1. Chemistry Item 01-06 Which number contains 2 significant figures? A. 14.00 B. 0.00014 C. 0.0140 D. 140.0 www.upcatreview.com
2. Chemistry Item 01-06 As mentioned, significant figures or digits are those digits in a measurement that are known with certainty and the last digit uncertain or estimated. Some helpful rules/guidelines in determining the number of significant digits are as follows: www.upcatreview.com
3. Chemistry Item 01-06 General Guidelines in Determining Significant Figures (SF) A. Non-zero digits are always SIGNIFICANT. So the number 5432 has 4 SF. www.upcatreview.com
4. Chemistry Item 01-06 General Guidelines in Determining Significant Figures (SF) B. ZEROS may or may not be considered significant. If zeros are: In between two non-zero digits, they are SIGNIFICANT. Thus 106 has 3 SF. www.upcatreview.com
5. Chemistry Item 01-06 General Guidelines in Determining Significant Figures (SF) B. ZEROS may or may not be considered significant. If zeros are: At the right of a decimal point and a non-zero digit, they are SIGNIFICANT. The example 66.0 has 3 SF. www.upcatreview.com
6. Chemistry Item 01-06 General Guidelines in Determining Significant Figures (SF) B. ZEROS may or may not be considered significant. If zeros are: Used to locate a decimal point or used as place holders, they are NOT SIGNIFICANT. For example 0.132500 - 6 SF 0.00502 - 3 SF www.upcatreview.com
7. Chemistry Item 01-06 General Guidelines in Determining Significant Figures (SF) B. ZEROS may or may not be considered significant. If zeros are: Zeros following a non-zero digit (also called TERMINAL ZEROS) are NOT SIGNIFICANT. So a number like 4000 contains 1 SF. www.upcatreview.com
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9. Chemistry Item 01-06 Now, applying these rules to the given choices: A. 14.00 4 SF - the zeros at the right of a decimal point and non-zero digit are significant. www.upcatreview.com
10. Chemistry Item 01-06 Now, applying these rules to the given choices: B. 00014 2 SF - all the zeros in this number are not significant. www.upcatreview.com
11. Chemistry Item 01-06 Now, applying these rules to the given choices: C. 0.0140 3 SF - the last zero is considered significant since it is at the right of a decimal point and a non-zero digit www.upcatreview.com
12. Chemistry Item 01-06 Now, applying these rules to the given choices: D. 140.0 4 SF - the zeros are all significant (right of a decimal point and non-zero digit) www.upcatreview.com
13. Chemistry Item 01-06 Thus the number with only 2 significant digits is 0.00014 ( letter B ) . www.upcatreview.com