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BMC seminar 1.
Introduction to general chemistry
The SI system of measurement.
Elements. Symbols for the elements.
Atoms. The structure of atoms. Nuclear arithmetic.
Molecules and ions, compounds and mixtures
Express the following numbers in scientific notation.
Give the significant numbers in each case.
Significant numbers
124556500000 = 1.245565 x 1011
7-12
0.0000005456
= 5.456 x 10-7
4
115
= 1.15 x 102
3
4568020
= 4.56802 x 106
6-7
0.0000789
= 7.89 x 10-5
3
0.01457
= 1.457 x 10-2
4
0.7890
= 7.890 x 10-1
4
The SI system of measurement.
List the fundamental SI units of measure.
What SI prefixes correspond to the following multipliers?
106
mega, M
10-12
pico, p
10-1
deci, d
10-6
micro, μ
101
deka, da
Give the symbol and multipliers for the following prefixes.
Symbol, factor
• kilo
k, 103
• nano
n, 10-9
• milli
m, 10-3
• centi
c, 10-2
• femto
f, 10-15
Mass
Make each of the following conversions.
0.05 μg = ___mg = ___ ng
1 μg = 10-6 g
1 mg = 10-3 g
1 ng = 10-9 g
1 g = 103 mg
1 g = 109 ng
0.05 μg = 5x10-8 g
0.05 μg = 5x10-8 g = 5x10-8 x 103 mg = 5x10-5mg
0.05 μg = 5x10-8 g = 5x10-8 x 109 ng = 5x101ng = 50 ng
Lenght
Make each of the following conversions.
5 pm = ___cm = ___ nm
1 pm = 10-12 m
1 cm = 10-2 m
1 nm = 10-9 m
1 m = 102 cm
1 m = 109 nm
5 pm = 5x10-12 m
5 pm = 5x10-12 m =5x10-12 x102 cm = 5x10-10cm
5 pm = 5x10-12 m =5x10-12 x109 nm = 5x10-3nm
Temperature
Make each of the following conversions:
305 K to oC
305-273 = 32 oC
45 oC to K
45+273 = 318 K
List some derived units.
Make each of the following conversions:
1 dm3 =
1 L
1 dm3 = 1∙10-3 m3
1 cm3 =
1 mL
1 cm3 = 1∙10-3 L
1 cm3 =
1∙103 μL
Make the following conversions:
67 cm3 = ___ m3 = ___ mm3
1 cm = 10-2 m = 101 mm
1 cm3 = 1 cmx1cmx1cm=10-2mx10-2m x10-2m =10-6m3
1 cm3 = 103 mm3
67 cm3 = 67x10-6 m3 = 6.7 x10-5 m3
67 cm3 = 67x103 mm3 = 6.7 x104 mm3
Volume
Density
What is the density of the element copper (in grams per cubic
centimeter) if a sample weighing 324.5 g has a volume of 36.2 cm3?
What is the mass in grams of a 19 cm3 piece of lead? The
density of lead is 11.3 g/cm3.
Mass = density x volume
Mass = 11.3 g/cm3x 19 cm3 = 214.7 g
Energy
Definition: the capacity to supply heat or do work.
Kinetic energy: the energy of motion. EK 
1 2
mv
2
Potential energy: stored energy or energy of position
m2
Unit of energy: 1J  kg  2
s
E p  mgh
Carry out the following conversions.
• 3.5x 10-3 m to pm
3.5 x 109pm
• -25C to K
248 K
• 12 l to cm3
0.012 cm3
• 53 mg to kg
5.3 x 10-5 kg
• 200 Pa to MPa
2 x 10-4 MPa
• 0.5 hour to s
1800 s
• 1.5 g/cm3 to kg/m3
1.5 x 103 kg/m3
Properties of matter
Give the type (extensive/intensive; quantitative/qualitative) for
the following physical properties:
•
•
•
•
•
•
•
•
•
•
Volume
Intensive
Temperature
• Temperature
Color
• Color
Density
• Density
Mass
• Boiling point
Boiling point
• Physical state
Length
Physical
state
• Independent
of size
Area
Heat
Extensive
Mass
Volume
Heat
Length
Area
Dependent of size
Give the definition for physical and chemical properties.
• Physical properties: characteristics of a material which may be
determined without altering the composition of the material; boiling
point, melting point, color, density etc.
• Chemical properties: characteristics of a material which involves
altering the composition of the material; the ability to form new
substances by decomposition or reactions with other substances.
Classify the following properties as physical or chemical property.
A. color
physical
B. boiling point physical
C. rusting
chemical
D. flammability
chemical
E. solubility
physical
Classification of matter
Element
• consists of only one kind of atom
•cannot be broken down into any simpler type of matter by either physical or
chemical means
•can exist as either atoms (e.g. argon) or molecules (e.g., nitrogen).
Compounds
•consists of atoms of two or more different elements bound together
•can be broken down into a simpler type of matter (elements) by chemical means (but
not by physical means)
•has properties that are different from its component elements
•always contains the same ratio of its component atoms.
Mixtures
•consists of two or more different elements and/or compounds physically
intermingled
•can be separated into its components by physical means
•often retains many of the properties of its components.
Classify the following substances as element, compound or
mixture.
A. iron
element
B. ice
compound
C. concrete
mixture
D. tomato juice mixture
E. table salt
compound
mixture of two
elements
an element
a compound
Chemical Symbols
 an abbreviation for the element
 one or two letters; the first Letter is ALWAYS capitalized. The second letter (if any) is
lowercase.
Give the chemical symbol for each of the following elements.
A. Fluorine
F
B. Manganese
Mn
C. Sodium
Na
D. Cobalt
Co
E. Iron
Fe
Give the English name of the elements.
A. C
Carbon
B. N
Nitrogen
C. S
Sulphur
D. Hg
Mercury
E. Ag
Silver
Where can you find the following groups in the perodic table?
A.
B.
C.
D.
Alkali metals
Noble gases
Halogens
Actinides
Properties of metals and nonmetals
Color:
Malleability:
Conductivity:
Melting point:
Metals
Nonmetals
•Silvery shine
•Malleable
•Good conductors of
heat and electricity
•Melt at high
temperature
•Brightly colored
•brittle
•poor conductor, good
insulator
•low melting point
Semimetals
•Silvery in apperance
•Brittle
•Poor conductors,
semiconductors
Identify the following elements as metals, nonmetals or semimetals.
Mg
metal
Sr
Br
metal
nonmetal
Si
semimetal
Ag
metal
S
nonmetal
Atoms. The structure of atoms. Nuclear arithmetics.
Elements are made of tiny particles called atoms.
What is an atom?
How is it put together?
What are the parts of an atom?
Atoms: the smallest component of an element
which carries the chemical characteristics.
Composed of a nucleus surrounded by
electrons. An atom contains specific number
of protons, neutrons, and electrons.
Atomic Numbers and Mass Numbers
Atomic number (Z) = number of protons in the nucleus.
Mass number (A) = total number of protons and neutrons in the nucleus.
Fill in the following table for each of the species below:
12
6
C
19
9
F
24
2
12 Mg
A
Z
N
Number of
electrons
12
6
6
6
0
Symbol
Electrical
charge
19
9
10
9
0
24
12
12
10
+2
Give the symbol of the element with the mass number 39 and
20 neutron.
A=Z+N
Z = A – N = 39-20 = 19
→K
Isotopes
Isotopes have the same Z but different A.
Chlorine has two main isotopes, with neutron numbers 18 and 20. Look up the
atomic number of chlorine, tell how many neutrons each isotope contains, and
give the standard symbol for each.
35
17
Cl
37
17
Cl
Atomic mass
Atomic mass unit or Dalton
Protons and neutrons each have a mass of almost exactly 1 amu.
The mass of an atom in amu ≈ the atom's mass number.
Atomic mass of an element
35Cl
isotope has a mass of 35 amu and is 75.8% abundant.
37Cl isotope has a mass of 37 amu and is 24.2% abundant.
Average atomic mass =
(Fraction abundance of isotope 1) x (mass of isotope 1) +
(Fraction abundance of isotope 2) x (mass of isotope 2)
Average atomic mass of Cl = (0.758)(35 amu) + (0.242)(37 amu)
= 35.45 amu
Copper metal has two naturally occuring isotopes: copper-63 (69.17%;
isotopic mass = 62.94 amu) and copper-65 (30.83%; isotopic mass = 64.93
amu). Calculate the atomic mass of copper and check the answer in the
periodic table.
63
29
Cu
65
29
Cu
isotope has a mass of 62.94 amu and is 69.17% abundant.
isotope has a mass of 64.93 amu and is 30.83% abundant.
Average atomic mass of Cu =
(0.6917)(62.94 amu) + (0.3083)(64.93 amu) = 63.55 amu
Molecules
– Distinct packages of atoms bound together
by sharing electrons (covalent bonds)
– can be same element or different elements
(O2, HCl,C12H22O11,...)
– must be neutral (no charge)
– nonmetal with nonmetal
• Diatomic elements
Ions
- form by tranfer of electrons
- ionic bond generally forms between a
nonmetal and a metal
- ionic solid: cations and anions are
packed together in a regular way
Cl
+ e-
Cl-
Na+
Cl-
Na
Na+ + e-
Which of the following compounds would you expect to be ionic and which
molecular?
A.
B.
C.
D.
E.
F.
G.
H.
CH4
water
CaF2
BrCl
KCl
H2S
CH3CH2OH
NaOH
molecular
molecular
ionic
molecular
ionic
molecular
molecular
ionic
Which of the following drawings is most likely to represent an
ionic compound, and which a molecular compound?
ionic
molecular