The science of Matter
Deals with the structure and composition of matter
Deals with the changes that matter undergoes and the energy involved that accompany these change
Utilization:
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Inorganic Chemistry - study of all elements and their compounds except the element carbon.
Organic Chemistry - study of carbon compounds, specifically hydrocarbons and their derivatives.
Biochemistry - study of compounds present in living organisms and their interaction with one another.
Physical Chemistry - study of physical processes in chemical reactions.
Analytical Chemistry - study of what and how much substance is present in a particular sample of matter.
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Ancient Babylonians - Chemistry as an art of brewing wine and extracting metals from ores.
Ancient Egyptians - Chemistry as an art of embalming, cosmetics and making paper from papyrus.
Ancient Greeks and Romans
Middle Ages - Chemistry as an art of alchemy ( philosopher’s stone)
16TH Century - Chemistry as analytical science.
Modern Chemistry:
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L3: The Nature of Matter
Democritus - matter is made up of small/tiny, uncut & indivisible particles called atomos/atoms.
Matter has mass and occupies space.
Matter can be classified according to their structure and composition.
Atoms are single neutral particles; Molecules are particles made of two or more atoms bonded together
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Inter-convertibility depends on pressure and temperature.
Matter exists in three states:
SOLID:
LIQUID:
GAS:
PHASE CHANGES:
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Explains the forces between molecules and the energy that they possess.
3 basic assumptions:
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The amount of matter and total mass remains the same.
All Physical and Chemical Changes involve some transfer of energy.
Law of Constant Composition (Law of Conservation of Mass) - All samples of a given compound have the same proportions of their constituent elements.
Law of Conservation of Energy - Energy is not created or destroyed, only changed.
Law of definite proportion – A given compound always contains exactly the same proportion of elements by mass.
Law of multiple proportions – When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers.
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Properties are used to identify and separate the substance
Matter can be classified as a mixture or a pure substance.
Matter undergoes physical and chemical changes:
A physical change involves a change in one or more physical properties but no change in composition.
A chemical change transforms a substance into one or more new substances.
Matter has both physical and chemical properties:
Physical properties are the characteristics of a substance that do not involve changing to another substance./ Properties that retain the identity of matter.
Chemical properties describe a substance’s ability to change to a different substance./ tend to change the identity of matter
EG:
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a blend of two or more kinds of matter, each of which retains its own identity and properties.
Homogeneous - Uniform in composition/ Exist in One phase (Saltwater, air, milk, alloys)
Heterogeneous - Not Uniform in appearance or throughout/ can be separated (pizza, concrete, salad)
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Composed of one kind of matter
Homogeneous in appearance/ always has the same composition
Pure substances are of two types:
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contain only one type of atom – elemental copper contains only copper atoms and elemental gold contains only gold atoms.
Periodic Table of Elements (118 elements)
Classified as:
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are substances that contain two or more different types of atoms./ chemically combined
Classifications (Chemical Bound):
Classifications (Acid/Base Properties):
Classifications (Presence of Carbon Element):
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Filtration - to filter a solid from a liquid/used for colloids & suspensions
Decantation - used when the mixture consists of substances of different densities. /used for suspensions only
Centrifugation - used when the substances have very similar densities, or when one of the substances consists of very fine particles suspended in a liquid.
Electrolysis – electric current to separate water into hydrogen gas and oxygen gas
Chromatography - this technique separates substances (dyes and pigments) on the basis of differences in solubility in a solvent.
Distillation - to remove dissolved substances from a liquid or to separate a mixture of liquids that have different boiling points.
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