1. Department of Petroleum and Mining
General Chemistry
Department of Petroleum and Mining
First Stage
Wrea Mohammed Ibrahim

2. CHEMISTRY: (What is Chemistry?)
Chemistry is the study of the properties, composition, and structure of matter, undergoes the physical and chemical changes, and the energy liberated or absorbed during those changes.
Matter – anything that occupies space and has mass.

3. Classification of Matter:
The basic difference between these states is the distance between the “bodies.”
Gas – bodies are far apart and in rapid motion.
Liquid – bodies closer together, but still able to move past each other.
Solid – bodies are closer still and are now held in place in a definite arrangement.

6. Classification of Matter

7. The Law of Conservation of Matter : Matter is neither created nor destroyed during a chemical reaction or a physical change. ENERGY: Energy is the ability to do work or generate thermal energy.

8. Pure Substances and Mixtures:
Mixture – combination of two or more substances in which each substance retains its own chemical identity.
Homogeneous mixture – composition of this mixture is consistent throughout.
Solution (Air, sugar water)
Heterogeneous mixture – composition of this mixture varies throughout the mixture.
Solution (blood, pizza)

9. Pure Substances and Mixtures
It is also possible for a homogeneous substance to be composed of a single substance – pure substance.
Element – A substance that can not be separated into simpler substances by chemical means.
Compound - A substance composed of two or more elements chemically combined in fixed ratios by mass.
Water - H2O Carbon dioxide - CO2
Sodium Chloride – NaCl Iron(II) sulfide - FeS
Atom – the smallest unit of an element that retains a substances chemical activity.

10. Elements There are 114 elements known.
Each element is given a unique chemical symbol (one or two letters).
Carbon C, Nitrogen N, Titanium Ti
Notice that the two letter symbols are always capital letter then lower case letter because:
CO – carbon and oxygen
Co – element cobalt

11. Classification of Mixtures:
- Homogeneous - A mixture having only one phase; it is uniform (the same) throughout and has the same properties throughout. These are called
Solutions.
- Heterogeneous - A mixture with more than one phase. It is non-uniform and does NOT have the
same properties throughout.
Lecture Notes

12. Matter and Change
Physical Change - A change in which each substance involved in the change retains its original identity and no new elements or compounds are formed. H2O (s) H2O (l) Melting Point Boiling Point Temperature Density Mass Volume
Melting
Lecture Notes

13. Physical Change

14. Chemical Change -A change in which one or more elements or compounds (substances) are formed.
AgNO3 (aq) + HCl (aq) AgCl (s) HNO3 (aq)
“Reacting”
Lecture Notes

15. Properties of Matter
Extensive Properties - Properties that depend on the amount of matter present in a sample.
Mass Volume Heat Capacity
Intensive Properties - Properties that do NOT depend on the amount of matter present in a sample.
Color Temperature Density
Melting Point Specific Heat Boiling Point
Lecture Notes

16. All matter is made up of undividable particles called atoms.
Atoms are completely solid.
Atoms are homogeneous.
Atoms vary in: 1)Size 2) Shape 3) Weight

17. …Dalton’s Research…
1.Chemical elements are made of atoms 2.The atoms of an element are identical in their masses. 3. Atoms of different elements have different masses.

18. The charges of the parts in an atom are shown for a oxygen atom.
Pictures of an atom
The green and red spheres represent the protons and neutrons of the atom. The orange spheres represent the electrons.
The charges of the parts in an atom are shown for a oxygen atom.

19. Key Definitions of Today’s Atom
Proton – positive part of the atom; found in the center of the atom (nucleus) Neutron – neutral (no charge) part of the atom; found in the center of the atom Electron- negative part of the atom; found circling the center of the atom Nucleus – center of the atom; home of the proton and neutron; has the majority of the mass of the atom

20. An ion forms when an atom gains or loses one or more electrons.
Ions:
An ion forms when an atom gains or loses one or more electrons.
positive ions -formed when atoms lose electrons
negative ions -formed when atoms gain electrons

21. Element: A substance composed of only one type of atom (all the atoms have the same number of protons). Elements cannot be broken down into smaller substances. Molecule: A unit composed of two or more atoms joined together by chemical bonds

22. Molecular mass or Molecular weight
Is the mass of a molecule. It is calculated as the sum of the atomic mass of each constituent atom multiplied by the number of atoms of that element in the molecular formula.
Example:- H2O , CO2
M.wt H2O = (2*1 )+(1*16) =18 g/mole
M.wt CO2 = (1*12)+ (2*16)= 44 g/mole