Remark: foils with „black background“ could be skipped, they are aimed to the more advanced courses
Rudolf Žitný, Ústav procesní a zpracovatelské techniky ČVUT FS 2016
General information about course, Basic notions-quantities
This course is approximately at this level
CHEMISTRY E182019 CH1
• Lectures Prof.Ing.Rudolf Žitný, CSc. (Tuesday 10:45)• Tutorials Ing. Jaromír Štancl, PhD. (Tuesday 9:00) • Evaluation (questions and written example max. 30 points)
A B C D E F
27+ 24+ 21+ 18+ 15+ ..14
Summary: General chemistry from the point of view of mechanical and process engineering. Physical chemistry forms 2/3 of the course (structure and properties of matter, thermodynamics, phase equilibrium, chemical reactions, reaction engineering), the remaining 1/3 is devoted to organic chemistry (hydrocarbons, polymers) and biochemistry. Laboratory practice is oriented upon the material properties measurement.
CHEMISTRY E182019 2+1
(Lectures+Tutorials), Classified assesment, 3 credits, Tuesday 10:45, room 312
CH1
http://www.fsid.cvut.cz/~zitnyrud/
excellent very good good satisfactory sufficient failed
CHEMISTRY E182019 CH1
First lecture 4.10.2016 Room 312
LITERATURE• Textbook: Žitný R., Krysa J.: Chemistry, ČVUT Praha, 2000
• Books: Malone L.J.: Basic concepts of chemistry. J.Wiley&Sons, N.Y., 1994Bloomfield M.M.:Chemistry and living organisms. J.Wiley&Sons, N.Y., 1992Moran M.J., Shapiro H.N.: Fundamentals of Engineering Thermodynamics,
J.Wiley&Sons, N.Y., 1992
• Database of scientific articles: You (students of CTU) have direct access to full texts of thousands of papers,
available at
https://dialog.cvut.cz
Jméno DUPS
CH1
DATABASE selection CH1
You can find out qualification of your teacher (the things he is really doing and what he knows)
The most important journals for technology (full texts if pdf format)
SCIENCE DIRECT CH1
Specify topic by keywords (in a similar way like in google)
Title of paper is usually sufficient guide for selection.
CH1 CHEMISTRY Principal subject of this course (important for mechanical engineers)
Only 3 lectures will be delivered
CH1 CHEMISTRY Why chemistry for mechanical engineers? Typical examples
Combustion and chemical reactors (example reactor for steam reforming)
Processing and properties of plasts
CH1 CHEMISTRY Why chemistry for mechanical engineers? Typical examples
Microbial activity in a transported food E.Coli
Salmonella
0 1 0 2 0 t im e [d ]
0 1 0 2 0 t im e [d ]
c fu /g1 0 0 0 1 0 0 1 0 1
T [ 0 C ] 2 0 1 5 1 0 5 0
S a lm o n e lla
S a la d (F E M m e sh )S a lm ons .r .o .
T IN Y T A L K IE
T
t la g p h a s e
CH1 Properties of matterPhysical properties (intensive) T,p,v,u,s,h,… usually lower case letters
Physical quantities (extensive) U, S, H, … usually capitals
Rules of nomenclature
A) Symbols are usually derived from english words (t for time, T for temperature, m for mass, L for length, V for volume, p for pressure, c for capacity or concentration). Exceptions: U-internal energy, H-enthalpy, S-entropy, G-Gibbs energy, Q-heat.
B) If there exists a pair (intensive/extensive) we use CAPITALs for extensive parameter (V-volume, v-specific volume, H-enthalpy, h-specific enthalpy,…)
C) If a property is related to unit mass, use the word SPECIFIC (e.g. v-specific volume, c-specific heat capacity, u-specific internal energy, s-specific entropy, g-specific Gibbs energy of 1 kg)
D) If a property is related to number of particles, use the word MOLAR and lowercase with tilda. As a unit of number of particles is 1 mole (Avogadro’s number) = 6.022.1023. molar internal energy, molar volume and molar enthalpy.
CH1 UNITS - conversion Units SI (Standard International) kg/m/s/K, English lb,ft,0Fmass m kg 1 lb=0.4536 kgmolar mass M kg/kmollength L m 1 ft=0.3048 m 1 in=0.0254 mtemperature T K,oC oF=1.8 oC+32, K=C+273.15internal energy U J 1 BTU=1055.056 J 1 cal=4.186 J enthalpy H Jentropy S J/K
specific volume v m3/kgforce F(=m.a) N(=kg.m/s2) 1 lbf=0.4536∙9.81=4.448222 Npressure p(=F/m2) Pa(=N/m2) 1 bar=105Pa 1 mm Hg=133.22 Pa
1 psi=6895 Padensity (=1/v) kg/m3
Prefixesk kilom milli 10-3
μ micro 10-6 red cell 10 mn nano 10-9 macromoleculesp pico 10-12 atomic radius measured in pm
CH1 PREFIXES - relax
TERA = 1012 PICO = 10-12
GIGA = 109 NANO = 10-9
Given Convert toDensity of Titanium SI units
Density of air 1.2 kg.m-3 Pounds and feet
=1.2(1/0.4536)lb((1/0.3048)ft)-3=1.2/0.45360.30483 lbft-3=0.0749 lbft-3
Atmospheric pressure
1 bar = 105 Pa =
PSI (pound per square inch)
= 105 (1/6895 psi)=14.5 psi
1 lbf (pound-force) SI units (Newton)
lbf=m.g=0.4536 kg 9.81 m/s2 = 4.45 N
PSI is derived unit
1 PSI
Pascals (SI unit)
1 Psi=1 lbf(1 in)-2 =4.4482N(0.0254m)-2=6895 Pa
Boiling point of water is 1000C Degree of Fahrenheit
=1001.8 +32 =212 F
Enthalpy of evaporation of water
2400 kJkg-1=2.4106 J kg-1
BTU (British Thermal Units)
=2.4106(1/1054) BTU((1/0.4536) lb)-1=1033 BTUlb-1
332
3
34401
)10(
10401.4401.4
m
kg
m
kg
cm
g
CH1 Examples-conversion
3401.4
cm
g
Please remember at least density of air (1.2), atmospheric pressure (1 Bar) and enthalpy of evaporation of water (2.4 MJ/kg)
CH1 Examples-unit consistency
pdvduTds
KKkg
J
kg
J 32
Pam
J
m
N
kg
m3
vT T
p
v
s)( )(
Km
J
kg
m
Kkg
J
33
. Km
J
K
Pa3
RT v~p
3m
JPa K
Kmol
J
mol
m3
You do not know (probably) meaning of the following equations. But you can check their corectness by checking units (dimensions of any term must be the same)
It is highly recommended to check in this way any equation or correlation used in your calculations. This is the most effective techniques of errors localisation.
For interested reader: the first equation is the first law of thermodynamic in terms of entropy, the second is Maxwell equation and the last one is state equation of ideal gas. These equations will be discussed in more details later in this course.
CH1 Avogadro’s number Chemistry describes matter at the molecular level. Because amount of atoms/molecules in analyzed samples is extremely large, it is useful to use a new unit for counting tiny elements (atoms, electrons, molecules,…)
mole = 6.02 x 1023 (Avogadro's number)
Avogadro's number is the number of atoms in 12 grams of pure carbon 12C (the upper index 12 identifies the prevailing isotope of carbon).
Statement that in a reactor are 2 moles of O2 means that there are 12.1023 molecules of oxygen (or 4 moles of atoms O).
There are 6.1023 of atoms in 1.008 grams of pure hydrogen. Using this we can conclude, that the mass of one atom of 12C is approximately 12 times greater than the mass of one atom of hydrogen. For other
elements the relative masses are presented in the Periodic Table of the Elements.
Examples of atomic masses (H-hydrogen, C-carbon, N-nitrogen, O-oxygen, Na-sodium, S-sulphur, Cl-chlorine
MH=1.008 g/mole, MC=12.011 g/mole, MN=14.007 g/mole, MO=15.999 g/mole, MNa=22.990 g/mole, MS=32.066 g/mole, MCl=35.453 g/mole.
This value is little bit greater than 12. The reason is that the value 12.011 corresponds to the mixture of carbon isotopes encountered in nature (atomic mass 12 holds only for the pure carbon 12)
CH1 Atomic mass - example
Let us demonstrate, how the atomic mass of titanium (Ti) can be evaluated, given:
• Measured density of solid titanium cube =4.4 g/cm3
• Size of cell (edge in the crystal lattice) measured by X-ray technique L=330.6 pm
Solution:
Titanium crystal lattice is of the type Body Centered Lattice (BCC) looking like this
L 1 cm
How many atoms are in one cell?
Answer nc=2 (see Figure, not 9, think about it)
How many atoms are in cube having side 1cm?
Answer N=nc/L3/106 (106 is conversion 1m =100cm)
How many moles of atoms are in the cube?
Answer n=N/6.02.1023
Atomic mass of titanium
Answer MTi=/n [g/mol]
Final formula (and even than use a pocket calculator)
g/mol 86.472
)106.330(4.41002.61002.6 31229329
cTi n
LM
periodic table Ti 47.87
atomic mass
CH1 ISOTOPES – atomic structure
Electron2H
Neutron
Proton
Electron3H
Neutron
Proton
Electron1H
Proton
There exist different isotopes of almost any element, characterized by the same number of protons (positively charged particles in nucleus), the same number number of negatively charged electrons (at orbits), but different number of neutral nucleus particles – neutrons. Neutron has approximately the same mass as proton (and mass of electrons is almost negligible).
Example is hydrogen Deuterium Tritium
A - Mass number (protons+neutrons)
Z - Atomic number (protons=electrons) 6
12C
CH1 Historical remark - atomDalton – law of multiple proportions
Thomson – discovery of electrons 1897 (plum pudding model)
Planck – quantum mechanics 1900
Einstein – photoelectric effect 1905
Rutheford – mass concentrated in nucleus 1909 (planet model)
Bohr – discrete orbitals, distance of electrons proportional to energy 1913
Rutheford – nuclear particles 1918
Schrodinger - equation for wave function 1926
Murray Gell-Mann, Zweig – quarks 1964
CH1 Historical remark - nucleusDiscovery of nucleus is contribution of Rutheford, who interpreted experiments carried out by Geiger. Geiger bombarded a target (gold Au – sheet) by -particles. Almost all particles came through without any changes of motion, but some were bounced back. Rutheford said: “Ridiculous, it is like a 15” shell bounced from a soft tissue”. It was a nucleus, tiny, but with a big concentrated mass, having capacity to bounce back the incoming -particle of a comparable mass.
detectors
source
CH1 summary – atomic structure
Molecules of compounds consist of atoms, which have a nucleus (protons+neutrons) and an electron shell.
Atomic number Z is the number of protons (=number of electrons).
Atomic mass is the mass of protons and neutrons in the nucleus (mass of 1 proton = mass of 1 neutron = 1 amu).
Isotopes are elements with the same atomic number but different atomic mass (a different number of neutrons).
