teachemrosinski.files.wordpress.com … · Web viewSolutions. Unit 10 Page 1. Learning Target: I can. describe the unique role of water in chemical and biological systems. Criteria

SolutionsUnit 10 Page 1

Learning Target:I can describe the unique role of water in chemical and biological systems.

Criteria for Success:I can describe the structure of a water molecule.

I can discuss the physical properties of water.I can explain the role of water in the solution process.

Water and the Solution Process

A. A _________________________________________ bond is a covalent bond in which the bonded atoms have an

______________________ attraction for the shared electrons.

1. Generally speaking, __________________________________ bonds occur between atoms with electronegativity

differences of _______________________.

B. A water molecule consists of two atoms of ______________________ and one atom of _____________________ united by

________________________________________ bonds.

1. The _________________ nature of the water molecule allows for ________________________ bonding between water

molecules which contributes to some of water’s unique properties.

a. _____________________ _______________________is the inward force or pull that tends to minimize the

__________________ ___________________ of a liquid. Water has a relatively ________________ surface tension.

b. Water has a relatively __________________ boiling point due to the extensive _______________________

bonding that occurs between water molecules.

c. Hydrogen bonding holds water molecules in a __________________________ arrangement in the solid

form. This allows the solid form of water to occupy a greater volume and therefore smaller

_________________________.

C. An __________________________ solution is ______________________ that contains dissolved substances.

1. In a solution, the dissolving medium is the ________________________ and the dissolved particles in a solution

are the ___________________.

2. Substances that dissolve most readily in water include _________________ compounds and ___________________

_______________________ compounds.

a. The _____________________ nature of the water molecule allows the negative end of the water

molecule to attract positive charges in a solute and the positive end of the water molecule to attract

negative charges in a solute.

b. The process by which the positive and negative ions of an ionic solid become surround by solvent

molecules is called _________________________.

Mini Lab: Surface TensionProcedure1. Thoroughly clean and dry the Petri dish.2. Fill the dish almost full with water. Dry your hands.3. Being careful not to break the surface, gently place the paper clip on the water. Observe what happens.

Analysis and Conclusions1. What happened to the paper clip in Step 3? Why?

2. If a paper clip becomes wet, does it float? Explain your answer.


Learning Target:I can describe the unique role of water in chemical and biological systems.

Criteria for Success:I can describe the terms dissociation and ionization.

I can write equations for the dissolution of soluble ionic compounds in water.

Water and the Solution ProcessA. An __________________________ solution is water that contains __________________________ substances.

B. The solution process depends on the __________________________ of attraction between the __________________________,

the thing getting dissolved, and the __________________________, the thing doing the dissolving (in many cases the

solvent is water).

1. There are attractive forces between the solute particles holding them together.

2. There are also attractive forces between the solvent molecules.

3. When we mix the solute with the solvent, there are attractive forces between the solute particles and the

solvent molecules.

4. If the attractions between solute and solvent are strong enough, the solute will dissolve.

Dissolution of Soluble Ionic Compounds

A. When an ________________ compound made of ________________ dissolves in water, the _______________

_________________________ from one another. This is called __________________________.

1. The number of ______________ produced in solution depends upon the ratio in the original formula.

NaCl(s) → Na1+(aq) + Cl1-(aq)

CaCl2(s) → Ca2+(aq) + 2Cl1-(aq)

B. Most ____________ compounds (except for acids which we will discuss in a later unit), dissolve in water as __________

molecules.

H2O

H2O

Electrolytic/Non-Electrolytic SolutionsA. A solute that __________ in water to give a solution of ions does conduct electric current and is called

an ______________.

1. Typically, ionic compounds will ____________ electrical current when ___________ in water.

2. Strong acids (which we will discuss in a later unit) also are __________________________.

B. A solute that dissolves in water to give a solution of _____________ does NOT conduct electric current is called a

______________________.

1. Typically, covalent compounds will NOT ____________ electrical current when _____________ in water.

C. A solute that dissolves mostly as molecules but _____________ as ions does (although not as well) conduct

electric current is called a _______________________.

1. Typically, ________________ (which we will discuss in a later unit) are generally weak electrolytes.


Learning Target:I can understand precipitation reactions.

Criteria for Success:I can predict whether a precipitate will form when solutions of soluble ionic compounds are combined.

I can write net ionic equations for precipitation reactions.

Precipitation ReactionsA. A ________________ reaction is a reaction in which __________ ions in separate solutions are mixed together to form an _____________ compound that settles out of solution as a ___________.

1. The insoluble compound that settles out is called a ________________.2. Use a reference chart of ______________ rules to determine which compounds will form ________________.

Which product will form a precipitate?(NH4)2S(aq) + Cd(NO3)2(aq) → NH4NO3(?) + CdS(?)

Net Ionic EquationsA. A _____ __________ ______________ includes only those compounds and ions that undergo a ______________ change in a reaction in an aqueous solution.

1. Ions that do ______ take part in a chemical reaction and are found in solution both before and after the reaction are ______________ _____.

Highlight the spectator ionsZn(NO3)2(aq) + (NH4)2S(aq) → ZnS(s) + 2NH4NO3(aq)

Zn2+(aq) + 2NO31-(aq) + 2NH4

1+(aq) + S2-(aq) → ZnS(s) + 2NH41+(aq) + 2NO3

1-(aq)

B. Use the following steps to _________ net ionic equations.1. First, convert the chemical equation into an overall ionic equation. All _________ ionic compounds are shown as ___________________ ions in solution. The _______________ are shown as solids. 2. Second, ____________ the _______________ ions on both sides of the equation.3. Third, write final net ionic equation without ________________ ions.


Learning Target:I can investigate factors that influence rates of dissolution.

Criteria for Success:I can list and explain three factors that affect the rate at which a solid solute dissolves in a liquid solvent.

The Solution ProcessA. Factors Affecting the Rate of at which a Solid Solute Dissolves in a Liquid Solvent

1. ________________________ the solvent.

2. ________________________ the solution.

3. ________________________ the surface area of the solute.

Mini LabsPart One—Effects of Temperature on the Rate of DissolutionProcedure:1. Obtain three beakers. In one beaker pour 200mL of hot water. In the second beaker pour 200mL of room temperature water. In the third beaker pour 200mL of cold water.2. AT THE EXACT SAME TIME, place one sugar cube in each of the beakers and start the time on a stopwatch.3. Record the amount of time required for the sugar cube to dissolve into a pile in each beaker.

Hot Water Room Temperature Water Cold Water

Time to Dissolve (s)

Part Two—Effects of Agitation on the Rate of DissolutionProcedure:1. Obtain two beakers. In one beaker pour 200mL of room temperature water. In the second cup pour 200mL of room temperature water. 2. AT THE EXACT SAME TIME, place one sugar cube in each of the cups and start the time on the stopwatch. Immediately begin stirring the solvent in the first beaker. Leave the second beaker alone. 3. Record the amount of time required for the sugar to completely dissolve in each beaker.

Agitated Cup Non-Agitated Cup


Part Three— Effects of Surface Area on the Rate of DissolutionProcedure:1. Obtain two beakers.In one beaker pour 200mL of room temperature water. In the second beaker pour 200mL of room temperature water. 2. Use a mortar and pestle to crush one sugar cube into a fine powder.3. AT THE EXACT SAME TIME, place one whole sugar cube into one beaker and pour the crushed sugar cube into the other, start the time on the stopwatch and immediately begin agitating each solvent. Do NOT crush the whole cube with the stirring rod. 4. Record the amount of time required for the sugar in each cup to completely dissolve.

Crushed/Powdered Whole Cube


Solutions

Unit 10 Page 7

Learning Target:I can distinguish between unsaturated, saturated, and supersaturated solutions.

I can investigate factors that influence solubilities.Criteria for Success:

I can distinguish among saturated, unsaturated, and supersaturated solutions.I can define solubility.

I can compare the effects of temperature and pressure on solubility.I can describe the effects of bonding and polarity on solubility.

Solubility

A. The __________________________ of a substance is the amount of that substance required to form a saturated solution

with a specific amount of solvent at a specified _____________________________.

1. A _________________________ solution is a solution that contains the maximum amount of dissolved solute.

2. An ____________________________ solution is a solution that contains less solute than a saturated solution

under the same conditions.

3. A ______________________________ solution is a solution that contains more dissolved solute than a saturated

solution contains under the same conditions.

Factors Affecting Solubility

A. _________________________ affects the solubility of gases in liquids.

1. An _____________________ in pressure will increase the solubility of the gas.

B. _________________________ affects the solubility of gases and solids in liquids.

1. An ___________________ in temperature will decrease the solubility of the gas.

2. An ___________________ in temperature will usually increase the solubility of a solid.

Interpreting Solubility Graphs (See Practice Problems Pg 3!!)

A. The line on the graph indicates the point at which you have a ___________________ solution of the solute indicated.

1. Any point below this line would indicate an _____________________ solution.

2. Any point above this line would still indicate a saturated solution, but one that contains ____________ solute

equal to the difference between the point above the line until the point on the line at a given temperature.

How Bonding Type Affects Solubility

A. The type of _______________________, ________________________, and ________________________ forces will also determine

solubility. “___________________________” is a rough but useful rule for predicting whether one substance will dissolve in

another.

1. Liquid solutes and solvents that are not soluble in each other are __________________________.

2. Liquids that dissolve freely in one another are said to be ______________________.


Learning Target:I can calculate the concentration of solutions in units of molarity.

Criteria for Success:I can calculate the concentration of a solution in units of molarity.

Concentration of Solutions

A. The ________________________ of a solution is a measure of the amount of ________________ in a given amount of

__________________.

1. A _______________ solution is considered to have a relatively _____________ amount of solute in a solvent.

2. A _________________ solution is considered to have a relatively ___________ amount of solute in a solvent.

B. ______________________ is the number of ________________ of solute in ___________ ________________ of solvent (Often this

solvent is water).

molarity(M) = _moles of solute_ Liters of solution

1. Often, we express molar concentrations, by putting the concentration in brackets [ ].

Example: The concentration of sodium chloride = [NaCl]


Content Objective:

I can use molarity to calculate the dilutions of solutions.

Criteria for Success:

I can perform three types of dilution calculations.

Dilutions

A. To save time and space in the laboratory, routinely used solutions are often purchased or prepared in

concentrated form, called ___________________ solutions.

1. ________________________ is added to achieve the molarity desired for a particular solution. This is known as

__________________________.

2. ______________________ with __________________ does not alter the numbers of moles of solute present.

3. Remember when diluting ___________________, always add __________________ to __________________.

B. When diluting solutions it is important to remember the number of __________________ does not change. We can set

up the following equation to express this idea.

V1M1 = V2M2


Learning Target:I can perform stoichiometric calculations involving concentrations of solutions.

Criteria for Success:I can solve the molarity equation for amount in moles.

I can use the amount in moles determined from the molarity equation to calculate moles, mass in grams, volume of gas, or number of particles of any other reactant or product in the reaction.

Solution Stoichiometry

A. The molarity equation can be rearranged to solve for __________________.

molarity(M) = __moles of solute__ liter of solution

B. Once you have determined the number of moles in the solution, you can use this to perform stoichiometry

calculations to determine amount in moles, mass in grams, volume of a gas, or number of particles of any other

reactant or product in the reaction using ________________________ _______________________.

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teachemrosinski.files.wordpress.com … · Web viewSolutions. Unit 10 Page 1. Learning Target: I can. describe the unique role of water in chemical and biological systems. Criteria