* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 1 Introduction to Chemistry
Photopolymer wikipedia , lookup
California Green Chemistry Initiative wikipedia , lookup
Physical organic chemistry wikipedia , lookup
Abundance of the chemical elements wikipedia , lookup
Stoichiometry wikipedia , lookup
Water pollution wikipedia , lookup
Water splitting wikipedia , lookup
Electrolysis of water wikipedia , lookup
Chemical element wikipedia , lookup
Analytical chemistry wikipedia , lookup
Freshwater environmental quality parameters wikipedia , lookup
Condensed matter physics wikipedia , lookup
Chemistry: A Volatile History wikipedia , lookup
Drug discovery wikipedia , lookup
Chemical thermodynamics wikipedia , lookup
Safety data sheet wikipedia , lookup
IUPAC nomenclature of inorganic chemistry 2005 wikipedia , lookup
History of chemistry wikipedia , lookup
Gas chromatography–mass spectrometry wikipedia , lookup
Registration, Evaluation, Authorisation and Restriction of Chemicals wikipedia , lookup
Chapter 1 Introduction to Chemistry What you’ll learn… You will describe the relationships between chemistry and matter You will recognize how scientific methods can be used to solve problems You will distinguish between scientific research and technology Chemistry and Matter Chemistry is the study of matter and the changes that it undergoes Matter is anything that has a mass and takes up space Mass is a measurement that reflects the amount of matter Is air matter? Weight is a measurement not only of the amount of matter but also the effect of the Earth’s gravitational pull on that matter Why would scientists use “mass” instead of “weight”? Macroscopic vs. Microscopic Macroscopic matter does not need a microscope to see it whereas microscopic matter needs a microscope Submicroscopic= atoms •FYI: 1 million million atoms could fit onto the period at the end of a sentence Scientific Methods Observations Qualitative Data- information that describes •Examples: color, odor, shape Quantitative Data- numerical information •Examples: how tall, how fast, how much Experiments Independent variable- variable that you plan to change Dependent variable- variable that changes in response to a change in the independent variable Chapter 3 Matter- Properties and Changes What about Chapter 2??? (We’ll come back to that…) Pure Substance Substance- matter that has a uniform and unchanging composition Examples: Table Salt, water, sugar Physical Properties of Matter A physical property can be observed or measured without changing the sample’s composition Examples: Density, Color, Odor, Taste, Hardness, Melting Point, Boiling Point Extensive vs. Intensive Properties Extensive Properties are dependent upon the amount of substance present Example: Mass Intensive Properties are independent of the amount of substance present Example: Density, Color Chemical Properties of Matter Chemical property -the ability of a substance to combine with or change into one or more other substances Example: The ability of iron to form rust when combined with oxygen States of Matter Solid Liquid Definite shape Definite volume Flows Constant volume Takes the shape of its container Gas Flows to conform to the shape of its container Fills entire volume of container Vapor- refers to the gaseous state of a substance that is a solid or a liquid at room temperature Physical Change Physical changes alter a substance without changing its composition Example: cutting a sheet of paper •Indicating words: bend, grind, crush, split, melting, freezing, condense Chemical Changes AKA Chemical Reaction A process that involves one or more substances changing into new substances Conservation of Mass The law of conservation of mass states that matter is neither created nor destroyed (it is conserved) WOOD + OXYGEN ASH + WATER VAPOR + CARBON DIOXIDE Chemical or Physical Change? wind eroding rocks _________________________ dead leaves decaying __________________________ rain puddle drying up __________________________ mixing flour and baking powder__________________________ gasoline evaporating __________________________ hydrogen peroxide decomposing__________________________ bread baking in an oven __________________________ instant tea dissolving in water __________________________ milk souring __________________________ gasoline burning __________________________ ANSWERS wind eroding rocks – PHYSICAL CHANGE dead leaves decaying – CHEMICAL CHANGE rain puddle drying up – PHYSICAL CHANGE mixing flour and baking powder- PHYSICAL CHANGE gasoline evaporating – PHYSICAL CHANGE hydrogen peroxide decomposing- CHEMICAL CHANGE bread baking in an oven – CHEMICAL CHANGE instant tea dissolving in water – PHYSICAL CHANGE milk souring – CHEMICAL CHANGE gasoline burning- CHEMICAL CHANGE Mixtures A mixture is a combination of two or more substances in which each pure substance retains its individual chemical properties Heterogeneous Mixture- one that does not blend smoothly throughout and which the individual substances remain distinct • Examples: Sand and Water, Oil and Water, Cement Homogeneous Mixture (Solutions)- has constant composition throughout; it always has a single phase • Examples: salt water, vinegar, alloys Separating Mixtures 1. 2. 3. 4. Filtration- technique that uses a porous barrier to separate a solid from a liquid Distillation- technique that is based on differences in the boiling points of substances Crystallization- technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance Chromatography- separates the components of a mixture on the basis of the tendency of each to travel or be drawn across the surface of another material Elements and Compounds Element- a pure substance that cannot be separated into simpler substances Located on the periodic table in rows and periods • Periods= Horizontal Rows • Groups= Vertical Columns Compound- a combination of two or more different elements that are combined chemically Law of Definite Proportions Elements comprising compounds combine in definite proportions Regardless of the amount, a compound is always composed of the same elements in the same proportion by mass Percent by Mass- the ratio of the mass of each element to the total mass of the compound as a percentage mass of element percent by mass (%) x100 mass of compound Practice Problem A 78.0g sample of an unknown compound contains 12.4 g of hydrogen. What is the percent by mass of hydrogen in the compound? 12.4g Percent by mass x100 78.0g 15.9% Hydrogen Material Limestone (CaCO3) Soil Bronze Aluminum Sugar + water Concrete Sterling Silver Caffeine Pure Substance or Mixture Element, Compound, Homogeneous, Heterogeneous ANSWERS Material Pure Substance or Mixture Element, Compound, Homogeneous, Heterogeneous PURE SUBSTANCE COMPOUND Soil MIXTURE HETEROGENOUS Bronze MIXTURE HOMOGENOUS PURE SUBSTANCE ELEMENT Sugar + water MIXTURE HOMOGENOUS Concrete MIXTURE HETEROGENOUS Sterling Silver MIXTURE HOMOGEN PURE SUBSTANCE COMPOUND Limestone (CaCO3) Aluminum Caffeine Homework Page 9 Page 13 #15-17 Page 76 #1-5 Page 69 #12 Page 60 #6-8,10 #21-23 Page 77 #25-30 SKIP #28