Chemistry: The Study of Matter

What is Chemistry? The study of the matter, its composition, properties, and the changes it undergoes. The study of the matter, its composition, properties, and the changes it undergoes. A natural science. A natural science. a language with its own vocabulary. a language with its own vocabulary. a way of thinking. a way of thinking.

Review of matter: Matter: anything that takes up space (volume) and has a mass. Matter: anything that takes up space (volume) and has a mass. Physical Properties: like different densities, melting points, boiling points, freezing points, color or smells Physical Properties: like different densities, melting points, boiling points, freezing points, color or smells

Chemical Properties: A good example of chemical properties is the way elements combine with each other in reactions Chemical Properties: A good example of chemical properties is the way elements combine with each other in reactions

Review of states of matter Solid Liquid Gas Definite Volume? YES NO Definite Shape? YES NO Temperature increase Small Expansion Large Expansion Compressible? NO YES

Solid Liquid Gas Melt Evaporate Condense Freeze

Kinds of Change: physical change: no new substance is formed, properties such as size, shape, colour or state may change (eg. Boiling water) The reverse is possible chemical change: new substances (with new properties) are formed from 2 or more different elements. (eg. Rusting of iron) The reverse is not possible

Properties Words that describe matter (adjectives) Words that describe matter (adjectives) Physical Properties- a property that can be observed and measured without changing the composition of the substance. Physical Properties- a property that can be observed and measured without changing the composition of the substance. Chemical Properties- a property that can only be observed by changing the composition of the substance. Chemical Properties- a property that can only be observed by changing the composition of the substance.

Glossary: Pure substance: contains one type of particle. Ex: Elements and compounds: Pure substance: contains one type of particle. Ex: Elements and compounds: Mixture: contains two or more types of particles intermingling, no chemical bonding. Types are homogeneous and heterogeneous. Mixture: contains two or more types of particles intermingling, no chemical bonding. Types are homogeneous and heterogeneous.

Composed of two or more different atoms Composed of two or more different atoms Can be broken down by chemical methods and each part will have different properties Can be broken down by chemical methods and each part will have different properties Examples: Examples: water (H 2 O), 2 atoms of hydrogen, I atom of oxygen) salt (NaCl), 1 atom of sodium, 1 atom of chlorine

An element is a substance made up of only one kind of atom An element is a substance made up of only one kind of atom The periodic table arranges elements according to their properties The periodic table arranges elements according to their properties

Compound or Mixture CompoundMixture One kind of matter- Molecule or atom More than one kind of matter- different molecules or atoms Made during a chemical change Made through a physical change Definite and uniform composition Variable in composition

Which is it? Element Compound Mixture

Heterogeneous 2 or more parts can be seen Different kinds of particles stay together. Mechanical mixing Ex: sand and salt, blood, milk

Homogeneous Appear to be one substance Particles are intermingled May be solutions (something dissolved) Ex: air, salt water

Solutions Homogeneous mixture with molecules mixed uniformly Homogeneous mixture with molecules mixed uniformly Solutions occur between any state of matter. Solutions occur between any state of matter. Solid in liquid- Kool-aid Liquid in liquid- antifreeze Gas in a liquid – carbonated beverages Gas in gas- air Solid in solid - brass Liquid in gas- water vapor

Solutions Like all mixtures, the components keep their own properties. Like all mixtures, the components keep their own properties. Components can be separated by physical means Components can be separated by physical means

Chemical symbols There are 112 elements There are 112 elements Each has a 1 or two letter symbol Each has a 1 or two letter symbol First letter always capitalized second never First letter always capitalized second never Don’t need to memorize Don’t need to memorize Some from Latin or other languages Some from Latin or other languages

Chemical Reactions When one or more substances are changed into new substances. When one or more substances are changed into new substances. Reactants- stuff you start with Reactants- stuff you start with Products- What you make Products- What you make NEW PROPERTIES NEW PROPERTIES Not easily reversed Not easily reversed

Indications of a chemical reaction Energy absorbed or released Energy absorbed or released Color change Color change Gas produced Gas produced Precipitate- solid that separates from solution Precipitate- solid that separates from solution Not easily reversed Not easily reversed ALWAYS THERE IS A NEW SUBSTANCE! ALWAYS THERE IS A NEW SUBSTANCE!

Conservation of Mass Mass can not be created or destroyed in ordinary (not nuclear) changes. Mass can not be created or destroyed in ordinary (not nuclear) changes. All the mass can be accounted for. All the mass can be accounted for.

What about nuclear? E = mc 2 E = mc 2 energy = mass x (speed of light) 2 energy = mass x (speed of light) 2 speed of light = 3 x 10 8 speed of light = 3 x 10 8 A little mass can make a lot of energy A little mass can make a lot of energy Law of Conservation of Mass - Energy the total of the mass and energy remains the same in any change Law of Conservation of Mass - Energy the total of the mass and energy remains the same in any change

Energy The ability to do work. The ability to do work. Work - cause a change or move an object. Work - cause a change or move an object. Many types- all can be changed into the other. Many types- all can be changed into the other.

Types of energy Potential- stored energy Potential- stored energy Kinetic Energy- energy something has because its moving Kinetic Energy- energy something has because its moving Heat- the energy that moves because of a temperature difference. Heat- the energy that moves because of a temperature difference. Chemical energy- energy released or absorbed in a chemical change. Chemical energy- energy released or absorbed in a chemical change. Electrical energy - energy of moving charges Electrical energy - energy of moving charges

Types of Energy Radiant Energy- energy that can travel through empty space (light, UV, infrared, radio) Radiant Energy- energy that can travel through empty space (light, UV, infrared, radio) All types of energy can be converted into others. All types of energy can be converted into others. If you trace the source far enough back, you will end up at nuclear energy. If you trace the source far enough back, you will end up at nuclear energy.

Conservation of Energy Energy can be neither created or destroyed in ordinary changes (not nuclear), it can only change form. Energy can be neither created or destroyed in ordinary changes (not nuclear), it can only change form. Its not just a good idea, its the law. Its not just a good idea, its the law.

Assigned reading: Page 6-8 and Page 6-8 and Be able to define or explain the following terms/concepts Be able to define or explain the following terms/concepts Types of knowledge Types of knowledge Pure/applied science Pure/applied science Scientific method Scientific method Rules of experimentation Rules of experimentation Laws, theories and models Laws, theories and models