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Ch.1 - Matter, Measurement & Problem Solving
Tro - Chemistry: A Molecular Approach 6th Edition
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217당신이 사용하는 게 아니라요?교과서 변경
1장, 문제 86

Round each number to three significant figures. a. 79,845.82 b. 1.5148937×107 c. 1.13499999995 d. 0.0000415389

검증된 단계별 안내
1
1. To round a number to three significant figures, you need to look at the fourth digit. If the fourth digit is 5 or more, you round up the third digit. If it's less than 5, you leave the third digit as it is.
2. For 79,845.82, the fourth digit is 8, which is more than 5. Therefore, you round up the third digit, which is 9, to the next number, which is 0. However, since 9 is the maximum digit, you also need to round up the second digit, which is 8, to the next number, which is 9. The result is 80,000.
3. For 1.5148937 * 107, the fourth digit is 8, which is more than 5. Therefore, you round up the third digit, which is 4, to the next number, which is 5. The result is 1.52 * 107.
4. For 1.13499999995, the fourth digit is 9, which is more than 5. Therefore, you round up the third digit, which is 4, to the next number, which is 5. The result is 1.14.
5. For 0.0000415389, the fourth significant digit is 5, which is equal to 5. Therefore, you round up the third significant digit, which is 1, to the next number, which is 2. The result is 0.000042.

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주요 개념

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

Significant Figures

Significant figures are the digits in a number that contribute to its precision. This includes all non-zero digits, any zeros between significant digits, and trailing zeros in the decimal portion. Understanding how to identify and count significant figures is crucial for rounding numbers accurately.
추천 영상:
가이드 코스
01:09
Significant Figures Example

Rounding Rules

Rounding rules dictate how to adjust numbers to a specified number of significant figures. When rounding, if the digit following the last significant figure is 5 or greater, the last significant figure is increased by one. If it is less than 5, the last significant figure remains unchanged.
추천 영상:
가이드 코스
00:28
Solubility Rules

Scientific Notation

Scientific notation is a way of expressing numbers that are too large or too small in a compact form, using powers of ten. For example, 1.5148937 * 10^7 is a representation of a large number. Understanding how to manipulate and round numbers in scientific notation is essential for accurate calculations in chemistry.
추천 영상:
가이드 코스
02:50
Standard Notation to Scientific Notation