Vocabulary
Matter that has a fixed composition, the same properties throughout every sample, and is composed of only one type of particle
pure substance
NaCl (table salt) or Gold (Au)
pure substance
How can you tell if a substance is pure by observation?
It has a uniform composition, consistent properties no matter the sample size, and cannot be separated physically.
Method using paper or strainer to separate solids from liquids
filtration
Claim for salt water (not dissolved). Classify (pure substance or mixture). It is a _______.
It is a homogeneous mixture.
A pure substance made of only one type of atom, cannot be broken down chemically.
element
Salad, trail mix, or sand and water
heterogeneous mixture
How can you tell a mixture is heterogeneous?
Parts are visible and the composition is not uniform; it can be separated physically.
Heating a liquid until it evaporates, leaving solids behind
evaporation
Evidence for salt water. I observed ___________.
I observed that it can be separated physically, and it is uniform in composition.
A pure substance made of two or more elements chemically combined in a fixed ratio.
compound
Oxygen (O₂) or gold (Au)
element
Why is a compound different from a mixture?
Compounds are chemically combined and cannot be separated physically; mixtures can.
Using a magnet to separate iron filings from sand
magnetism
Reasoning for salt water. It is a ______ because ___________.
It is a homogeneous mixture because it is uniform in composition and can be separated physically.
Matter that contains two or more substances physically combined that keep their own properties.
mixture
Salt water or gatorade
homogeneous mixture
How can evidence from separation methods help classify a sample?
Observing whether components can be physically separated shows if it’s a mixture or pure substance.
Evidence that filtration worked on sand and water
Sand stays on filter, water passes through
Claim for pure water. (classify as pure substance or mixture). It is a ________.
It is a pure substance (compound).
A mixture that looks uniform throughout.
homogeneous mixture
Water (H₂O) or carbon dioxide (CO₂)
compound
What evidence shows a solution has a solute and solvent? (salt water)
The mixture looks uniform, but the solute can be separated by physically.
Evidence that evaporation works on salt water.
Salt on pan.
reasoning for pure water. (It is a __________ because __________.)
It is a pure substance-compound because it cannot be separated physically; uniform composition shows it is a compound made of H and O in a fixed ratio.