Properties of Matter

Transcription

1 Properties of Matter

2 Matter - anything that has mass and takes up space Chemistry - the study of the properties of matter and how matter changes

3 Physical Property - a characteristic of a substance which can be observed without changing it into another substance examples: hardness, texture, color, boiling point, melting point, freezing point, etc.

4 Chemical Property - a characteristic of a substance that describes its ability to change into different substances examples: flammability, ability to rust/tarnish, ability to react with acids, etc.

5 Walking Through Paper

6 Ivory Soap The Soap That Floats

7 Bromothymol Blue ph indicator CO 2 + H 2 O make carbonic acid

8 Carbon Snake exothermic reaction

9 Physical Change - a change in a substance that does not change its identity

10 change in size, shape, or phase (solid, liquid, gas) does not change what the substance is is often reversible examples: dissolving, crushing, cutting, melting, freezing, evaporating

11 Chemical Change - a change in which one or more substances combine or break apart to form new substances

12 changes the chemical makeup of the substance often accompanied by release of a gas, color change, odor, release of heat usually not reversible examples: burning, rusting, baking, digestion, photosynthesis

13 Conservation of Mass - matter cannot be created or destroyed through chemical or physical changes In a chemical reaction, all atoms present at the start of a reaction are present at the end ex. Photosynthesis: 6CO 2 + 6H 2 O C 6 H 12 O 6 + 6O 2

14 malleability - ability of a substance to be flattened into thin sheets

15 ductility - ability of a substance to be pulled into a wire

16 elasticity - ability of an object to resume its normal shape after being stretched or compressed

17 tensile strength - resistance of a material to breaking under tension

18 density - amount of matter in a given space (mass divided by volume) mass - amount of matter in a object volume - amount of space that a substance takes up

19 buoyancy - ability to float

20 viscosity - a liquid s resistance to flowing honey has a higher viscosity than water

21 solubility - ability of a substance to dissolve in another substance sugar and salt are soluble in water; sand and pepper are not

22 conductivity - ability of a material to allow heat or electricity to flow through it

23 magnetism - a property that allows some materials to attract iron and other metals

24 flammability - ability of a substance to burn or ignite

25 reactivity - tendency of a substance to undergo a chemical reaction rust, tarnish, react with water, react with acid, etc.

26 Solid has a definite shape and a definite volume particles are packed tightly together in a fixed position; can vibrate slightly

27 crystalline solids have particles arranged in a regular, repeating pattern melt at a specific temperature examples: sugar, salt, snow, quartz

28 amorphous solids have particles which are not arranged in a regular pattern when heated, become softer and softer examples: wax, rubber, glass, plastic, butter

29 Liquid has a definite volume, but does not have a definite shape particles are packed tightly together, but are free to move around each other (fluid)

30 surface tension forms within liquids as the molecules of the liquid are attracted to each other surface acts like it has a thin skin

31 viscosity - a liquid s resistance to flowing honey has a higher viscosity than water

32 Gas does not have a definite shape or a definite volume; expands to fill its container fluid compressed = higher pressure

33 adding energy will cause a gas to expand taking energy away will cause it to contract

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35 Phase Changes/Changes of State Melting - changing from a solid to a liquid thermal energy increases; particles break free from their fixed positions melting point is the same temperature as freezing point (water = 0 C or 32 F)

36 Freezing - changing from a liquid to a solid thermal energy decreases; particles slow down and begin to form the regular patterns of a solid

37 Sublimation - changing from a solid to a gas bypass the liquid stage examples: snow disappearing, dry ice

38 Vaporization - changing from a liquid to a gas on the surface = evaporation within a liquid = boiling

39 the lower the atmospheric pressure is, the lower the boiling point will be Water boils at 100 C in San Diego (sea level), but at 95 C in Denver (1,600 m elevation)

40 Condensation - changing from a gas to a liquid Particles lose energy, slow down, and condense into a liquid examples: cold drink on hot day, mirror after shower, dew on leaves

41 Thermal expansion - the tendency of matter to change in volume in response to a change in temperature

42 Water contracts as it is cooled until it reaches 4 C, then expands while it freezes (4 C - 0 C).