Pure Substances and Mixtures: Unit Review

Any three: all matter is made of tiny particles; each pure substance has its own kind of particle; there are spaces between particles; particles are always moving; particles move faster when heated; particles attract each other.

Hot water particles move faster, so they bump the colouring particles around faster (faster diffusion).

The cold slows the air particles inside, so they hit the balloon's walls less hard and less often, and it shrinks.

Distilled water: pure substance. Granola: mixture. Helium: pure substance.

Two or more different kinds of particles mixed together, with a key.

It contains dissolved minerals as well as water, so it has more than one kind of particle.

Iron: element. CO₂: compound. O₂: element (one kind of atom).

2 carbon, 6 hydrogen, 1 oxygen (9 atoms in all).

A compound has atoms chemically joined in a fixed ratio with new properties; a mixture's parts are just mixed, in any amounts, and keep their properties.

Sodium.

Tea: homogeneous (solution). Trail mix: heterogeneous (mechanical mixture). Muddy water: heterogeneous (suspension).

An alloy, such as brass (copper + zinc), bronze or steel.

A suspension is cloudy and its pieces settle when left still; a solution is transparent and nothing settles.

Solute: salt. Solvent: water.

It decreases: less gas stays dissolved.

Water particles don't attract sand particles strongly enough to pull them apart, so the sand stays together: it's insoluble.

Use warmer water, stir, and use smaller pieces (more surface area).

No, only how fast it dissolves.

62 s. (62 + 58 + 66) ÷ 3 = 186 ÷ 3 = 62.

Independent: particle size. Dependent: time to dissolve.

60 g/L. 200 mL = 0.2 L, and 12 ÷ 0.2 = 60.

20 g in 50 mL = 40 g/100 mL, which is more than 36, so it is saturated, with about 2 g left undissolved (the most that can dissolve in 50 mL is 18 g).

Dilute means only a little solute. Saturated means it holds the most solute it can at that temperature.

It dissolves more substances than any other common liquid.

The hydrogen ends.

Salt dissolves in meltwater, and runoff carries the dissolved salt into streams and lakes.

Add water (salt dissolves), filter (sand stays behind), then evaporate the water to get the salt.

Distillation.

The dissolved substances in a mixture, such as the dyes in ink.

Winnowing: moving air carries away the light hulls.

A criterion is what the design must do; a constraint is a limit (time, materials, cost).

It catches big pieces first so the fine layers don't clog.

It can still contain germs and dissolved substances, which filters can't remove.

Fractional distillation.

Environmental (any): tailings, water and energy use, land damage. Social (any): jobs, worker safety risks, effects on nearby and Indigenous communities.

Cameras and AI recognize items on a moving belt, and air jets push them into the right bin.

Examples: copper (wires), gold (connectors), lithium (battery), silicon (chips).

They can start fires if crushed, and recycling recovers metals and keeps toxic substances out of landfills.

Local (any): mining jobs and environmental costs in Ontario, Ring of Fire decisions on First Nations' territories, e-waste in local landfills. Global (any): unsafe cobalt mines, conflict minerals, e-waste shipped overseas.