Welcome to the
World of
Chemistry
Yale University
Chemistry 113
Lectures:
Prof. Victor S. Batista
Discussions: Dr. Iona Black
Ms. Brooke Rosenzweig
Mr. Robert Snoeberger
REGISTRATION
Chem 113 students have to register their preferences for a
discussion section online as well as in the hard copy card
distributed during the first lecture.
Students will be able to register their section or lab preference
(1, 2, 3) online by following instructions at the Online Course
Information (OCI) website.
Preference selection has opened and will close on Friday, Sept.
7 at 12:30 PM. At that time each instructor will be able to assign
students according to their preferences for sections.
The office staff will upload the section assignments to the Online
Course System (OCS) and students will be able to see their
section on their course registration sheet.
Where’s the Syllabus ?
https://classesv2.yale.edu/portal/
What does Chemistry concern with ?
Chemistry is the foundation of all molecular
sciences
Chemistry provides understanding,
prediction and control of the nature and
behavior of matter
Chemistry is practical and profoundly
philosophical
HOW CAN SUBSTANCES BE MADE ?
HOW DOES MATTER REACT ?!
WHAT MATTER IS ?!!
Chemistry & Matter
• Chemistry explores the MACROSCOPIC world — what
we can see —
• to understand the PARTICULATE world we cannot see.
EXPERIMENTS provide insights into these worlds
beyond what our eyes can actually see!!
Chem 113 students are strongly
encourage to take the lab Chem 116L
Chemistry 116L Fall 2007
Register in Chem 116L online through the OCS
Placement list will be available online on September 7.
Purchase a copy of the lab manual from TYCO (corner of Elm & Broadway), and study
the first ten pages.
Next week we have orientation and Ex. 1. at 1 pm (for both the 12 noon and 1 pm
sections). Everyone should try to attend the orientation on the day they are placed in
Chemistry 116L. Wear shoes !
Any questions? Need additional info? Email Dr. G:
narasimhan.ganapathi@yale.edu
A Chemist’s
View: Exp. I
Macroscopic
Particulate
Symbolic
2 H2(g) + O2 (g) --> 2 H2O(g)
Chemical Properties and
Chemical Change
•Burning hydrogen (H2) in
oxygen (O2) gives H2O.
• Chemical change or
chemical reaction —
transformation of one or
more atoms or molecules
into one or more different
molecules.
Scientific Method
• (1) OBSERVE AND QUESTION about some aspect of the world.
• (2) POSTULATE a tentative explanation (HYPOTHESIS) and
make predictions.
• (3) TEST those predictions against
observations of reproducible events.
• (4) REPEAT steps 2 and 3 until there are no more discrepancies
between predictions and observations.
When consistency is obtained, hypotheses become a
theory (i.e., a coherent set of propositions that explain
a wide class of phenomena.
Types of Observations and
Measurements
• We make QUALITATIVE
observations of reactions —
changes in color and physical
state.
• We also make QUANTITATIVE
MEASUREMENTS, which involve
numbers.
• Use SI units — based on the
metric system
UNITS OF MEASUREMENT
Use SI units — based on the
metric system
Length
Meter, m
Mass
Kilogram, kg
Time
Seconds, s
Temperature
Celsius degrees, ˚C
kelvins, K
Units of Length
• 1 kilometer (km) = ? meters (m)
• 1 meter (m) = ? centimeters (cm)
• 1 centimeter (cm) = ? millimeter (mm)
• 1 nanometer (nm) = 1.0 x 10-9 meter
o
• 1 angstrom (A) = 1.0 x 10-10 meter
O—H distance =
9.4 x 10-11 m
9.4 x 10-9 cm
0.094 nm
o
0.940 A
Temperature Scales
• Fahrenheit
• Celsius
• Kelvin
Anders Celsius
1701-1744
Lord Kelvin
(William Thomson)
1824-1907
Temperature Scales
Fahrenheit
Boiling point 212 ˚F
of water
Celsius
Kelvin
100 ˚C
373 K
100 K
180˚F
Freezing point
of water
100˚C
32˚F
0˚C
273 K
Notice that 1 K degree = 1 degree Celsius
Temperature
Scales
100 oF = 38 oC = 311 K
32 oF = 0 oC = 273 K
oF
oC
K
Conversion Factor:
100 oC degrees per 180 oF degrees
38 oC = (100 oF – 32 oF) * 100 oC / 180 oF
311 K = 273 K + 38 oC * 100 K / 100 oC
Calculations Using
Temperature
• Generally require temp’s in kelvins
• T (K) = t (˚C) + 273.15
• Body temp = 37 ˚C + 273 = 310 K
• Liquid nitrogen = -196 ˚C + 273 = 77 K
Physical
Properties
What are some physical
properties?
• color
• melting and boiling
point
• odor
sodium
Physical properties salt
characterize the identity of
pure substances
Physical Changes
Some physical changes
would be
• boiling of a liquid
• melting of a solid
• dissolving a solid in a
liquid to give a
homogeneous mixture
— a SOLUTION.
Physical changes do not
change the identity of Pure
Substances
Physical properties, cont’d
DENSITY - an important
and useful physical property
Density 
Mercury
mass (g)
volume (cm3)
Platinum
Aluminum
13.6 g/cm3
21.5 g/cm3
2.7 g/cm3
Problem A piece of copper has a mass
of 57.54 g. It is 9.36 cm long, 7.23 cm
wide, and 0.95 mm thick. Calculate
density (g/cm3).
Density 
mass (g)
volume (cm3)
Strategy
1. Get dimensions in common units.
2. Calculate volume in cubic centimeters.
3.
Calculate the density.
SOLUTION
Conversion
factor
1. Get dimensions in common units.
1cm
0.95 mm •
= 0.095 cm
10 mm
2. Calculate volume in cubic centimeters.
(9.36 cm)(7.23 cm)(0.095 cm) = 6.4 cm3
Note only 2 significant figures in the answer!
3.
Calculate the density.
57.54 g
= 9.0 g/ cm3
6.4 cm3
Significant Figures ??!!!
# of digits, starting from the left, with
the first digit different from zero.
(‘Trailing’ zeros don’t count)
Significant Figures
57.54 g
7.23 cm
0.95 mm
0.095 cm
4 significant figures
3 significant figures
2 significant figures
2 significant figures
(zeros to the left of 9 simply
locate the decimal point)
600. g
3 significant figure
8000 kg
1 significant figure
100 cm/m infinte number of significant figures
(defined quantity)
INVERSE PROBLEM: Mercury (Hg) has a
density of 13.6 g/cm3. What is the mass
of 95 mL of Hg in grams? In pounds?
Solve the problem using DIMENSIONAL
ANALYSIS.
PROBLEM: Mercury (Hg) has a density of
13.6 g/cm3. What is the mass of 95 mL of Hg?
First, note that 1
cm3 = 1 mL
Strategy
1. Use density to calc. mass (g) from volume.
2. Convert mass (g) to mass (lb)
Need to know conversion factor
= 454 g / 1 lb
Inverse Problems
PROBLEM: Mercury (Hg) has a density of 13.6
g/cm3. What is the mass of 95 mL of Hg?
1.
Convert volume to mass
13.6 g
3
95 cm •
= 1.3 x 103 g
cm3
2.
Convert mass (g) to mass (lb)
1.3 x 103 g •
1 lb
= 2.8 lb
454 g