3.2. Unit Conversions, Error, and Uncertainty http://www.ck12.org
- Density is typically reported in terms of grams/mL (g/mL) or grams per cubic centimeter (g/cm^3 ).
- If a solid is irregularly shaped, we can determine its volume by measuring the volume of water that the solid
displaces. - There are three temperature scales that are commonly used. Their units are °F (degrees Fahrenheit), °C
(degrees Celsius), and K (Kelvin).
Lesson Review Questions
Make an estimate of the length that is shown inFigure3.9 and use this information to answer the following questions.
FIGURE 3.9
- If the length inFigure3.9 were estimated to be 11.65 cm±0.05, what would be the range of values that fall
within the acceptable uncertainty for this instrument? - Which of the following length estimates would be accurate forFigure3.9?
(a) 11.59
(b) 11.71
(c) 11.64
(d) 12 - Which of the following length estimates would be precise for theFigure3.9?
(a) 11.64, 11.65, 11.65
(b) 11.60. 11.56, 11.45
(c) 10.9, 12.2, 12
(d) 11, 11.23, 11.234 - A student measures the density of gold and finds it to be 18.3 g/mL. The accepted value from the Handbook
of Chemistry and Physics is 19.3 g/mL (Lide 1992-1993). What is the percent error of the student’s results? - How would you report 40.889 m^3 to three significant figures using scientific notation?
- Complete theTable3.7.
TABLE3.7:
°F °C K
A 57
B 37
C -40- What is the average mass of three objects whose individual masses are 10.3 g, 9.334 g, and 9.25 g?