Solutions

Mixtures ___________: substances in mixture are not spread uniformly throughout mixture. __________: components uniformly mixed in solution The _____the particles the _______the mix.

Solutions: Homogeneous mixture of two or more substances, the composition of which may vary within limits. Consists of two parts: _______: (solid, liquid, gas) dissolved substance or substance present in the smaller amount. _______: (solid, liquid, gas) substance that the solute is dissolved in –dissolving medium or substance present in the larger amount.

Solutes and solvents Usually substances are two phases. Solute changes phase when placed in solvent. Examples: Aqueous: solvent is________ For example:__________ NaCl in water or ________ ______is solute and ______is solvent Tincture: solvent is ________(C2H5OH) tincture of iodine _______is solute and ______ is solvent

The quantity solute dissolved per unit of time. Rate of Dissolving The quantity solute dissolved per unit of time. How fast a solute dissolves Factors that affect the rate of dissolving: (think of a sugar cube in coffee) _______________

Solubility Quantity (mass) of solute which can be dissolved in a given volume of solvent at equilibrium, under specified conditions of temperature and pressure. Table ____tells you if something is soluble in water Table ____ tells you how much at a particular temperature. What factors affect the solubility of a substance?

Factors that Affect Solubility Nature of solute and solvent: “Like dissolves like” ______ and ______ solutes are soluble in _______solvents. (ex______) ________solutes are soluble in _____ solvents. Note: Alcohols are soluble in both polar and nonpolar solvents. Polar and nonpolar solutes are soluble in alcohol. But ionic solutes are insoluble in alcohols. Why? ______________________

Factors that Affect Solubility Temperature: For Ionic solids: as T____ solubility ____ example:_____________ For gases: as T _____ solubility ____ example: _________________

Factors that Affect Solubility Pressure: For solids/liquids: as P changes, solubility______________ For gases: as P____ solubility _______ (____________: escape of gas from solution)

How many types of solutions are there? Give an example of each type? There are ______different types of solutions. Solid in solid:_________________ Solid in liquid: _______________ Solid in gas: ________________ Liquid in Solid: _______________ Liquid in liquid: ______________ Liquid in gas: _________________ Gas in solid:___________________ Gas in liquid: __________________ Gas in gas: ____________________

There are three common solutions. Type 1: Gases in Liquids: In a closed system an equilibrium exists between the gas dissolved in the liquid and the undissolved gas above the liquid. The equilibrium is affected by ________ and___________. An increase in temperature _______the solubility. An increase in pressure _______the solubility. (Henry’s law: the mass of a gas which dissolves in a liquid at a given temperature is proportional to the partial pressure of the gas over the solution)

Type 2: Liquids in liquids There are other liquid solvents besides water. Some liquids mix together well while others do not. ________: Liquids that are soluble in one another. Mix well together. Ex: _____________ ________: Liquids that are insoluble in each other. Do not mix well together. Ex: _________________

Type 3: Solids in liquids A solution __________exists when the opposing processes of dissolving the solute in the solvent and of crystallizing the solute from the solvent occur at equal rates. At this point no further solute can be dissolved and the solution is known as ______________. General rule: the solubility of a solid ________as the temperature ________(Table G)

Looking at solubility Solubility curves show the relationship of grams of solute that may be dissolved in a solvent at various temperatures. The solubility curves on Table G in your reference table show the number of grams of a substance that can be dissolved in_______ ____ at temperatures between 0oC and 100oC. Each line represents the maximum amount of a substance that can be dissolved at a given temperature.

Table G: Solubility Curves All of the lines that show an increase in solubility as temperature increases represent ________being dissolved in water. Three lines show decreasing solubility with increasing temperature. These three lines represent_________and they are:________. Remember the solubility of all gases ______with increasing temperature.

Concentration The concentration of a solution may be expressed in a variety of ways Concentrated and dilute: because the terms are vague they are used for comparison only. __________: contains a relatively large amount of solute. __________: contains a relatively small amount of solute For example: _____________________

Unsaturated, Saturated and Supersaturated When reading the solubility curves on table G you will need to recognize three positions with respect to the line of maximum solubility. When a solution holds less solute than the maximum it can hold it is said to be___________. In this case the amount dissolved will be _______the line of solubilty. When a solution contains the maximum amount of solute that will dissolve at a specific temperature it is_________. In this case the amount dissolved will be _________the line of solubility. Solution____________. When a solution contains more than the maximum amount of solute that will dissolve at a specific temperature it is____________. In this case the amount dissolved will be ________the line of solubility. Made from a saturated solution at a _______temperature and then ________it. These solutions are________. One more crystal will cause immediate ___________.

Table G

Recognizing Unsaturated, Saturated, and Supersaturated One method of recognizing the type of solution is if it contains some undissolved solute, it must be a saturated solution. The addition of more solute crystals can also determine the conditions. If it dissolves, the original solution was____________. If it simply falls to the bottom of the container then it is________________. If it causes additional crystals to form, the original solution was_______________.

Concentration of Solution The concentration of a solution is a measurement of the amount of solute dissolved in solution. There are several ways of expressing the specific concentration of solute in a solution. Percent by Mass Percent by Volume Parts per million Molarity Molality

Percent by Mass & Percent by Volume Percent by mass is simply the mass of the solute divided by the total mass of the solution, expressed as a percentage (x100). Use a % sign as the unit. Percent by volume is simply the volume of the solute divided by the total volume of the solution, expressed as a percentage (x100). Use a % sign as the unit. Percent by mass = X Percent by volume = X

Parts Per Million X Parts Per Million = Parts per million (ppm) is similar to percent by mass because it compares masses. It represents the ratio between the mass of a solute and the total mass of a solution. Instead of multiply by 100 you multiply by 1,000,000. ppm is often used to measure concentrations of solutes that are present in very small amounts. For example if you wanted to measure the concentration of chloride ions in tap water. The units for parts per million are ppm X Parts Per Million =

Molarity Molarity (M) = Molarity measures the concentration of a solution in terms of moles of solute in a given volume of solution. The Molarity (M) of a solution is the number of _____of solute in _______ of solution. When calculating the Molarity of a solution you may need to make conversions before you solve for and answer. For example if you are given the mass of the solute you will need to convert to moles using the mole calculation equation on Table T. You may also need to convert the volume of solution given if it is not in liters. Molarity (M) =

Molarity by Dilution Most acids are purchased from laboratory supply houses in concentrated form. If you want to make a different concentration of acid use the formula below: ________________ Where: M1=initial concentration V1= initial volume M2= final concentration V2= final volume

Molality Molality is the number of ______of solute per ____ of solvent. ___________

Helpful Hint about Concentration Problems. Remember that a solution is made up of the______ and ______ combined. So if you are performing a concentration problem you may need to add the masses or volumes of your “solute” and “solvent” to solve for the mass or volume of the “solution”, which is what you need for all concentration equations. If you are given the mass or volume of the “solution” then you do not need to worry about adding the solute and the solvent. Solution =

Colligative Properties Properties that depend on the number of particles rather than the nature of particles are called____________. For example:________, _______, osmotic pressure and vapor pressure.

Non-electrolytes Non-electrolytes are molecular substances that ______break up into ions (i.e.____________) _______conduct an electric current (Why? ______________) Non-electrolytes have a dissociation factor (d.f.) of_____. C12H22O11  C12H22O11 (aq) 1 mole 1 mole

Electrolytes Electrolytes are ________that ___________when put in solution. For example:________________________________ Conduct electricity due to___________ NaCl  The dissociation factor is equal to_______. The more moles of ions produced, the greater the effect on colligative properties.

Freezing Point Depression Freezing point is_______ when a non-volatile substance (non-electrolyte) is added to a solvent. When one mole of a nonelectrolyte is added to 1 kg of water the freezing point is lowered by 1.86 degrees celcius. For electrolytes the _______particles the ______ the freezing point. Example:_________________________ Change in f.p. =____________________

Compare the following: 1 mole of magnesium chloride or 1 mole of sugar in 500g of water Which will have the lowest freezing point? Which will have the highest freezing point? Freezing point will always be lower than 0°C.

Boiling Point ELevation Boiling point is _________when a non-volatile substance (non-electrolyte) is added to a solvent. When one mole of a nonelectrolyte is added to 1 kg of water the boiling point goes up by .52 degrees celcius. For electrolytes the _______particles the _______ the boiling point. Example:___________________________ Change in b.p. =____________________

Compare the following: 1 mole of calcium chloride or 1 mole of ethyl alcohol in 500 g of water. Which will have the highest boiling point? Which will have the lowest boiling point? Boiling point will always be higher than 100°C.