Download Matter and Measurement

Matter and
Measurement
Ch 1 Brown, LeMay
The Basics (1.2 & 1.3)
• States of Matter
•
•
•
•
•
Solid
Liquid
Gas
Plasma
Bose-Einstein Condensate (BEC)
• Particle Spacing
• Particle Movement
• Energy
Classification of Matter
Classification of Matter
Classification of Matter
Classification of Matter
Classification of Matter
Classification of Matter
Classification of Matter
Classification of Matter
Classification of Matter
Properties and Changes of
Matter
Types of Properties
• Physical Properties…
• Can be observed without changing a substance into another
substance.
• Boiling point, density, mass, volume, etc.
• Chemical Properties…
• Can only be observed when a substance is changed into another
substance.
• Flammability, corrosiveness, reactivity with acid, etc.
Types of Properties
• Intensive Properties…
• Are independent of the amount of the substance that is present.
• Density, boiling point, color, etc.
• Extensive Properties…
• Depend upon the amount of the substance present.
• Mass, volume, energy, etc.
Separation of Mixtures
Hand Separation
• Separate a mixture like this…
• …by using your hand!
Filtration
• In filtration solid
substances are
separated from
liquids and solutions.
What remains on the
filter paper is called
the “precipitate”
and what passes
through is called the
“filtrate.”
Separating Funnel
Shake
and let
sit…
Usually used to separate immiscible liquids, like oil
and water mixture.
Centrifuge
Separates particles of different masses based on
centrifugal force. Heavier particles settle at the bottom
followed by the lighter particles on top.
Place in
centrifuge…
Distillation
• Distillation uses
differences in the
boiling points of
substances to separate
a homogeneous
mixture into its
components.
Chromatography
This technique separates substances on the
basis of differences in solubility in a solvent
S.I. – The Metric System (1.4)
Uncertainty
• Precision: how closely individual measurements
agree with one another; the “fineness” of a
measurement
• Accuracy: how closely individual measurements
agree with the “true” value
• Significant Figures: for any measurement, all the
digits that are “certain” plus one “uncertain”
digit, an indication of precision
Determining Significant Figures
• 1. Any nonzero digit is significant.
• 457 cm = 3SF
29cm = 2SF
• 2. Any zero between nonzero digits is significant.
• 1005 kg = 4SF
807 = 3SF
• 3. Any zero in front of a number is not
significant; it’s a placeholder.
• 0.0026 Å = 2SF
0.41 Å = 2SF
Anders Ångström
(1814 – 1874)
Determining Significant Figures
• 4. Any zero at the “end” of a number & there is a
decimal point in the number is significant.
• 0.05000 K = 4SF 3000 K = 1SF 7000.K = 4SF
• 5. For exact numbers (e.g. 4 beakers) & those
used in conversion factors (e.g. 1 inch = 2.54
cm), there is no uncertainty in their
measurement and are considered to have
infinite significant figures.
• For more practice: http://lectureonline.cl.msu.edu/~mmp.applist/sigfig/sig.htm
Calculating with Sig Figs
• 1. Addition & Subtraction: a sum or difference
has the same number of decimal places as the
measurement with the fewest decimal places.
• 15.047 g + 4.12 g = ?
15.047
+ 4.12
19.167
19.17g
• 25,040 mL + 37,200 mL = ?
25,040 mL
+37,200 mL
62,240
62,200mL or 6.22 × 104 mL
Calculating with Sig Figs
2. Multiplication & Division: a product or quotient may be
no more significant than the least significant
measurement. Use the least significant figures.
3.000 × 4.00 = 12.0
(4SF) (3SF)= (3SF)
3. Logarithms: retain in the mantissa (the decimal part of
the logarithm) the same number of Sig Figs there are in the
original value.
log (3.000 × 104) = 4.477121255 = 4.4771
log (3 × 104) = 4.477121255
= 4.5
Calculating with Sig Figs
• 4. Series of Operations: keep all non-significant digits
during any intermediate calculations, and round to the
correct number of significant figures at the end.
(4.5 + 3.50001) × 2.00 = (8.00001) × 2.00 = 16.0002
= 16
Rounding Rules for Significant Figures
• 1. Look at the leftmost digit of the numbers you
are removing, if it is less than 5, don’t round the
last sig fig up.
• Ex. 7.248 rounded to two SF would be 7.2
• 2. If the leftmost digit of the numbers you are
removing is 5 or greater, round the last sif fig up.
• Ex 4.735 rounded to three SF would be 4.74
Dimensional Analysis (1.6)
• Is an aid when solving problems based on cancelling out the
units you don’t need in favor of those you do need.
• Uses conversion factors
• Given unit × desired unit = desired unit
given unit