Pure Substances & Mixtures
What is a pure substance?
One type of particle
What is a solution?
Evenly dissolved mixture
How would you separate sand and water?
Filtration
What is matter?
Has mass and takes up space
What is one example of a mixture?
e.g. salt water, air
What is a mixture?
Two or more substances physically combined
Which type of mixture settles over time?
Suspension
How would you separate iron and sand?
Magnetic separation
Which state of matter has tightly packed particles?
Solid
What is one example of a solid, a liquid, and a gas?
Any valid examples
Is salt water a pure substance or a mixture, and why?
Mixture (contains more than one substance)
Why does a suspension settle but a colloid does not?
Suspension has large particles that settle; colloid has smaller particles that do not
Why does filtration separate sand from water?
Sand is insoluble and cannot pass through filter paper
How do particles move in a liquid?
Close together, move past each other
Why is air considered a mixture?
Air contains multiple gases
How can you tell the difference between a homogeneous and heterogeneous mixture?
Homogeneous = evenly mixed; heterogeneous = visible parts
Why does a colloid appear cloudy but does not settle?
Particles are small enough to stay mixed but still scatter light
Why is evaporation used to separate sugar from water?
Sugar is dissolved, so water must evaporate to leave it behind
Why are gases easy to compress?
Particles are far apart
Why does oil float on water?
Oil is less dense and immiscible with water
Why can mixtures be separated physically but pure substances cannot?
Mixtures are not chemically joined; pure substances are one type of particle
How can you identify whether a mixture is a solution, colloid, or suspension using particle size and settling?
Solution = very small particles/no settling; colloid = medium/no settling; suspension = large/settles
What is the correct order of steps to separate iron, sand, salt, and water, and why does this order work?
Magnet → filtration → evaporation (based on properties like magnetism, solubility, particle size)
Why does perfume spread across a room using particle theory?
Gas particles move freely and spread out
Why does muddy water become clearer over time?
Larger particles settle due to gravity