Significant numbers, also known as significant figures, are the digits in a number that contribute to its precision. They are important in chemistry because they indicate the level of accuracy and precision in a measurement, which is crucial for conducting experiments and analyzing data.
The following rules can help determine the number of significant figures in a given number:1. All non-zero digits are significant.2. Zeros between non-zero digits are significant.3. Zeros at the beginning of a number are not significant.4. Zeros at the end of a number after a decimal point are significant.5. Zeros at the end of a whole number may or may not be significant, depending on the context.
Accuracy refers to how close a measurement is to the true or accepted value, while precision refers to how close a set of measurements are to each other. In other words, accuracy is related to correctness and precision is related to consistency.
When performing mathematical calculations, the final answer should be rounded to the same number of significant figures as the measurement with the lowest number of significant figures. For addition and subtraction, the answer should be rounded to the least number of decimal places. For multiplication and division, the answer should be rounded to the least number of significant figures.
Scientific notation is used in chemistry to express very large or very small numbers in a more convenient and concise way. To determine the number of significant figures in scientific notation, count all the digits in the coefficient (the number before the "x10") and include any non-zero digits in the exponent. For example, 1.23 x 10^4 has three significant figures (1, 2, and 3).