Matter and Related Terms Chapter 2
MATTER yes no MIXTURE PURE SUBSTANCE yes no yes no Homogeneous Mixture Can it be physically separated? MIXTURE PURE SUBSTANCE yes Is the composition uniform? no yes Can it be chemically decomposed? no Homogeneous Mixture (solution) Heterogeneous Mixture Compound Element Colloids Suspensions
Pure Substances Elements composed of identical atoms EX: copper wire, aluminum foil
Pure Substances Compounds composed of 2 or more elements in a fixed ratio properties differ from those of individual elements EX: table salt (NaCl)
Mixtures Variable combination of 2 or more pure substances. Heterogeneous Homogeneous
Mixtures Solution homogeneous very small particles no Tyndall effect particles don’t settle EX: rubbing alcohol
Mixtures Colloid heterogeneous medium-sized particles Tyndall effect particles don’t settle EX: milk
Mixtures Suspension heterogeneous large particles Tyndall effect particles settle EX: fresh-squeezed lemonade
Mixtures Examples: colloid mayonnaise suspension muddy water solution (homogeneous) Examples: mayonnaise muddy water saltwater Italian salad dressing
Physical and Chemical Changes How to tell the difference
Physical Change Substance may seem different, but the way the atoms link up is the same.
It’s a physical change if It changes shape or size It dissolves.
It changes phase (freezes, boils, evaporates, condenses) It’s a physical change if... It changes phase (freezes, boils, evaporates, condenses)
Chemical Change Changes the way the molecules link up Makes new substances
It’s a chemical change if…. It burns Temperature changes without heating/cooling
It’s a chemical change if... It bubbles (makes a gas)
It’s a chemical change if... It changes color It forms a precipitate
What kind of change is it if someone... Tears up paper? Physical change Mixes salt and water?
What kind of change is it if someone... Burns paper? Chemical change Evaporates salt water? Physical change
What kind of change is it if someone... Mixes vinegar and baking soda? Chemical change