CHEMISTRY – Chapter 1 & 2 Matter, Measurements, and Calculations
Chapter 1 – Section 1 Objectives: • Define chemistry • List examples of branches of chemistry • Compare and contrast basic research, applied research, and technological development
What objects in this room are related to chemistry? • Plastics • Fabrics • Clothes • Cooking oil • Motor oil • Make-up • Radio • Batteries • Computers
Chemistry in our daily lives. • Antibiotics • Food • Transportation • Sports • Farming • Military • Industry
Chemistry • Study of the composition and properties of matter and the changes that matter undergoes • What something is made of • What is the internal arrangement
Chemical • Any substance that has a definite composition
6 Main Branches of Chemistry • Organic – substances containing C • Inorganic – substances other than organic • Biochemistry – living things • Physical chemistry – changes of matter • Analytical chemistry – id components of materials • Theoretical chemistry – use math and computers to understand chemical behavior
All branches involve some type of research. Basic research – to increase knowledge • how and why Applied research – to solve problems Technological development – production and use of products - lags behind discoveries - application of knowledge
Review and Assignment 1. Define chemistry 2. List examples of branches of chemistry 3. Compare and contrast basic research, applied research, and technological development Assignment: WS 1-1
Quiz • Name two branches of chemistry. • List two ways that chemistry affects our daily lives. • Definition of chemistry.
Chapter 1 – Section 2 Objectives: • Distinguish between a mixture and a pure substance. • Define what matter is.
Matter • anything that has mass and occupies space • includes almost everything • exceptions are light, heat, and sound • properties are used to measure matter ex. mass Mass – measure of quantity of matter - not affected by temp, location, or any other factor
Demo. • Mass vs. matter • What caused the change in mass? • Is air matter?
Matter (cont.) Classified into 2 groups: 1. pure substances 2. mixtures Pure substance – matter that has the same properties throughout ex. element or compound
Pure Substances Element – substance that cannot be broken down by ordinary chemical change - only 1 type of atom - symbols abbreviated w/1 or 2 letters - can be an allotrope allotrope – one of a number of different molecular forms of an element in the same state Compound – substance made up of 2 or more elements chemically combined - can be broken down by chemical change - more than 1 type of atom
Compounds • Elements that make up a compound are combined in definite proportion by mass ex. 100 g water has 11.2 g H and 88.8 g of O 2. Chemical and physical properties of compound differ from those of its parts ex. water is liquid, H and O are gases 3. Compounds can be formed from simpler substances by chem change and can be broken down into simpler substances
example 100 of water has 11.2 g H and 88.8 g O How many g of H is in a 120g sample of water? 120 g water | 11.2 g H = 13.4 g H | 100 g water
Mixtures - contain 2 or more substances that have different properties - vary in composition and properties from sample to sample ex. rock, wood, salt water • Not chemically combined • Can be separated by simple physical means • ie. filtration, evaporation, distillation
Formation of Mixtures A mixture can be formed 3 ways: • Element mixed w/1 or more other elements ex. carbon w/sulfur 2. Compound mixed w/ 1 or more other compounds ex. salt w/sugar 3. 1 or more elements mixed w/1 or more compounds ex. sulfur w/sugar
Characteristics of Mixtures - retain properties of each of its parts ex. iron and sulfur - iron remains magnetic - composition can vary widely - can be homogeneous or heterogeneous
Types of mixtures Homogeneous – uniform composition throughout - called solutions ex. alloys, pop, air, coffee Heterogeneous – not uniform throughout ex. concrete, soil, dry soup, spaghetti and meat balls
Review and Assignment 1. Distinguish between a mixture and a pure substance. 2. Define what matter is. Assignment: WS
Chapter 1 – Section 2 Objectives: 1. Distinguish between the physical properties and chemical properties of matter. 2. Classify changes of matter as physical or chemical. 3. Explain the gas, liquid, and solid states in terms of particles.
Properties of Matter • allow us to distinguish btwn substances • characteristics of a substance • what can be observed • way that a substance behaves ex. color, taste, odor, gas, liquid, solid
Properties (cont.) - can be extensive or intensive Extensive – d/o amount of matter ex. volume, weight, mass, and E Intensive – does not d/o amount of matter ex. melting point, boiling point, density, and conductivity
Demonstration • Properties - water and glycerin How do they compare? - look, feel, weight, flow - water and salt water How do they compare? - conductivity
Physical Properties • Can be observed or measured w/out changing the substance • Can describe the substance • Odor, taste, hardness, density, melting point, and boiling point • Metals – ductile (pulled into wire), malleable (hammered into sheets), luster (shine), good conductors
Chemical Properties • A transformation of a substance into a different one • rusting, flammability, tarnishing, new substance formed
Physical Change • No new substance is formed • CHANGE IN PHASE, pounding, grinding, cutting • Changes of phase • When a substance changes phase there is no change in composition • Physically different, chemically the same • Solid, liquid, or gas are the three states of matter
States of Matter • Solid – definite volume and shape • Particles are in fixed positions • Held w/strong attractive forces • Liquid – definite volume and no definite shape • Takes shape of container • Particles can move past each other
States of Matter (cont.) • Gas – neither definite volume nor definite shape • Particles move easily and are very far apart • Plasma – high temperature state in which atoms lose their electrons
Chemical Change • One or more substance is changed to something new • Rusting, burning, gas formed, digestion, heat or light added, explosion, color change, odor change, water formed
Review and Assignment 1.Distinguish between the physical properties and chemical properties of matter. 2. Classify changes of matter as physical or chemical. 3. Explain the gas, liquid, and solid states in terms of particles. Assignment: p. 18 and WS
CHEMISTRY – Chapter 1 – Section 3 Objectives: Perform density calculations. Describe conservation of mass.
Properties of Matter • E is always involved in both physical and chemical changes • Physical are not at noticable • Chemical are more noticable • Heat and light are given off
Density • is a physical property • is always the same for a solid substance • in gases and some liquids a change in temperature will change the density • increase in temperature will decrease density • D = m/V
Density problem Use the 5 steps in problem solving to solve the following problem. Lead has a mass of 22.7 g and its volume is 2.00 cm3. What is its density? m = 22.7 g V = 2.00 cm3 D = m/V = 22.7 g/2.00 cm3 = 11.4 g/ cm3
Conservation of Mass • In reactions matter cannot be created or destroyed by a chemical change - mass stays the same, it may just change form
Density Lab Results Group 1 – Group 2 – Group 3 – Group 4 – Group 5 -
Review and Assignment 1. Perform density calculations. 2. Describe conservation of mass. Assignment: WS and Density lab
Chapter 2 - Sec.1 Objectives: • Describe the purpose of the scientific method. • Distinguish between qualitative and quantitative observations. • Describe the steps to making a graph. • Distinguish between inversely and directly proportional relationships.
Scientific Method - a logical approach to solving problems 1. Make observations • observe your surroundings 2. State the problem - stated as a question 3. Collect data 4. Form hypothesis - testable statement 5. Test hypothesis 6. Conclusion 7. Modify hypothesis and retest
Observing • Involves making measurements and collecting data • Data can be qualitative or quantitative Qualitative – non-numerical information - descriptive (the sky is blue) Quantitative – numerical information - the mass is 25.7 grams
Conclusion • Can be explained by using models Model – explanation of how phenomena occur or how things are related - visual - verbal - mathmatical
Theory • models may become part a theory Theory – broad generalization that explains facts or phenomena - must be able to predict results ex. kinetic-molecular theory collision theory
Controlled Experiments • Use manipulated variable (independent) • Use responding variable (dependent) • One variable manipulated at a time • Measurements are called data
Making a Graph • Shows results of an experiment in a meaningful pattern • Dependent variable is on the vertical axis 1. Always include a title 2. Determine variables 3. Set up scale 4. Plot points 5. Draw best-fit line