Chapter 18: How Chemicals MixBIG IDEA: Most everything is a mixture

18.1 Most Materials are Mixtures

Mixture- a combination of 2 or more substances in which each substance retains its own properties.

-Each substance in a mixture maintains its chemical identity

The components of mixtures can be separated from one another by using differences in their physical properties.-Differences in: state of matter, density, boiling/melting points

Ex: filtration: separating a solid/liquid mixture via filter paperEx: distillation: separating a solid/liquid mixture via heating

18.2 Chemist’s Classification of MatterPure materials consist of a single element or compoundImpure materials are a mixture of 2+ elements or compounds

Classification of mixtures: Heterogeneous vs. Homogenous- Uneven composition throughout- Even composition throughout

Homogenous mixtures can be solutions or suspensions

Solution: All components are in the same phase

Suspension: Different components are in different phases

-The easiest way to tell the 2 apart is to spin in centrifuge

18.3 Making SolutionsSolutions aren’t always liquids (gemstones=solid, air=gas)

In solutions the component present in the largest amount is the solvent, all other components are solutes.

Ex: Salt water. Water= solvent b/c substance is dissolved in itSalt= Solute, it’s the component being dissolved

There is a limit to how much of a solute can be dissolved.

-In saturated solutions no more solute can be dissolved-Unsaturated solutions have not yet reached their dissolving limit

Identify solvent vs. solute

Which is solvent, which is solute?

Salt water

Air (A solution of 78% N2, 21%O2 and various other gases)

Bronze (95% Cu, 5% Sn)

Kool-Aid

18.4 Concentration and the Mole

Concentration=

- Something that is less concentrated is more watered down

A mole of any type of particles = 6.02 ∙1023

molecules

Avogadro's number

Another common unit of concentration used by chemists:

Molarity=

1 molar solution= 1M= 1 mole/L solution

- Higher molarity=higher saturation=

higher concentration.

18.5 Solubility

Solubility= ability of a solute to dissolve in a solvent.Can dissolve= solubleCan NOT dissolve= insoluble

-Solubility depends on the microscopic attractions between solute particles and solvent particles

Solubility increases w/:

Increased temperatures(More kinetic energy, particle movement increases)

Broken into smaller pieces or being stirred. (More surface area [amount of space something takes up] comes into contact w/ the solvent

18.6 Soaps and DetergentsSoap works b/c it has both nonpolar and polar properties

_Polar heads are attracted to nonpolar grime. The nonpolar tails are attracted to water, so this allows the soap + water to flow and get the grime off.

Detergents=stronger grease penetration

Purifying the Water we DrinkWe purify water by taking advantage of the differences in physical properties of water and the solutes/particles it contains

1.Take groundwater/ lake/river water and remove pathogens by mixing w/ chemicals.

2.The impurities clump together and settle @ bottom

3.Water is filtered

People also make drinking water by boiling the source water