units of measurement meter m liter l celsius c. mass is the amount of matter, weight is a measure of...
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SI UnitsPrefix Symbol Scientific
notationFactor Example
Mega M 1 x 106 1,000,000 megagram (Mg)
Kilo k 1 x 103 1,000 kilometer (km)
Hecto h 1 x 102 100 hectoliter (hL)
Deka da or (D) 1 x 101 10 dekagram (Dg)
BASE UNIT 1 x 100 1 meter
Deci d 1 x 10-1 .1 deciliter (dL)
Centi c 1 x 10-2 .01 centimeter (cm)
Milli m 1 x 10-3 .001 milligram (mg)
Micro u 1 x 10-6 .000001 microgram (ug)
Nano n 1 x 10-9 .000000001 nanometer (nm)
Pico p 1 x 10-12 .000000000001 picogram (pg)
PracticeIn each pair below, circle the larger
Millimeter Centimeter
picometer Micrometer
kilogram Hectogram
deciliter millileter
Basic SI UnitsQuantity Base unit
Length meter (m)
Mass gram (g)
Time second (s)
Volume Liter (L)
Temperature Kelvin (K) or Celsius (C)
Amount of substance mole (mol)
Heat & Energy joule (J)
Metric Conversion
1.) 3.45 cm= Dm
king henry Died by drinking chocolate milkK h D base d c m
0.00345
243.52.) 2.435 g= cg
2.35
3.) 23.8 mL= L
4.) 14.8 km= m
5.) 23.5 cg= dg
0.0238
14800
TemperatureUse both the Kelvin and Celsius scale, to convert
Celsius + 273 = Kelvin
Kelvin -273 = Celsius
373 K = °C
20°C = K293
100
Volume: measured in cubic centimeters (cm3) or liters
• 1 liter (L) = 1 cubic decimeter (dm3) = 1000 millileters (mL)• 1 mL= 1 cm3
• Volume can be measure by Length x width x height or the Water Displacement method
Know the relationship between the following volume units…
L = mL = cm3 (or cc in medical lingo) 1 1000 1000
Density
• Is the ratio of mass per unit of volume. How much matter is packed into a given amount of space
• Density = mass ÷ volume
• D= M V
• The Density of a substance stays regardless of the size of the sample. For example: if you cut a block of copper in half, you have decreased both the mass and volume, the ratio of the 2 stays the same. This is called an Intensive Physical Property.
Constant
Example problems:
• A sample of aluminum metal has a mass of 8.4g. The volume of the sample is 3.1 cm3. Calculate the Density of aluminum.
D = M =V
8.4 3.1
=2.7 g/cm3 2 sig figs
Example problems:
• Diamond has a density of 3.26 g/cm3. What is the mass of a diamond that has a volume of 0.350 cm3?
D = 3.26 g/cm3
M = ? V = 0.350 cm3
D = M V
3.26 g/cm3 x 0.350 cm3 = 1.14 g3 sig figs
Example problems:
• What is the volume of a sample of liquid mercury that has a mass of 76.2 g, given that the density of mercury is 13.6 g/mL?
V = ? M = 76.2 g D = 13.6 g/mL
D= MV
76.2 g 13.3 g/mL = 5.7293 mL = 5.73 mL
Reliable Measurements
• refers to the closeness of the measure value is to the , or real, value.
• refers to how a series of measurements are to one another.
Accuracy
Actual
Precision Close
Example
• An experiment finds the density of lead to be 10.95 g/cm3. The literature value for the density of lead is 13.34 g/cm3.
The error: accepted value – experimental value=
• 13.34 – 10.95 =
An experiment finds the density of lead to be 10.95 g/cm3. The literature value for the density of lead is 13.34 g/cm3.
2.39
The error: accepted value – experimental value=• 13.34 – 10.95 = 2.39
The % error: error x 100 % = accepted value
2.39 x 100 % =13.34
17.9 %
Practice
• Sara’s lab shows the atomic mass of aluminum to be 28.9. What is her percent error if the accepted value is 27.0?
28.9 – 27.0 = 1.90
7.04%1.90/27.0 x 100% =