Properties of Matter
Matter - anything that has mass and takes up space Chemistry - the study of the properties of matter and how matter changes
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.
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.
Walking Through Paper
Ivory Soap The Soap That Floats
Bromothymol Blue ph indicator CO 2 + H 2 O make carbonic acid
Carbon Snake exothermic reaction
Physical Change - a change in a substance that does not change its identity
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
Chemical Change - a change in which one or more substances combine or break apart to form new substances
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
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
malleability - ability of a substance to be flattened into thin sheets
ductility - ability of a substance to be pulled into a wire
elasticity - ability of an object to resume its normal shape after being stretched or compressed
tensile strength - resistance of a material to breaking under tension
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
buoyancy - ability to float
viscosity - a liquid s resistance to flowing honey has a higher viscosity than water
solubility - ability of a substance to dissolve in another substance sugar and salt are soluble in water; sand and pepper are not
conductivity - ability of a material to allow heat or electricity to flow through it
magnetism - a property that allows some materials to attract iron and other metals
flammability - ability of a substance to burn or ignite
reactivity - tendency of a substance to undergo a chemical reaction rust, tarnish, react with water, react with acid, etc.
Solid has a definite shape and a definite volume particles are packed tightly together in a fixed position; can vibrate slightly
crystalline solids have particles arranged in a regular, repeating pattern melt at a specific temperature examples: sugar, salt, snow, quartz
amorphous solids have particles which are not arranged in a regular pattern when heated, become softer and softer examples: wax, rubber, glass, plastic, butter
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)
surface tension forms within liquids as the molecules of the liquid are attracted to each other surface acts like it has a thin skin
viscosity - a liquid s resistance to flowing honey has a higher viscosity than water
Gas does not have a definite shape or a definite volume; expands to fill its container fluid compressed = higher pressure
adding energy will cause a gas to expand taking energy away will cause it to contract
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)
Freezing - changing from a liquid to a solid thermal energy decreases; particles slow down and begin to form the regular patterns of a solid
Sublimation - changing from a solid to a gas bypass the liquid stage examples: snow disappearing, dry ice
Vaporization - changing from a liquid to a gas on the surface = evaporation within a liquid = boiling
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)
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
Thermal expansion - the tendency of matter to change in volume in response to a change in temperature
Water contracts as it is cooled until it reaches 4 C, then expands while it freezes (4 C - 0 C).