Mixtures The form in which most matter exists
Definition of Mixture • A combination of 2 or more kinds of matter that CAN be separated by physical means because they are combined physically. • The “things” that make a mixture keep their physical properties. Therefore those physical properties can be used to separate the mixture. • Example?
Heterogeneous Different through out, like…….. Homogeneous The same through out, like….. Major Classifications of Mixtures
Homogeneous Solutions Heterogeneous Suspensions Colloids Types of Heterogeneous and Homogeneous Mixtures
Solutions (homogeneous) • The same through out • Particles do not settle so you don’t have to shake them • Do not scatter light • Cannot be separated by filtering • Ex: sugar water, Cough syrups that do not need to be shook
Solutions, cont’d Parts of a solution: • Solute (the thing that gets dissolved) Ex: salt • Solvent (the thing that does the dissolving) Ex: water
Solubility for Solutions • The amount of a solute that can be dissolved in a solvent at a given temperature.
HUH?????????????? • In other words…..if you had a cup of tea at 99 degrees celcius and another at 25 degrees celcius, which could you dissolve more sugar in?
At 99 degrees, you might be able to dissolve 30 grams At 25 degrees, you might be able to dissolve 10 grams Solubility, cont’d These are the solubilities of sugar in tea at those two given temperatures Get it??????????????
To Increase the Solubility of a solid + a liquid • Raise the temperature!
Will that work with a Gas and a Liquid? Like in making soda….
NO!!!!!!!! • As it is,gases are less dense than liquids …raising the temperature is just going to make them even LESS dense and want to float out of the liquid!
So how do they get gases to dissolve in liquid? Think…….what could you do to make a gas MORE dense????????
Dissolving a Gas in a liquid….Aka, making sodaTo Increase the solubility of a gas and a liquid • Increase the pressure! (makes the gas particles move closer together, becoming more dense) • Lower the temperature! (also makes the gas particles move closer together, becoming more dense) (Remember Boyles’ and Charles’ Laws???)
So….what affects Rate of Solution? For Solids+Liquids • Temp.up; faster • Temp. down; slower • Nature of solute/solvent • Stir/mix • Increase surface area
Saturated: A solution where all of the solute that can be dissolved at a given temp. has been dissolved Unsaturated: A solution that could dissolve more solute Super saturated: Has more solute dissolved than is normal at a given temp. Dilute: Amount of solute is small compared to the solvent Concentrated: amount of solute is high compared to the solvent Solution Concentrations
Suspensions (heterogeneous) • Different through out • Particles settle out, needs to be stirred/shaken • Particles are large enough to scatter light • Can be separated by filtering
Colloids (heterogeneous) Have Properties of Solutions and Suspensions • Scatters light (like a suspension) • Can not be separated by filtering (like a solution) • Different through out fog milk
Mixtures are physically combined, therefore can be physically separated The ingredients of a mixture keep their physical properties, therefore those properties can be used to separate the mixture Compounds are combined chemically, all the way down to their electrons The elements that make a compound change their physical properties. Therefore a compound must be chemically separated (chem. rxn) How are Mixtures and Compounds Different?