Chemistry: Matter Part 1: The Classification of Matter The study of matter and its changes Matter: Anything that has mass and volume What is the Structure of Matter? are made of many Substances called either Compounds are made of or Elements of different Atoms are made of many substances. most matter you commonly encounter is a mixture. different substances can be separated from a mixture by simple, physical processes. Examples: Salt Water Soda Blood Rocks Soil Trees Air (Con( Con t) Example: Salt Water Distillation A Simple Physical Separation of a Mixture to obtain pure substances Can be separated into two substances: water and salt 1
Filtration (Con( Con t) Example: Soda A Simple Physical Separation of a Mixture to obtain pure substances Can be separated into several substances: water and sugars and dyes and presevatives etc etc. (Con( Con t) Example: Soil (Dirt) or Rocks Con t This is obviously a mixture; you can see more than one substance present: This is also a mixture, even though it looks like it is a pure substance. v Can be separated into many, many substances: muscovite and biotite and feldspar and iron etc etc. Two Types of Mixture: Homogeneous Mixture An even mixture; particles are blended evenly throughout the mixture. (a.k.a. solutions ) Heterogeneous Mixture: An uneven mixture; particles are unevenly distributed. are made of many substances. most matter you commonly encounter is a mixture. different substances can be separated from a mixture by simple, physical processes. mixtures are made of many Examples: Salt Water Soda Blood Rocks Soil Trees 2
Substances (Pure) Substance also called PURE SUBSTANCES cannot be further separated or broken down by simple physical processes Examples: Water Salt Gold Copper Butane DEFINITION: An element or a compound. Can always be represented by a single chemical formula. Substances You might recognize that of these substances are elements whereas others are compounds. Examples: Water Salt Gold Copper Butane Compounds DEFINITION: A substance containing more than one element. Examples: Water (H 2 O) contains Hydrogen Oxygen Salt (NaCl( NaCl) contains Sodium Chlorine Butane (C 6 H 12 O 6 ) contains Carbon Hydrogen Oxygen Electrolysis vs. Compounds Water is not a mixture, so it cannot be separated into simpler substances by physical means but it can be separated into simpler substances by CHEMICAL means. Water is a compound because it is a substance containing more than one element. can be separated by PHYSICAL means into Compounds and/or Elements Example: Distillation Compounds can only be separated by CHEMICAL means into Elements Example: Electrolysis
vs. Compounds are made of compounds and/or elements that are MIXED together. Compounds are made of atoms of different elements that are BONDED together. Compounds, (Con( Con t) Molecular compounds are made of atoms that bond together to form molecules. Ionic compounds are made of atoms that bond together to form networks. In this example, methanol molecules and water molecules are mixed together; not bonded together. This is a pure substance; oxygen atoms and hydrogen atoms are bonded together to form a compound, hydrogen peroxide (H 2 O 2 ) Elements Each element has a name and symbol: DEFINITION: An element is a substance that cannot be broken down into simpler substances. Examples; Iron (Fe) Carbon (C) Chlorine (Cl( Cl) Mercury (Hg) There are about 117 elements. A A type of atom Not all elements are equally common: A Matter Flowchart yes MATTER Can it be physically separated? no MIXTURE PURE SUBSTANCE yes Is the composition uniform? no yes Can it be chemically decomposed? no Homogeneous Mixture (solution) Heterogeneous Mixture Compound Element 4
Atoms All elements are made of atoms Atoms are the most basic building block of matter DEFINTION: ( that has the properties of the element) Here is a picture of an atom:? The structure of an atom is The smallest particle of an not easy to determine; element they are too small to be observed directly. Too Easy? Here s s a much more advanced and comprehensive look at classifying matter. Matter Part 2: Molecules and Chemical Formulae Review: Atom: The basic unit of matter Element: A type of atom Molecule: A group of atoms held together by sharing electrons (covalent bonds) Examples: Compound: A substance containing more than one element. Atom, Element, Molecule, Compound: 5
Four different molecules: Which are compounds? Some molecules are more complex: Some fat molecules: A protein molecule: cholester What are each of these? There can be different forms of a single element Oxygen has 2 allotropes: Atom, Element, Molecule, or Compound O 2 Diatomic Oxygen Molecule O Ozone Molecule Forms of Carbon Practice with Vocabulary: Diamond Graphite All are pure carbon; each has a different molecular or crystalline form. Fullerenes Carbon Nanotubes 6
Molecules can be represented many ways: Chemical Formula: Structural Formula: Ball and Stick Model: CH 4 H 2 O H O H All substances can be represented by a Chemical Formula: H 2 O subscript Space Filling Model: Chemical Formulas show how many atoms of each element are in one molecule: Chemical Formula O 2 H 2 O C H 8 O C 6 H 12 O 4 Cl # of elements 1 2 4 # of atoms total 2 12 2 # of Carbon atoms 0 0 6 How many atoms of each element are present in one molecule of: (NH 4 ) 2 SO N. H S. O 2 8 1 Review: Classification of Matter Pure Substance or Mixture? 7
Pure Substance: = An element or a compound (Any substance that can be described by a single chemical formula) Homogeneous Mixture An even mixture; particles are blended evenly throughout the mixture. (= solutions ) Mixture: A substance that contains more than one pure substance Heterogeneous Mixture: An uneven mixture; particles are unevenly distributed. Homogeneous Mixture An even mixture; particles are blended evenly throughout the mixture. (= solutions ) Heterogeneous Mixture: An uneven mixture; particles are unevenly distributed. All pure substances can be represented by a Single Chemical Formula: H 2 O If it s really a pure substance, you should only need to write ONE chemical formula to describe it s composition. 8