Transcript Chapter 1.1: Types of Matter

Classification of Matter
CHART EXAMINING EACH SUBSTANCE OF
AIR.
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Measurement
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Quantitative Science
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Metric prefixes are often used
Must memorize mega to micro
SI Units
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International units accepted in science for certain msmnts.
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Length – SI unit – Instrument
Volume Mass Temperature -
Accuracy - how close a measurements is to an accepted or
true value.
Precision - the ability to reproduce a measurement
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Rules
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All numbers 1-9 are significant.
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Leading zeros are NEVER significant
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Example: 0.00000000000000001
Captive (middle) zeros are always significant
Trailing zeros are only significant when there is
a decimal point.
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Example: 3,456
Example: 3,500 or 0.000025000
Middle zeros always count.
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Example: 405 or 0.030600
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Rules
 Greater
than 5 round value up
 Less than 5 round value down
 If equal to 5, follow naked 5 rule:
 Even
Stevens, the number remains the same
 Odd up, number rounds up
 Example: 2.35000, round to 2 sig figs.
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These are large or small numbers that use a base 10 as a multiplying
factor.
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The number in front of the base 10 must be a number 1-9.
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Putting numbers into scientific notation
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If you make the number smaller than the base 10 exponent gets larger by the
number of places you move the decimal. Vice versa if you make the number
larger (don’t forget sig figs):
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Example: 660,00 =
Example: .00066 =
Taking numbers out of scientific notation
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Example: 1.2 x 102 not 12 x 103
If exponent is negative make the number smaller (decimal to the left)
If exponent is positive make the number larger (decimal to the right)
Calculations
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Multiplying/Dividing
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Plug into calculator directly – base 10’s do not need to be the same
Adding/Subtracting
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Units must be like terms and base 10’s need to be the same
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Multiplying/Dividing: Least amount of sig figs
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Units do not need to be the same
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When dividing variables with exponents subtract the
exponents
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Example: 8 m3/ 2 m5
When multiplying variables with exponents add them
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Example: mi/hr or N*m
Example: 3 km2 x 7 km4
Adding/Subtracting: Least amount of decimal
places
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Units must be like terms
Example Problem: Sig Fig Calculations
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Carry out the following mathematical operations, and
give each result with the correct # of sig figs:
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A. 1.05 x 10-3/ 6.135
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B. 21 – 13.8
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1.71 x 10-4
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C. As part of a lab assignment to determine the value of the
gas constant (R), a student measured the pressure, volume,
and temperature for a sample of gas where R = PV/T. The
following data was obtained: P = 2.560, T = 275.15, V = 8.8.
Calculate the R constant.
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8.4 x 10-2
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Metric Prefixes
Conversion Factor (key)
Conversion Table
Sample problem:
 How
many micro-ounces are in 7.76 mg?
7.76 mg x 1 x 10-3g x
1 mg
x
263 microoz
1kg
x 2.12 lbs x 16 oz x 1microoz =
1 x 103 g x
1 kg
x 1 lb x 1 x 10-6oz
Example: Dimensional Analysis
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The latest model corvette has an engine with a
displacement of 6.20 L. What is the
displacement in units of cubic inches?
6.20 L x
1 ft3 x (12in)3 = 378 in3
28.32 L
(1ft)3
THE THREE MAJOR TEMPERATURE
SCALES.
TK = TC + 273.15
TC = TK – 273.15
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Converting Between Celsius & Fahrenheit
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More complex because both degree sizes and zero
points are different. So two adjustments need to be
made:
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One for the degree size
Since 212*F = 100*C and 32*F = 0*C:
212 – 32 = 180 Fahrenheit degrees = 100 – 0 = 100 Celsius degrees
180*F or 9*F
100*C or 5*C or the reciprocal depending on which way you go.
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And one for the zero point
Since 32*F = 0*C then we subtract 32 to find Celsius
temp and add 32 to find Fahrenheit temp.
TC = (TF – 32*F) 5*C/9*F
TF = TC x 9*F/5*C + 32
Example Problem: Temperature Conersion
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Normal body temperature is 98.6 *F. Convert
this temperature into the Celsius & Kelvin
scales:
66.6*F x 5*C = 37.0*C
9*F
TK = TC + 273.15 = 310.2 K
Properties of Substances
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Observed without changing
the chemical identity of a
substance.
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Melting Point
Freezing point
Density = mass/volume
Solubility =
grams solute/100g water
Color
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Observed only by changing
chemical identity.
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Flammability
Reactivity
Ability to rust or tarnish
Example: Density
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A chemist, trying to identify the main component of a compact
disc cleaning fluid, finds that 25.00 cm3 of the substance has a
mass of 19.625g at 20*C. The following densities (in g/mL) are
given:
chloroform: 1.492
ethanol: 0.789
toluene: 0.867
diethyl ether: 0.714
isopropyl alcohol: 0.785
Which of these is most likely to be the main component of the
disc cleaner?
D = m = 19.625 = 0.7850 g/cm3
V
25.00
Lab Instruments
Lab Techniques
Filtration
 Distillation
 Chromatography
 Spectrophotometry
 STM
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Filtration
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Vacuum Filtration
SALT REMAINS AFTER ALL WATER IS
BOILED OFF.
PAPER CHROMATOGRAPHY
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Chromatography is a
method used to
separate mixtures.
There is a mobile phase
and a stationary phase.
There are many types of
chromatography
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TLC
GC
Gel Electrophoresis
Spectrophotometer
GAS CHROMATOGRAPHY
STM & STM Images of Ni & Cs
MC #1
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A measured mass of an unreactive metal was dropped into a
small graduated cylinder half filled with water. The following
measurements were made.
Mass of metal = 19.611 grams
Volume of water before addition of metal = 12.4 milliliters
Volume of water after addition of metal = 14.9 milliliters
The density of the metal should be reported as
(A) 7.8444 grams per mL
(B) 7.844 grams per mL
(C) 7.84 grams per mL
(D) 7.8 grams per mL
(E) 8 grams per mL
MC #2
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Mass of an empty container = 3.0 grams
Mass of the container plus the solid sample = 25.0
grams
Volume of the solid sample = 11.0 cubic centimeters
The data above was gathered in order to determine
the density of an unknown solid. The density of the
sample should be reported as
(A) 0.5 g/cm3
(B) 0.50 g/cm3
(C) 2.0 g/cm3
(D) 2.00 g/cm3
(E) 2.27 g/cm3
MC #3
Which of the following techniques is most
appropriate for the recovery of solid KNO3 from
an aqueous solution of KNO3?
(A) Paper chromatography
(B) Filtration
(C) Titration
(D) Electrolysis
(E) Evaporation to dryness
FRQ #1
The area of the 48 contiguous states is 3.02 x106
mi2. Assume that these states are completely
flat (no mountains and no valleys). What
volume of water, in liters, would cover these
states with a rainfall of two inches?
FRQ #2
Wire is often sold in pound spools according to
the wire gauge number. That number refers to
the diameter of the wire. How many meters are
in a ten-pound spool of 12-gauge aluminum
wire?
 A 12-gauge wire has a diameter of 0.0808 in.
 Aluminum has a density of 2.70 g/cm3.
 (V=π r2l)
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FRQ #3
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Air is 21% oxygen by volume. Oxygen has a
density of 1.31 g/L. What is the volume, in
liters, of a room that holds enough air to
contain 55 kg of oxygen?
FRQ #4
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54. The solubility of potassium chloride is 37.0 g/100
g water at 30°C. Its solubility at 70°C is 48.3 g/100 g
water.
(a) Calculate the mass of potassium chloride that
dissolves in 48.6 g of water at 30°C.
(b) Calculate the mass of water required to dissolve
52.0 g of potassium chloride at 70°C.
(c) If 30.0 g of KCl were added to 75.0 g of water at
30°C, would it all disappear? If the temperature were
increased to 70°C, would it then all dissolve?
FRQ #5
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A pycnometer is a device used to measure
density. It weighs 20.455 g empty and 31.486
g when filled with water (d = 1.00 g/cm3).
Pieces of an alloy are put into the empty, dry
pycnometer. The mass of the alloy and
pycnometer is 28.695 g. Water is added to the
alloy to exactly fill the pycnometer. The mass of
the pycnometer, water, and alloy is 38.689 g.
What is the density of the alloy?
FRQ #6
Describe a laboratory procedure needed to
carry out each of the following.
 (a) Separate a mixture of powdered solid CaCl2
and CaCO3.
 (b) Determine the concentration of solute in an
aqueous sodium chloride solution and give the
concentration units that your method provides.
 (c) Separate a mixture of two volatile liquids.
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FRQ #7
Answer the following questions that relate to laboratory observations and
procedures..
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(a) An unknown gas is one of three possible gases: nitrogen, hydrogen, or
oxygen. For each of the three possibilities, describe the result when the gas is
tested using a glowing splint (a wooden stick with one end that has been ignited
and extinguished, but still contains hot, glowing, partially burned wood).
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(b) The following three mixtures have been prepared: CaO plus water, SiO2
plus water, and CO2 plus water. For each mixture, predict whether it is basic,
acidic, or neutral. Justify your answers.
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(c) Each of three beakers contains a 0.1 M solution of one of the following
solutes: potassium chloride, silver nitrate, or sodium sulfide. Three beakers are
labeled randomly as solution 1, solution 2, and solution 3. Shown below is a
partially completed table of observations made of the results of combining small
amounts of different pairs of the solutions.
Sol 1
(i)
Write the chemical formula
of the black precipitate.
 (ii)
Describe the expected results of
mixing solution 1 with solution 3.
 (iii)
Identify each of the solutions
1, 2 and 3.
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Sol 2
Sol 3
Sol 1
----------- Black
ppt
-----------
Sol 2
----------- ----------- No rxn
Sol 3
----------- ----------- -----------