Chapter 7: Solutions

Heterogeneous Mixtures (2 types) - amount of each substance in a heterogeneous mixture varies - no fixed composition 1) ______- a mixture in which particles of a material are more or less evenly distributed throughout a liquid or gas - particles settle out over time - Ex.- orange juice - particles can be filtered out of solution - ______- when two liquids do not mix - Ex.- oil and water - some salad dressings (oil and vinegar) - ______- process of pouring a lighter liquid off of a heavier liquid 2) ______- a mixture consisting of tiny particles that are intermediate in size between those in solutions and those in suspensions and that are suspended in a liquid, solid, or gas - particles smaller than those in suspensions - pass through ______- do not settle out - scatter light (______Effect) - Ex.- paint - solid particles of pigment in water - Ex.- gelatin, egg white, blood plasma, whipped cream (gas in liquid), fog (water in air), smoke (solids in air), marshmallow (gas in solid) 2

- ______- a colloid in which liquids that normally do not mix are spread throughout each other - Ex.- mayonnaise - made of oil and water - egg yolk ______oil and keeps them from forming a separate layer - ______- protein that keeps lipid droplets dispersed in water Homogeneous Mixture - are uniform throughout - Ex.- salt water - Na and Cl ions surrounded by H2O molecules - not chemically combined - salt water can be separated by evaporation - ______- a homogeneous mixture of two or more substances uniformly dispersed throughout a single layer - ______- part of a solution that gets dissolved - ______- part of a solution that does the dissolving - Ex.- salt water - solute = salt - solvent = water - ______- when two liquids mix that form a single layer - difficult to separate (no layering) - ______- can be used to separate liquids with different boiling points - heat liquids, one boils first - leaves other behind 3

- petroleum contains several carbon based fuels - distillation is used to separate them - ______can come from other states of matter - solutes and solvents can be in any ______- Ex.- vinegar…two liquids - air…several gases - sort drinks…CO2 in liquid - mothballs…naphthalene vapor forms solution with air - amalgam…liquid mercury dissolved in ______silver - brass…solid dissolved in solid - must be melted to mix - ____- a solid or liquid mixture of two or more metals or non-metals - water is called ______- dissolves many different substances - made of an oxygen ______bonded to two hydrogens - oxygen strongly attracts the ______- electrons bunch around oxygen - oxygen becomes “_____“ - hydrogens become “______” - slightly charged - ______compound- a molecule that has an uneven distribution of electrons δ+ or δ- - water molecules attract both positive and negative ions of an ionic compound

- Ex.- water dissolving NaCl - “+” hydrogen ion attracts “-“ ______ion - more hydrogens show up increasing ______- eventually pull is greater than force between Na and Cl - Cl breaks free and is surrounded by ______molecules - same thing happens between “-“ oxygen and “+” Na ions

***for a solvent to dissolve a substance, the force of attraction between the solvent and the solute must be greater than the forces of attraction between the particles in the solute***

- ______bonding- the intermolecular force occurring when a hydrogen atom that is bonded to highly electronegative atom of one molecule is attracted to two ______electrons of another molecule - “+” hydrogen of one molecule attracts “-“ oxygen of another 5

- allows dissolving of some ______compounds - Ex.- sugar (C6H12O6) - bonds between H and O are ____ - water’s polarity form hydrogen bonds with the sugar molecules at those points - force is ______than forces in sugar molecule - ______- like dissolves like - solvents will dissolve substances with similar ______structure - Ex.- water is polar - dissolves substances that are ionic or polar - charged - Ex.- non-polar substances dissolve other non-polar materials 6

- ______compounds- a compound whose electrons are ______distributed among its atoms - water does not attract non-polar molecules enough to ______it from the compound

Speed up dissolving (3 ways) 1) ______- break into smaller pieces - more solute-solvent ______- Ex.- 1 cm cube = 6cm2 - cut into 1000 cubes .06 cm2/cube X 1000 cubes = 60 cm2 ______the surface area

2) ______- more contacts between solute and solvent

3) ______- solvent particles move faster - more contacts

***Does not apply to ______dissolved in liquids*** 7

- as it gets warmer or as pressure decreases, less gas is ______- water molecules move apart and ______gas - divers and nitrogen in blood - dissolves at higher pressure - if diver comes to surface to quickly - N2 comes out of solution and causes “the _____” - solutes can affect ______of a solution - Ex.- adding ethylene glycol to water in a car - anti-freeze 0 - H2O freezes at -30 C 0 - H2O boils at 109 C - Ex.- salt for ice - freezing point is about -150 C - ______- when one substance is able to be dissolved in another - ______- when one substance is unable to be dissolved in another - ______- the maximum amount of a solute that will dissolve in a given quantity of solvent at a given temperature and pressure 0 (usually 100 g H2O at 20 C) - Ex.- in 100 g of water at room temperature 36 g of salt can dissolve - some substances are completely soluble - no limit to the amount that can be added - Ex.- methanol, ethanol, acetic acid - different substances have different ______- solubility depends on strength of forces between molecules vs. force between molecule and solvent 8

- ______- the quantity of solute dissolved in a given volume of solution - ______- solution with lots of solute - ____- solution with small amount of solute - ______solution- a solution that contains less solute than a saturated solution does and that is able to dissolve additional solute - able to dissolve more solute - ______solution- a solution that cannot dissolve any more solute under the given conditions - in equilibrium - appears as if nothing is occurring, but for every particle dissolving, one comes out of solution - if you continue to add solute - sits on bottom of container 9

- ______solution- a solution that holds more dissolved solute than is required to reach equilibrium at a given temperature - very ______- heat solution…holds more solute - ______solution - may not re-crystallize - any disturbance will cause extras solve to come out of solution until it reaches ______(Solubility Graph Overhead)

- ______- an expression of the concentration of a solution in moles of dissolved solute per liter of solution

molarity = moles of ______or M = mol liters of solution L - Ex.- calculate the molarity of sodium carbonate, Na2CO3, in a solution of 38.6 g of solute in .5 L of solution

1) ______- given: mass of Na2CO3 = 38.6 g volume of solution = .5 L - unknown: molarity

2) ______moles Na2CO3 = mass Na2CO3 . molar mass Na2CO3 molarity = moles Na2CO3 volume of solution 10

3) find number of _____ Na2CO3 and calculate molarity molar mass Na2CO3 = 106 g moles Na2CO3 = 38.6 g = .364 mol Na2CO3 106 g molarity of solution = .364 mol Na2CO3 = .728 M .5 L solution

Practice Problems Determine the molarity of each of the following solutions. 1) 2 mol of calcium chloride, CaCl2, dissolved in 1L of solution. 2) .75 mol of copper (II) sulfate, CuSO4, dissolved in1L of solution. 3) 2.25 mol of sulfuric acid, H2SO4, dissolved in 725 mL of solution. 4) 525 g of lead (II) nitrate, Pb(NO3)2, dissolved in 1250 mL of solution.

ANSWERS 1)

- other measures of concentration - ______percent - grams of solute per 100g of solution - Ex.- 5% solution of NaCl - dissolve 5g of NaCl in 95g of H2O - ppm or ppb - parts per ______or parts per ______