unit 1- chemical foundations-1 gg
TRANSCRIPT
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 1/25
Chapter 1- Matter and Change
Chapter 2- Measurements and Calculations
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 2/25
I. Matter- anything that takes up space and has
mass.
A. Properties and Changes in Matter
1. P
hysical property- an characteristicobserved w/out changing the identity of
the substance (melting pt, color, temp«)
a. Physical change- a change in a substancethat does not involve a change in the identity
(cutting, melting, boiling«)
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 3/25
2. Chemical property- relates to a
substance¶s ability to undergo changesthat transform it to a different substance.
a. Chemical change- a change in which one
or more substances are converted intodifferent substances.
Reactants products
Na+ + Cl- NaCl
yields
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 4/25
3. Extensive (Quantitative) Properties-
depend on the amount of matter .
a. Mass- the amount of matter an object contains.
b. Weight- the gravitational pull on an object.
c. Volume- the space something takes up.
4. Intensive (Qualitative) Properties- do not
depend on the amount of matter .
a. Density- the ratio of an objects
mass to its volume.
a. Melting/boiling point- the temp.
at which a substance melts/boils.
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 5/25
II. Classification of Matter
Matter
Can it be separated?
Mixtures Pure Substances
Is the composition
uniform?
Can it be decomposed by
ordinary chemical means?
Homogenous
Mixtures(air, sugar in water)
Heterogeneous
Mixtures(granite, blood)
Compounds(water, sugar)
Elements(oxygen, sodium)
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 6/25
II. Classification of Matter
A. Mixtures- consist of a physical blend of twoor more substances of variable
composition.
1. Types of Mixtures
a. Homogenous- the same throughout
(milk, saline solution«) b. Heterogenous- not the same throughout
(pizza, sand and water).
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 7/25
B. Pure Substances- consist of a fixed
composition.
1. Elements- the simplest form of matter
(Periodic Table).
a. Chemical symbols- shorthand for the
element on periodic table.
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 8/25
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 9/25
III. The Scientific Method- incorporates observations, hypotheses,
ex periments, theories and laws.
A. Stages in the Scientific Method
1. Observing/collecting data
2. Formulating hypotheses
3. Testing hypotheses
4. Collecting data
5. Theorizing
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 10/25
B. Collecting data
1. Observations- the noting and recording
of facts.
2. Inference- an
interpretation of an
observation.
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 11/25
IV. Units of Measurement
A. SI system- a standard system of scientificmeasurement.
1.
The 7 Fundamental SI
Units
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 12/25
2. Derived SI Units- produced by
multiplying or dividing SI units.
a. Volume- V = L x W x H
= cm x cm x cm
= cm3
1 cm3 = mL
b. Density- D = mass/ volume
= g/cm3
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 13/25
V. Using Scientific Measurements
A. Accuracy vs. Precision
1. Accuracy- how close a measurement
comes to the actual true value.
2. Precision- the reproducibility of the
measurement.
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 14/25
B. Percent Error- the accuracy of an average
ex perimental value compared to theaccepted value.
Percent Error = Valueex p.
± Valueacc.
x 100
Value acc.
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 15/25
VI. Developing Tools For Analysis
A. Making Tables and Graphs- graphs visuallyshow proportional relationships among
data.
1. Slope = y2 - y1
x2 - x1
= (y( x
= rise
run
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 16/25
B. Rules for Good Graphing
1. Give your graph a descriptive title.
2. Indent the axes from the edge of the
graph paper .
3. Label each axis and the units used.
4. Choose an appropriate scale.
5. Choose a convenient scale.
6. Locate points with a small circle around
them.
7. Draw a smooth curve or straight line to
represent the general tendency of the
data points.
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 17/25
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 18/25
VII. Significant Figures
A.Significant Figures- all thedigits in a measurement that can be
known accurately plus a last
digit that must be estimated.
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 19/25
1. Which digits are significant?
a. Every nonzero digit in a measurement.
b. Zeros appearing between nonzero digits.
c. Zeros at the end of a number and to the
right of a decimal point.
d. Zeros at the end of a measurement only if the number contains a decimal point.
e. All digits in scientific notation.
f . Zeros appearing in front of all nonzero
digits are NOT significant.
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 20/25
VIII. Significant Figures in Measurement
A.No measurement is e
xact!
1. It is important to state ex perimental
results with a number of significant
digits which give a reasonableimpression of the accuracy of the
measurement.
Consider an example of a measured density.
Suppose you measured the mass of a rock to be
9.3 grams and it¶s volume to be 3.4 cm3.
Density = mass = 9.3 g = 2.44736 g/cm3
volume 3.8 cm3
Mass measured
to 2 SF¶sVol. measured to
2 SFs
Not science but fiction!Maybe this doesn¶t look as impressive but it is a better answer
= 9.3 g = 2.4 g/cm3
3.8 cm3
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 21/25
B. Multiplying and dividing
1. The measurement with the fewest
significant figures determines the
number of significant figures in the
answer .
4.28 m x 9.2567 m = 3.96 m2
0.62 cm x 1.56 cm = 0.97 cm2
985.33 g / 65.2 mL = 15.1 g/mL
27.30 L2 / 2.73 L = 10.0 L or
1.00 x 101 L
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 22/25
C. Adding and subtracting
1. The measurement with the digit
having the lowest decimal value
determines the decimal value in the
answer .
12.1 g + 435.673 g = 447.8 g
62 m - 25.321m = 37 m
1.20 mL - .0021 mL = 1.20 mL
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 23/25
IX. Dimensional Analysis (Unit-Factor Method)
A. Dimensional Analysis- the converting of
unit into another without changing the
value of the original amount.
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 24/25
1. Conversion Factors - shows the
relationship between two measurements.
a. A ratio where the measurement on the
top is equal to the measurement on the
bottom.
100 cm = 1 & 1 m_ = 1
1 m 100 cm
8/8/2019 Unit 1- Chemical Foundations-1 Gg
http://slidepdf.com/reader/full/unit-1-chemical-foundations-1-gg 25/25
2. Steps in Dimensional Analysis
(1)W
rite down what is given(2) Create an equality between what is
given and what you want to change to.
(3) Set up a conversion factor (the unit to
cancel goes on the bottom)(4) Do math. Multiply tops, divide by
bottoms.
HOW MANY CM IN 6.4 INCHES?
6.4 INCHES 2.54 CM =
1 INCH
Correct
for SFs!
16.3 CM
16.256 CM