The Central ScienceISBN: 9780137542970당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Brown 15th EditionCh.1 - Introduction: Matter, Energy, and Measurement문제 44
1장, 문제 44

Indicate which of the following are exact numbers: (a) the mass of a 32-oz bag of sugar, (b) the number of students in your chemistry class, (c) the temperature of the surface of the Sun, (d) the mass of a postage stamp, (e) the number of milliliters in a cubic meter of water, (f) the average height of NBA basketball players.

검증된 단계별 안내
1
Understand that exact numbers are those that are counted or defined, not measured.
Consider (a) the mass of a 32-oz bag of sugar: This is a measured quantity, so it is not exact.
Consider (b) the number of students in your chemistry class: This is a counted quantity, so it is exact.
Consider (c) the temperature of the surface of the Sun: This is a measured quantity, so it is not exact.
Consider (e) the number of milliliters in a cubic meter of water: This is a defined quantity (1 cubic meter = 1,000,000 milliliters), so it is exact.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
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45s

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

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 class or the number of milliliters in a liter. Unlike measured quantities, exact numbers do not vary and are considered to have an infinite number of significant figures.
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Measured Numbers

Measured numbers are values obtained through measurement and inherently include some degree of uncertainty. For example, the mass of a bag of sugar or the temperature of the Sun are measured quantities, as they depend on the precision of the measuring instrument used. These numbers are subject to significant figures, which reflect the precision of the measurement.
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Significant Figures

Significant figures are the digits in a number that contribute to its precision, including all non-zero digits, any zeros between significant digits, and trailing zeros in the decimal portion. Understanding significant figures is crucial when performing calculations with measured numbers, as it helps convey the accuracy of the measurements and ensures that results are reported with appropriate precision.
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Significant Figures Example
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