1. Modern Chemistry Chapter 1 Matter and Change

2. 1-1 Chemistry is a Physical Science Chemistry is the study of the composition, structure, and properties of matter and the changes is undergoes. Branches of Chemistry Organic Chemistry – study of most carbon compounds Inorganic Chemistry – study of inorganic compounds (no carbon) Physical Chemistry – study of properties and changes of matter and their relation to energy Analytical Chemistry – identification of the components and composition of materials Biochemistry – study of substances and processes occurring in living things Theoretical Chemistry – use of mathematics and computers to understand the principles behind observed chemical behavior and to design new compounds

3. 1-1 Chemistry is a Physical Science Some Basic Definitions Chemical - substance with a definite composition (ex: sucrose, water) Basic Research – increases knowledge Applied research – solves a specific problem Technological Development – production and use of products that improve the quality of life

4. 1-2 Matter and Its Properties Matter – anything that has mass and takes up space Volume – amount of space an object takes up Mass – the amount of matter present (how much “stuff” there is) Atom – smallest unit of an element that maintains properties of that element Element – a pure substance made of only one kind of atom (on Periodic Table) Compound – a substance made from 2 or more elements chemically bonded Molecule – smallest unit of an element or compound that retains all of the properties of that element or compound Properties – characteristics of substances used to classify matter Extensive Property – depends on the amount of matter (ex: volume, mass, temperature) Intensive Property – independent of the amount of matter (melting point, density, boiling point) Physical Property – observed or measured without changing the identity of the substance (ex: size, color, melting point, shape) Chemical Property – relates to a substance’s ability to undergo changes that transform it into a different substance (ex: charcoal will burn in air, iron will rust)

5. 1-2 Matter and Its Properties Physical Change – does NOT change the identity of the substance (ex: grinding, cutting, melting, boiling, freezing) Changing from one state to another (melting, freezing, vaporizing, condensing, etc.) does NOT change what the substance is made of and, therefore, is a PHYSICAL CHANGE. States (Phases) of Matter Solid:definite shape and volume closely packed particles particles vibrate about fixed points Liquid:definite volume, indefinite shape particles move closely around each other (they flow) particles move more rapidly Gas:no definite volume or shape (take the shape of container) particles space far apart particles move very rapidly weaker attractive forces Plasma:exists only at high temperatures atoms have lost their electrons examples include stars and fluorescent bulbs

6. 1-2 Matter and Its Properties Chemical Change – (chemical reaction) – a change in which one or more substances are converted into different substances (ex: rusting, burning) reactants – substances that react in a chemical change (what you start with) products – substances formed in a chemical change (what you end with) example:C + O 2 ---  CO 2 carbon plus oxygen yields carbon dioxide Law of Conservation of Mass: matter is not created or destroyed in chemical changes Energy – always involved in physical and/or chemical changes (it is absorbed or released) Law of Conservation of Energy: energy can be absorbed or released in a chemical or physical change, but it is NOT created or destroyed

7. 1-2 Matter and Its Properties Classification of Matter Matter can be broken into two parts: mixtures and pure substances Mixture:a blend of two or more kinds of matter, each retaining its own identity and properties (a mixture will use the word AND) - physically combined in no definite proportion - come in two types: Homogeneous mixture (solution) – uniform in composition (ex: air, sugar water, stainless steel) Heterogeneous mixture – non-uniform (ex: clay and water, granite, wood, blood) Pure Substance: has a fixed composition - every sample has the exact same properties -every sample has the exact same composition - come in two types: compounds – can be decomposed by a chemical change (ex: water, salt [sodium chloride], sucrose) has 2 or more elements elements – building block of matter; cannot be decomposed (ex: gold, iron, chlorine – they are on the periodic table)

8. 1-3 Elements The elements are organized into the Periodic Table Periodic Table – chart organizing the elements Groups/Families – vertical columns of elements with similar properties Periods/Series – horizontal rows with elements having properties that change in a regular way Types of Elements Metals – on the left side of the periodic table - good conductors of heat and electricity - are malleable (can be hammered into sheets) - usually solids at room temperature - have luster (shiny) - are ductile (can be drawn into thin wires) - have tensile strength (resist breaking when stretched)

9. 1-3 Elements Types of Elements continued Metalloids – elements on the dividing line between metals and nonmetals - properties of both metals and nonmetals - semiconductors Nonmetals – on the right side of the periodic table - poor conductors of heat and electricity - brittle solids - many are gases at room temperature Noble Gases – Group 18 - usually unreactive