University:
Jackson College
Course:
CEM-141 | General Chemistry I
Academic year:

2024
Views:

397

Pages:

2
Author:

Veggianl5om

CHEMISTRY : SIGNIFICANT DIGITS MEASUREMENT PRACTICE I Significant figures are the digits in any measurement that are known with certainty plus one digit that is uncertain. Rule 1: In numbers that do not contain zeros, all the digits are significant. SCIENTIFIC NOTATION B. Convert the following numbers Into or out of scientific notation: RETAINING SIG FIGS 3.1428 [5] 3.14 [3] 469 [3] Rule 2: All zeros between significant digits are significant. 7.053 7053 302 [4] [4] [3] Rule 3: Zeros to the left of the first nonzero digit serve only to fix the position of the decimal point and are not significant. 0.0056 0.0789 0.000001 [1] [2] [3] Rule 4: In a number with digits to the right of a decimal point, zeros to the right of the last nonzero digit are significant. 43 [2] 43.0 430 [2] [3] 43.00 [4] 0.00200 [3] 430. [3] 0.40050 [5] 142.63 1,500,000 1.4263 ×102 1.5 ×106 0.00336 3.36×10-3 1.63 x 107 16300000 3.11 x 10-4 0.000311 0.00125 1.25×10-3 86,400 8.64×104 1.01 x 106 1010000 9.81 x 101 0.000000000000144 98.1 1.44x10-13 4,663,310.56 4,66331056 × 106 ROUNDING GENERAL RULES FOR ROUNDING: 4.676 4.68 XY X When Y 5, increase X by 1 When Y <5, don't change X 4.6724.67 When Y = 5, If X is odd, increase X by 1 4.6754.68 If X is even, don't change X 4.6854.68 Rule 5: in a number that has no decimal point, and that ends in zeros (such as 3600), the zeros at the end may or may not be significant (it is ambiguous). To avoid ambiguity express the number in scientific notation showing in the coefficient the number of significant digits. 3.6 x 103 contains two significant digits A. How many significant digits are in each of the following numbers? C. Round each of the following numbers to four significant digits. 6.16782 6.19648 0.0019872 6,168 6.196 0,001987 3.141x104 213.2 14.16 90210 1837 4 205.8 4 3.14145 x 104 213.25 3.14145 x 104 6 1900 2 14.163000 6005 4 1200.43 6 90210 0.08206 4 6000 234.4 234.4 0.000014 2 632 3 1200.43 149356 14,163000 6 8 0.0022475 1200. 0.002248 8.7300 5 14.000 5 14.16300 14.16 0,00743 3 302400.00 8 0.02315 0.02315 302400 4 0.0019872 5 13.462 13.46 8.732 4 20000 135.69 135.7 14.000 5 426.1 4 152.00 152.0 19.7342 60.0 3 395.55 395.6 9.021×104 1.200x103