Upload
ps-nkosi
View
362
Download
0
Tags:
Embed Size (px)
Citation preview
TXSA 111 CHEMISTRY
SEMESTER 1—JANUARY 2013 BY: MR PS NKOSI
SYLLABUS BASIC CONCEPTS ABOUT MATTER. ATOMIC STRUCTURE AND PERIODIC TABLE. CHEMICAL BONDING AND INTERMOLECULAR FORCES. THE MOLE CONCEPT AND BALANCING CHEMICAL
EQUATIONS. SOLUTION. ACIDS AND BASES. OXIDATION AND REDUCTION. INTRODUCTION TO ORGANIC CHEMISTRY. INTRODUCTION TO INORGANIC CHEMISTRY. …….................................................................................................... PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 2
BASIC CONCEPTS ABOUT MATTER CHEMISTRY is the study of matter and the changes it
undergoes. Structure Properties
MATTER is all substances of the universe, living and non-living.
It made up of molecules and atoms. It can be changed from one state to another by
Adding or removing heat Pressurizing
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 3
Matter is usually classified into three classical states of matter, with plasma sometimes added as a fourth state for scientific purposes. From left to right: grains of refined sucrose (a solid), water (a liquid), depiction of particles in a gas, and a plasma globe (plasma).
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 4
The properties of substance can be used in a number of ways: 1. To identify an unknown substance, e.g in chemistry
laboratories, crime labs and medical labs. 2. To distinguish between different substances, e.g.
gold and fake gold. 3. To characterize a newly discovered substance- the
substance is new if it has a unique set of properties. 4. Predicting the usefulness of a substance for specific
applications, e.g carbon monoxide is not used as an atmosphere in space capsules
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 5
PHYSICAL PROPERTIES This are characteristics of matter that can be observed
or measured without altering the chemical composition and identity of the substance. E.g. State, colour, density, melting point, boiling point,
volume, temperature, mass.
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 6
CHEMICAL PROPERTIES This are properties can be observed if a change in
chemical composition and identity of a substance occurs. E.g. Charcoal burns, iron rusts
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 7
CLASSIFY EACH OF THE FOLLOWING AS CHEMICAL OR PHYSICAL a) A substance is very hard. b) A substance melts at 48 degrees. c) A substance is flammable. d) A substance is green in colour. e) A substance does not react with chlorine. f) A substance decomposes on hearting.
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 8
Classify as : Physical or Chemical properties. a) Density b) Ability to burn c) Explosiveness d) Solubility e) Melting point f) Corrosiveness
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 9
A PHYSICAL CHANGE This is a change which causes no change in
composition. E.g. the melting of ice
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 10
A CHEMICAL CHANGE Is one which is accompanied by a change in
composition. It involves the disappearance of one or more
substances ( reactants) and the appearance of one or more new substance (product). These changes are referred to as CHEMICAL REACTIONS.
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 11
Classify as : Physical or chemical changes. a) Freezing water. b) Rusting of Iron. c) Evaporation of dry
ice. d) Explosion of gun
powder. e) Tearing of paper.
f) Digesting of food. g) Absorption of a
vitamin from the intestinal tract.
h) Detoxification of a drug in the liver.
i) Synthesis of protein in muscle tissue.
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 12
ENERGY Is the capacity to do work. It can not be destroyed. It can be converted from one form into another.
Gravitational potential energy to kinetic energy. Electrical to kinetic. Electrical to thermal (heat).
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 13
A PURE SUBSTANCE This substance has a definite, invariable composition
and cannot be separated into simpler substance by physical means.
HOW IS IT TO DETERMINED WHETHER A SUBSTANCE IS PURE OR NOT ?
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 14
A MIXTURE Is a combination of two or more substances in which
the substances retain their identities. i.e. there in no chemical reaction between their
components. The components may be separated by physical means
E.g. salt + water The components may be in any proportion
E.g. concentrated or diluted orange juice.
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 15
A HETEROGENEOUS MIXTURE This mixture contain two or more phases. e.g
Sausage and cheese pizza Concrete Sand and water Oil and vinegar (salad dressing) Blood Milk of magnesia
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 16
A HOMOGENEOUS MIXTURE This mixture contain only one phase e.g.
Sugar dissolve in water Air Metal alloys Gastric juice Spinal tap fluid
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 17
Are the following classification a pure or as mixture? a) Copper b) Air c) Milk d) Water e) Concrete
f) Wine g) Sulphur h) Sugar solution i) Blood j) Urine
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 18
Are each of the following mixture homogeneous or heterogeneous? a) Salt and pepper b) Alcohol and water c) Sulphur and iron d) Two different salts e) Milk of magnesia suspension f) 5% dextrose in water (used for injection)
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 19
A MOLECULE It made up of atoms which are chemically bonded
together. It can be broken down into smaller units only if
chemical changes are allowed to take place.
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 20
AN ATOM This represents the limits of chemical subdivision of a
molecule. E.g. pure substance can be divided into two classes.
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 21
ELEMENTS Are pure substance composed of homoatomic
molecules i.e atoms of one type. e.g
Oxygen (O2) Iron (Fe) Carbon (C)
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 22
COMPOUNDS Are pure substances composed of heteroatomic
molecules i.e two or more kinds of atoms. Carbon dioxide ( CO2) Suphuric acid ( H2SO4) Sodium chloride (NaCl)
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 23
Classify these classes as heterogeneous mixture, homogeneous mixture, pure substance, compound, element. a) In which of these classes must two or more substance
present? b) Which of these classes could not possibly contain
heteroatomic molecules? c) A variable composition is possible for which of these
classes?
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 24
Classify the following as: elements, compounds or no such classification
a) Analysis with some elaborate instruments indicates that substance A contains only aluminium atoms.
b) Substance B and substance C react to give a new substance D
c) Substance E decomposes on heating to give substance F and substance G.
d) Heating substance H to 800 degrees causes no change in it.
e) Analysis shows that substance I contains sulphur and oxygen.
f) Heating substance J to 620 degrees causes it to change from a solid to a liquid. PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 25
Indicate whether each of the following statements is TRUE or FALSE. If it false, change it to make it true. a) Some pure substance may be decomposed into simpler
substances by chemical change. b) The smallest characteristic unit of a pure substance is an
atom. c) Molecules of pure substances are always heteroatomic. d) Heterogeneous mixtures can be separated into
component substance by physical means. e) In order for matter to be heterogeneous at least two
substances must be present. f) Pure substance can be variable composite. g) The limit of physical subdivision is a molecule. h) A compound contain only one type of molecule.
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 26
PROPERTIES OF METALS Solid (one liquid – mercury) Shiny Malleable – can be pounded into sheets. Ductile – can be drawn into wires. High electrical conductivity. High thermal conductivity Oxides, if soluble, form alkaline solutions in water. Tend to form positive ions
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 27
PROPERTIES OF NON-METALS Generally gases, some solids, one liquid Not shiny Not malleable nor ductile Poor conductors of heat or electricity Oxides, if soluble, form acidic solutions in water Tend to form negative ions.
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 28
ATOMIC STRUCTURE AND PERIODIC TABLE.
PS Nkosi, Durban University of Technology, Department of Clothing and Textile Studies 29