Solutions~ And some questions about chapter 11 (Zumdahl)

What are solutions? Solutions are a mixture. They can be… – Gas/ gas ( air!!!) or you gas/ liquid ( soda) – Solid/ solid (marble, granite) – Liquid/liquid – Alloys! Metal solutions, brass, steel

Properties Solute – stuff that goes in ( lesser in amount) Solvent -what it goes into ( greater in amount) Soluble- can be dissolved Insoluble – can’t dissolve Generally- like dissolves like ( organics together, or two inorganic)

Words to describe mixtures Miscible and immiscible- to mix or not to mix Solution – 2 or more substances, evenly distributed, very small solute particles, stays mixed. Colloid – Substances are still visible, solute particles won’t come out of solution, but not entirely dissolved – ( milk, clouds, fog, smog, mayo) Suspension- – Large particles, will fall out of solution or can be filtered out. Salad dressing,,

Concentrations! Molarity! Concentrations can be in moles per liter or moles per kilogram. ( moles is solute, liter or kilogram is the solvent) Moles per liter is M molarity Moles per kg is m molality Mole fraction moles of component per total moles of solution Mass percent, grams solute/ grams total x100

Mass percent, mole fraction By mass, or by mole, it is part over whole to figure out how much a part is of the whole

Saturated, super and un A saturated solution is one where all the solute that can be put into solution is. ( for that temp) Supersaturated- when a solution has more solute than it should hold for the temp. If you need to “fix” that, you can “seed” your solution Unsaturated- solution has less than “full” amount of solute

Some things that effect solubility Nature of solvent/solute- like dissolves like, liquids and gases dissolve faster than solids. Temperature. For solids and liquids, higher temps mean faster dissolving. For gases, warmer means less dissolves. Pressure- more pressure means more gas goes into solution.

Temp. and pressure cont. As you look at the solubility charts you see that not all substances follow the solubility rule. Some things get less soluble with higher temps. See pg 496 Pressure- the pressure of a gas in a liquid is equal to the pressure of the gas over the liquid- if you want gas to stay in solution- pressurize it.

Henry’s Law C=kP so that the c is the concentration of the gas, k is a constant you look up that relates to the gas, and P is the pressure over the gas. Works best with dilute not reactive gases If soda at 25 Celsius has 5.0 atm pressure of CO 2 before opening and the atmospheric pressure of carbon dioxide is 4 x10 -4 ( after opening) what is the concentration of CO 2 before and after? K for carbon dioxide is 3.1 x10 -2 mol/liter

Factors effecting the rate of dissolving Surface area- the more surface there is for interaction the faster solvation will occur Agitating- stirring, shaking etc speed molecules Temperature- heat it up, speed it up