Matter and Change. Chapter 1

Transcription

1 Matter and Change Chapter 1

2 Anything that bites or scratches is biology. Anything that snaps or bubbles is chemistry. Anything that doesn t work is physics.

3 Chemistry is the study of composition, structure and properties of matter and the changes it undergoes.

4 Branches of Chemistry Organic Chemistry- carbon containing compounds Inorganic Chemistry- noncarbon containing compds.

5 Physical Chemistry- matter s relationship to energy Analytical Chemistry- Identification of matter Theoretical Chemistry- the use of mathematics and computers to understand chemical behavior and design and predict new compds.

6 Definite Composition A chemical is a substance with definite composition. Definite composition means it has the same proportion of atoms that make it up. Ex. H 2 O Water always has 2 atoms of hydrogen and 1 oxygen atom

7 Research Basic Research-for increasing knowledge Ex. What are electrons made of? What is Saturn s atmosphere made up of? Applied Research-for solving a problem Ex. A cure for AIDS, Developing a substitute of Freon that does not harm the ozone in the upper atmosphere

8 Technology Technological Development Producing products that improve our quality of life Ex. Catalytic converters that reduce air pollution from cars. Section review p. 7

9 Matter Matter- anything that has mass and volume Mass- amount of matter Weight- depends on gravitational pull Volume- amount of space

10 Building Blocks of Matter Atom- smallest unit of an element that keeps the properties of that element. Element- Pure substance that made up of only one kind of atoms. Compound- substance made up of two or more elements chemically bonded.

11 Properties Chemists use properties to distinguish between substances and to separate them. By comparing several properties of a subst, an unknown subst can be identified.

12 Properties Extensive property- depend on the amount matter such as mass Intensive property- does not depend on the amount of matter, such as odor.

13 Types of Properties Extensive properties depend on the amount of matter. Examples: size, mass, weight, volume Intensive properties depend on the type of matter. Examples: absorbency, flammability, ability to rust, hardness, melting point, density

14 Extensive or Intensive? Property Extensive Intensive Waterproof Mass = 600 g Good insulator Elastic Circumference = 75 cm

15 Physical Properties Physical Properties- can be observed or measured without changing the identity of the subst Ex. Observing and measuring the boiling pt of water Physical Change- a change that doesn t involve changing the identity of the subst Ex. Liquid water changing to water vapor when boiled

16 Physical States of Matter Solid- definite shape and volume. Particles tightly packed in fixed positions and can only vibrate.

17 Liquid- definite volume, indefinite shape. Particles can flow past each other (fluid)

18 Gas- indefinite shape, indefinite volume, fluid. Particles move more rapidly with lots of space in between. Particles take up volume and shape of container

19 Plasma- high temperature matter where atoms lose their electrons. Ex. The sun

20 Chemical Properties Chemical Properties- substance's ability to undergo changes to form new substances Ex: ability of iron to react with oxygen to form rust

21 Chemical Change Chemical Change or Chemical Reactionchange where one subst is changed to a new subst Energy is always involved in chemical and physical changes

22 Chemical Reaction/change Chemical Reaction: Reactant Product Ex. Carbon plus oxygen yields (forms or produces) carbon dioxide Rxn: Note: products of a chemical change or reaction have properties very different from the reactants. Consider what carbon and oxygen gas is like and what carbon dioxide is like.

23 Chemical Changes Compounds can be broken down into simpler substances through chemical changes, but elements cannot. Sucrose Carbon + water vapor

24 Chemical Changes, cont. A chemical change produces matter with a different composition from the original matter.

25 Chemical Changes, cont. A chemical change produces matter with a different composition from the original matter. Sodium chloride

26 Classification of Matter Mixture- blend of two or more kinds of matter, each with its own identity and properties 2 types of mixtures: Homogeneous mixture or solution- uniform throughout Ex. Kool aid drink, 14k gold Heterogeneous drink- not uniform throughout Ex. Sample of dirt

27 Pure Substance Pure substance- a substance with the same properties throughout and same composition throughout Ex. Pure water has same lack of taste, color, boiling pt, density It is always made up of 11.2% hydrogen and 88.8% oxygen by mass

28 Pure Substances An element is the simplest form of matter that has a unique set of properties. A compound contains two or more elements that are chemically combined in a set ratio. 1. Silver sulfide is a(n) compound. carbon, sodium, silver, etc. 2. An example of an element is. C 3. 6 H 12 O 11, CO 2, NH 4, etc. is an example of a compound.

29 How Is Matter Classified? Substances Can be separated physically Mixtures Can be separated chemically

30 Classifying Matter Stainless steel Mercury sulfide Granite Mercury

31 Since water is a compound it can be broken down into its elements. Electrolysis is used to break down water to hydrogen and oxygen Section Review p. 18

32 Flow Chart Matter Pure Substances Mixtures Elements Compounds Homogeneous Mixtures Heterogeneous mixtures

33 Chemistry and You Would you want to eat this for breakfast?

34 Practice: Element or Compound? When a certain blue-green solid is heated, a colorless gas and a black solid form. All three materials are substances. Is it possible to classify these substances as elements or compounds? 1. Identify the relevant concepts. heat Blue-green solid + black solid 2. Apply concepts to this situation.

35 Symbols and Formulas Chemists use chemical symbols to represent elements and use chemical formulas to represent compounds. Au O Zn

36 Symbols and Latin Names Antimony Cu Gold Ag Fe Lead Sn

37 Chemical Formulas Symbol for hydrogen H 2 O Symbol for oxygen Symbol for carbon Subscript for hydrogen C 12 H 22 O 11 Symbol for oxygen Subscript for oxygen Subscript for carbon Symbol for hydrogen Subscript for hydrogen

38 Periodic Table Groups or Families - vertical columns of elements in the periodic table. Numbered 1-18 OR with A/B system Periods - horizontal rows of elements in the periodic table. Numbered 1-7 Ex. Ge is located in group and period

39 The Periodic Table Elements are separated into groups based on a set of repeating properties.

40 Metals and Nonmetals The periodic table is divided into two main sections: Metals and Nonmetals

41 Metals elements that are: Ex. Cu, Ni, Al good conductors of electricity and heat solids at room temp with luster ductile (drawn into wires) malleable (hammered into sheets) tensile strength (resist breaking when pulled)

42 Nonmetals elements that are : Poor conductors of heat and electricity Many gases Brittle Ex. C, O, S

43 Metalloids Elements with characteristics of both metals and nonmetals Ex. Si conducts electricity at high temp, not low temp; used as a semiconductor for computers

44 Noble Gases Noble Gases- elements in Grp 18 (8A) that are generally nonreactive Ex. He, Ne, Ar Section Review p. 24

45 Separating Mixtures 1. Filtration-for heterogeneous mixtures made of solids and liquids Technique that uses a barrier to separate Mixture is poured through a piece of filter paper. The liquid passes through leaving the solids trapped on the filter paper.

46 Filtration

47 2. Distillation for homogeneous mixtures Separation technique that is based on the boiling point of the substance See diagram:

48 Distillation

49 3. Crystallization Separation technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance. When the substance contains as much dissolved substance as it can possible hold, the addition of a tiny amount more causes the dissolved substance to come out of solution and collect crystals

50 4. Chromatography Separation technique that separates the components of a mixture by solubility Separated on the basis of the tendency of each to travel across the surface of another material