lOMoARcPSD|64109549
Module I
Monday, January 6, 2025
10:10 AM
Domains of Chemistry
Macroscopic - what you can be seen or sensed directly by human sight
Microscopic - under a microscope or you have to imagine it
Symbolic - specialized language used to represent macroscopic and microscopic domains
what you write, such as equations, formulas, etc.
Measurements
What are the 3 basic parts of a measurement?
A size (a number written in decimal or scientific rotation)
A standard of comparison (a unit)
An indication of uncertainty.
What is the difference between an exact number and an uncertain measurement?
Exact number - derived from counting, uncertain measurement, derived from a measurement other
than counting.
Exact numbers - there is no uncertainty, they are defined or counted.
E.g. a dozen of eggs, 1 foot is exactly 12 inches.
Measurements have inherent uncertainty due to the process.
Results calculated from a measurement are as uncertain as the measurement itself
Determine how many significant figures are in the numbers below:
Significant figures defined: all measured digits in a determination, including the uncertain last digit.
ALL properly measured digits are significant.
Leading zeros are not significant (first)
Captive zeros (in the middle) are significant
Trailing zeros, if there is a decimal they are significant. (last)
Significant zeros in bold
3090
0.008020
1267
55.0 - 3 significant figures
70.607 - 5 significant figures
0.00832407 - 6 significant figures
1300 - 2 significant figures, therefore 1.3 x10 3
1300. - 4 significant figures, therefore 1.300x10 3
1300.00 - 6 significant figures, 1.30000x10 3
Addition or subtraction - round to the same # of decimal places as the least precise value.
Multiplication or division - round to the same # of digits as the least precise value
If less than 5, leave unchanged
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If more than 5, increase to 1
Length: meter (m)
Mass: kilogram (kg)
Substance: mole (mol)
Temperature: kelvin (K) and Celsius (°C)
Time: seconds (s)
Energy: amperes (A)
Lumens: candela (cd)
Density: kg/m3
Volume: m3
Cubic decimeter is a liter and cubic centimeter is a milliliter (CCs)
Density: mass/volume
Equals 11.3 g/cm3 ✓
Copper 1982 density - 8.93 g/cm3
Zinc after 1982 density - 7.13 g/cm3
Penny volume - 0.349 cm3
m=D*V
Before 1982 : 3.11 grams ✓
After 1982: 2.48 grams ✓
V = m/D
Mass = 85 grams
Density = 0.93 g/mL
V = 91.4mL ✓
Scientific notation
1) 0.00000456 = 4.56 x10 -6 ✓
2) 2.63 x 107 = 26300000 ✓
3) 7800000. = 7.8 x10 6
4) 8.26 x 10-5 = 0.0000826 ✓
5) 0.000673 = 6.73 x10 -4 ✓
6) 3.82 x 104 = 38200 ✓
Dimensional analysis (factor label method)
Versatile mathematical approach applied from simple to more complex calculations involving several
different quantities.
The units must be the same as their associated numbers
Units "cancel out"
Conversion factor
Ratio of two equivalent quantities expressed with different measurement units
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Module I
Monday, January 6, 2025
10:10 AM
Domains of Chemistry
Macroscopic - what you can be seen or sensed directly by human sight
Microscopic - under a microscope or you have to imagine it
Symbolic - specialized language used to represent macroscopic and microscopic domains
what you write, such as equations, formulas, etc.
Measurements
What are the 3 basic parts of a measurement?
A size (a number written in decimal or scientific rotation)
A standard of comparison (a unit)
An indication of uncertainty.
What is the difference between an exact number and an uncertain measurement?
Exact number - derived from counting, uncertain measurement, derived from a measurement other
than counting.
Exact numbers - there is no uncertainty, they are defined or counted.
E.g. a dozen of eggs, 1 foot is exactly 12 inches.
Measurements have inherent uncertainty due to the process.
Results calculated from a measurement are as uncertain as the measurement itself
Determine how many significant figures are in the numbers below:
Significant figures defined: all measured digits in a determination, including the uncertain last digit.
ALL properly measured digits are significant.
Leading zeros are not significant (first)
Captive zeros (in the middle) are significant
Trailing zeros, if there is a decimal they are significant. (last)
Significant zeros in bold
3090
0.008020
1267
55.0 - 3 significant figures
70.607 - 5 significant figures
0.00832407 - 6 significant figures
1300 - 2 significant figures, therefore 1.3 x10 3
1300. - 4 significant figures, therefore 1.300x10 3
1300.00 - 6 significant figures, 1.30000x10 3
Addition or subtraction - round to the same # of decimal places as the least precise value.
Multiplication or division - round to the same # of digits as the least precise value
If less than 5, leave unchanged
messages.downloaded_by
, lOMoARcPSD|64109549
If more than 5, increase to 1
Length: meter (m)
Mass: kilogram (kg)
Substance: mole (mol)
Temperature: kelvin (K) and Celsius (°C)
Time: seconds (s)
Energy: amperes (A)
Lumens: candela (cd)
Density: kg/m3
Volume: m3
Cubic decimeter is a liter and cubic centimeter is a milliliter (CCs)
Density: mass/volume
Equals 11.3 g/cm3 ✓
Copper 1982 density - 8.93 g/cm3
Zinc after 1982 density - 7.13 g/cm3
Penny volume - 0.349 cm3
m=D*V
Before 1982 : 3.11 grams ✓
After 1982: 2.48 grams ✓
V = m/D
Mass = 85 grams
Density = 0.93 g/mL
V = 91.4mL ✓
Scientific notation
1) 0.00000456 = 4.56 x10 -6 ✓
2) 2.63 x 107 = 26300000 ✓
3) 7800000. = 7.8 x10 6
4) 8.26 x 10-5 = 0.0000826 ✓
5) 0.000673 = 6.73 x10 -4 ✓
6) 3.82 x 104 = 38200 ✓
Dimensional analysis (factor label method)
Versatile mathematical approach applied from simple to more complex calculations involving several
different quantities.
The units must be the same as their associated numbers
Units "cancel out"
Conversion factor
Ratio of two equivalent quantities expressed with different measurement units
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