State How Many Significant Figures Are Proper in the Results of the Following Calculations

Significant figures are an essential aspect of scientific calculations and measurements. They indicate the precision or accuracy of a measured quantity or the result obtained from a calculation. Understanding how to determine the number of significant figures in a calculation is crucial to maintain the integrity and reliability of scientific data. In this article, we will discuss how to determine the proper number of significant figures in the results of various calculations.

Significant Figures in Addition and Subtraction

When adding or subtracting numbers, the rule for determining the number of significant figures is to consider the least number of decimal places among the numbers being added or subtracted. For example, let’s consider the calculation:

23.45 + 6.789

In this case, the first number has two decimal places, while the second number has three decimal places. According to the rule, the answer should be rounded to the least number of decimal places, which is two. Therefore, the result of this calculation would be 30.24, with two significant figures.

Significant Figures in Multiplication and Division

When multiplying or dividing numbers, the rule for determining significant figures is different. In these operations, the number of significant figures is determined by the least number of significant figures in any of the numbers being multiplied or divided. For example, let’s consider the calculation:

2.6 × 4.32

In this case, the first number has two significant figures, while the second number has three significant figures. According to the rule, the answer should be rounded to the least number of significant figures, which is two. Therefore, the result of this calculation would be 11, with two significant figures.

Scientific Notation and Significant Figures

Scientific notation is often used to express very large or very small numbers. In scientific notation, a number is written as a product of a coefficient and a power of 10. For example, the number 1067982 can be written as 1.067982 × 10^6. In scientific notation, the coefficient is written to include all significant figures, and the power of 10 indicates the number of decimal places.

In the given example, the number 1.067982 × 10^6 has seven significant figures. The coefficient includes all the digits in the number, and the power of 10 does not affect the significant figures.

FAQs:

Q: How do I determine the significant figures when there are zeros present in a number?

A: Zeros can be either significant or insignificant, depending on their position in the number. Zeros between non-zero digits are always significant. For example, 305 has three significant figures. However, leading zeros (zeros before the first non-zero digit) are not significant. For example, 0.056 has two significant figures. Trailing zeros (zeros at the end of a number after the decimal point) are significant if they are explicitly stated or if they fall after a decimal point. For example, 10.00 has four significant figures.

Q: Are there any exceptions to the rules of significant figures?

A: Yes, there are certain operations or situations where the rules for significant figures may require additional considerations. For instance, logarithms, exponential functions, and trigonometric functions are exempt from significant figures. Additionally, exact numbers, such as defined constants or integers obtained by counting, are considered to have an infinite number of significant figures.

Q: Why are significant figures important in scientific calculations?

A: Significant figures help maintain the precision and accuracy of scientific calculations and measurements. They provide information about the uncertainty or error associated with a measured or calculated value. By correctly determining the number of significant figures, scientists can convey the appropriate level of precision in their data and prevent misleading results.

In conclusion, understanding how to determine the proper number of significant figures is crucial for accurate scientific calculations. The rules for significant figures differ depending on the type of operation being performed. By following these rules and paying attention to the position of zeros, scientists can ensure the reliability and integrity of their results.