Download presentation
Presentation is loading. Please wait.
Published byFrederick Wilcock Modified over 9 years ago
1
Measurements with Range Uncertainty CHEMISTRY 11 UNIT 1.3
2
250 mL Erlenmeyer Flask - LIQUID Read volume from eye level, bottom of meniscus Class values (mL): 112.5, 150, 151, 153, 154, 155, 157, 158, 160, 162, 175
3
50 mL Erlenmeyer flask - LIQUID Read volume from eye level, bottom of meniscus Class values (mL): 15, 17, 25, 27, 28, 29, 30, 31
4
400 mL beaker - LIQUID Read volume from eye level, bottom of meniscus Class values (mL): 115, 120, 155, 170, 172, 175, 178, 182, 185
5
50 mL beaker - LIQUID Read volume from eye level, bottom of meniscus Class values (mL): 15, 16, 17, 18, 27
6
100 mL graduated cylinder - LIQUID Read volume from eye level, bottom of meniscus Class values (mL): 73, 77, 78, 79, 88
7
10 mL graduated cylinder - LIQUID Read volume from eye level, bottom of meniscus Class values (mL): 3.4, 3.5, 3.6, 3.7, 3.9
8
Electronic balance – 10 DIMES Zero/Tare scale before beginning. Read all digits. Class values (g): 1.75, 17.5, 17.6, 17.7
9
Triple -beam balance – 10 DIMES Quadruple Adjust largest mass (100 g increments) first until the right side drops. Move back one increment. Adjust next largest mass (10 g increments) and so one until right side is balanced in line with marker on right side. Record the value starting with hundreds, then tens, then ones.... Class values (g): 7, 7.7, 17.53, 17.57, 17.6, 17.7, 17.8
10
Centimetre ruler – POST-IT NOTE Make sure ruler is parallel to object being measured. Record measurement. Class values (cm): 4.6, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 10
11
Centimetre ruler with millimetre divisions – POST-IT NOTE Make sure ruler is parallel to object being measured. Record measurement. Class values (cm): 3.5, 7, 7.2, 7.3, 7.4
12
Recording Measurements Record all CERTAIN digits from marked lines plus one UNCERTAIN digit (an estimate) Write down your RANGE UNCERTAINTY of +/- one-tenth to one-half of the smallest marked division Okay, let’s try those measurements again!
13
250 mL Erlenmeyer Flask - LIQUID 153 mL +/- 3 mL
14
50 mL Erlenmeyer flask - LIQUID 25 mL +/- 3 mL
15
400 mL beaker - LIQUID 174 mL +/- 5 mL
16
50 mL beaker - LIQUID 13 mL +/- 2 mL
17
100 mL graduated cylinder - LIQUID 77.2 mL +/- 0.2 mL
18
10 mL graduated cylinder - LIQUID 3.42 mL +/- 0.02 mL
19
Electronic balance – 10 DIMES 17.6 g +/- 0.1 g
20
Triple -beam balance – 10 DIMES Quadruple 17.531 g +/- 0.002 g
21
Centimetre ruler – POST-IT NOTE 7.4 cm +/- 0.1 cm
22
Centimetre ruler with millimetre divisions – POST-IT NOTE 7.35 cm +/- 0.02 cm
23
Significant Figures (a.k.a. Significant Digits) You must be able to read a measuring device correctly because of SIGNIFICANT FIGURES: some digits are important because they are likely to be true, we call these SIGNIFICANT FIGURES or SIG FIGS for short Every measuring device has a maximum number of Sig Figs. You cannot use a school centimetre ruler and say that a Post-it Note is 7.35870091 cm wide.
24
Sig Fig examples 45000 2 sig figs 45001 5 sig figs 0.0045 2 sig figs 405 3 sig figs
25
Sig Figs continued Any number that is COUNTED DIRECTLY and NOT MEASURED OR ESTIMATED should not be considered as having Sig Figs. Example: There are 30 students in Ms. Dhir’s Chemistry 11 class. “30” is an exact number, no part of this is an estimate and we do not have any RANGE UNCERTAINTY with it.
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.