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Ch.1 - Introduction: Matter, Energy, and Measurement
Brown - Chemistry: The Central Science 14th Edition
Brown14th EditionChemistry: The Central ScienceISBN: 9780134414232당신이 사용하는 게 아니라요?교과서 변경
1장, 문제 11

Consider the jar of jelly beans in the photo. To get an estimate of the number of beans in the jar you weigh six beans and obtain masses of 3.15, 3.12, 2.98, 3.14, 3.02, and 3.09 g. Then you weigh the jar with all the beans in it, and obtain a mass of 2082 g. The empty jar has a mass of 653 g. Based on these data, estimate the number of beans in the jar. Justify the number of significant figures you use in your estimate.

검증된 단계별 안내
1
Calculate the average mass of a single jelly bean by adding the masses of the six beans and dividing by six: \( \text{Average mass} = \frac{3.15 + 3.12 + 2.98 + 3.14 + 3.02 + 3.09}{6} \).
Determine the total mass of the jelly beans by subtracting the mass of the empty jar from the mass of the jar with beans: \( \text{Total mass of beans} = 2082 \text{ g} - 653 \text{ g} \).
Estimate the number of jelly beans by dividing the total mass of the beans by the average mass of a single bean: \( \text{Number of beans} = \frac{\text{Total mass of beans}}{\text{Average mass of a bean}} \).
Consider the significant figures in your calculations: the average mass of a bean should be reported with the same number of decimal places as the least precise measurement, and the total mass of beans should be calculated with the precision of the subtraction operation.
Use the appropriate number of significant figures in your final estimate of the number of beans, based on the precision of the measurements used in the calculations.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m

주요 개념

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

Mass and Weight Measurement

In chemistry, mass is a measure of the amount of matter in an object, typically measured in grams. Weight, while often used interchangeably with mass, refers to the force exerted by gravity on that mass. Accurate mass measurements are crucial for calculations in stoichiometry and determining quantities in chemical reactions.
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Units of Radiation Measurement

Significant Figures

Significant figures are the digits in a number that contribute to its precision. This concept is essential in scientific measurements, as it reflects the certainty of the data collected. When performing calculations, the result should be reported with the same number of significant figures as the measurement with the least number of significant figures to maintain accuracy.
추천 영상:
가이드 코스
01:09
Significant Figures Example

Estimation and Calculation of Quantity

Estimating the number of jelly beans involves calculating the total mass of the beans and then dividing by the average mass of a single bean. This process requires understanding how to manipulate mass data and apply basic arithmetic to derive a meaningful quantity. The average mass is calculated from the measured masses of the six beans, which is then used to estimate the total number of beans in the jar.
추천 영상:
가이드 코스
02:28
Stoichiometric Rate Calculations