Chemistry Flashcards
Solid
Hold particles close together in rigid shape
Particle Theory
- All matter is made up of tiny particles that have empty spaces between them
- Different substances are made up of difference kinds of particles
- Particles are in constant random motion
- The particles of a substance move faster as its temperature increases
- Particles attract each other
Liquid
Particles move faster as it gets hotter, gaining more energy.
When there’s enough thermal energy, particles start sliding past each other because attraction between particles can no longer hold them together
Gas
If heating continues, particles gain so much energy they fly apart
Particles so far apart their forces of attraction have little effect on behaviour
Purpose of Alloys
Solder (tin&lead) used to join metal components together such as wires and pipes -quickly solidifies to firmly hold parts together
Alloys Associated Hazards
Lead poisoning causes irreversible damage to brain, kidneys, heart, reproductive organs especially in growing children
Many have been replaced with less hazardous materials
Physical Properties of Common Substances
Lustre Optical Clarity Brittleness Hardness Malleability Ductility Electrical Conductivity
Quantitative Physical Properties
Temperature, Height, Mass
Density
Mass / Volume
Density graphs
As density increases, line gets steeper
Physical vs. Chemical Properties
Physical - substance characteristics determined without changing composition of substance
Chemical - substance characteristics determined with changing composition of substance and one or more new substances are produced
Physical Change
Composition of substance remains exactly same, no new substances are made
Chemical Changes
Colour Odour Gas production (bubbles visible not caused by heating) Precipitate production (new solid seen, often powdery) Energy change (change in temperature/light)
Characteristic Physical Properties
Freezing Point: liquid to solid
Melting Point: solid to liquid
Boiling Point: liquid to gas
Element
Pure substance can’t be broken down into simpler chemical substance by any chemical/physical means
Compound
Pure substance composed of two or more different elements that are chemically joined