userdata-paziras-Chem101-Chap_01B

63cm heighth614cm 3 v p r2 h p 063cm2 614cm7655954cm

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Unformatted text preview: SIGNIFICANT FIGURES IN CALCULATIONS · THE ANSWER TO A CALCULATION CAN HAVE NO MORE SIG FIGS THAN THE LEAST ACCURATE NUMBER (LAN) Multiplication and Division LAN = number with the fewest SIG FIGS Example 1: Calculate the volume of a cylinder, given: Radius (r) = 0.63 cm Height (h) = 6.14 cm 3 V = p r2 h = p (0.63 cm)2 (6.14 cm) = 7.655954 cm 2 SF 3 SF calculator answer LAN · Note: The answer can have no more than 2 SF 3 · The correct answer is : 7.7 cm Example 2: Calculate the density of a liquid, given: Mass (m) = 10.9387 g Volume (V) = 10.00 mL 6 SF ¯ d = 10.9837 g = 1.09387 g/mL (calculator answer) 10.00 mL - 4 SF (LAN) · Note: The answer can have no more than 4 SF · The correct answer is : 1.094 g/mL 13 Chemistry 101 Chapter 1 Addition and Subtraction LAN = number with the fewest decimals Example 3: Add the following measurements: 212. 2.1 1.88 _______ 215.98 g g g ( 0 decimals) ¾¾¾¾¾¾> LAN (1 decimal) (2 decimals) g <¾¾¾¾¾ calculator answer · Note: The answer can have no more decimals than the LAN (0 decimals) · The correct answer is: 216 g Example 4: Subtract the following measurements: 1.0947 g – 1.093 g (3 decimals) ¾¾¾¾¾¾> LAN ________ 0.0017 g <¾¾¾¾¾ (calculator answer) · Note: The answer can have no more decimals than the LAN (3 decimals) · The correct answer is: 0.002 g 14 Chemistry 101 Chapter 1 Combined Calculations Example 5: Given the following values, calculate the percent error in this measurement: Theoretical Value = Experimental Value = % Erro r = 1.0943 g 1.0947 g ? 1 SF (LAN) Exp ­ Th 1.0947 ­ 1.0943 0.0004 g % Error = x100 = x 100 = x100 = 0.036553 % (calculater answer) Th 1.0943 1.0943 g (5 SF) · Note: The correct answer cannot have more than 1 SF · THE CORRECT ANSWER IS : 0.04 % Example 6: Given the following values, calculate the percent error in this measurement: Theoretical Value = Experimental Value = % Erro r = % Error = 3 2.70 g/cm 3 3.09 g/cm ? Exp ­ T h x100 = Th x 100 = · Note: The correct answer cannot have mo...
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