Department of Petroleum and Mining General Chemistry Department of Petroleum and Mining First Stage 2018-2019 Wrea Mohammed Ibrahim

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.

Classification of Matter: The basic difference between states of matter is the distance between the “bodies.” Solid – bodies are rigid objects with definite shapes. Liquid – bodies closer together, are less rigid than solids but still able to flow and assume the shape of their containers. Gas – bodies are far apart and in rapid motion. they can expand indefinitely. plasma is a gaseous state of matter that contains appreciable numbers of electrically charged particles.

Plasma

Classification of Matter

Pure substances and Mixtures Pure substance is any matter that has a fixed chemical composition and characteristic properties. Examples are water, ammonia, sugar. Mixture is a combination of two or more substances in variable proportions in which the substances retain their chemical identities. Examples are air, milk, and cement. 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)

Elements and Compounds Element A substance that can not be separated into simpler substances by chemical means. Gold- Au Silver- Ag Tin- Sn 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

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.

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

Matter and Change Melting Physical Change - A physical change involves the conversion of a substance from one state of matter to another, without changing its chemical composition. H2O (s) H2O (l) Melting Point Boiling Point Temperature Density Mass Volume Melting Lecture Notes

Physical Change

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

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

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

Dalton’s atomic theory 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.

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.

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

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

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

Molecular mass or Molecular weight Is the mass of a molecule. It is calculated as the summation 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