SoLutions :

Properties of SolutionMs. Raihan

1

CA StandardsStd. 6a: Students know the definitions of solute and solvent.

Std. 6b: Students know how to describe the dissolving process at the molecular level by using the concept of random molecular motion.

Std. 6c: Students know temperature, pressure, and surface area affect the dissolving process.

Std. 6ASolution:

Solute:

Solvent:a homogeneous mixture of solute and solvent. (gas/liquid/solid)Homogeneous--of the same or similar nature or kindis the dissolved substance in a solution (lesser amt.) e.g. salt in salt water, sugar/CO2 in soda drinks

dissolving medium in a solution (greater amt.)e.g. water in salt water, water in soda

Like dissolves LikePolar and ionic solutes dissolve best in polar solventsEx: salts, sugars water, small alcohols, acetic acidNon-polar solutes dissolve in non-polar solventsEx: fats, steroids,waxes hexane, toluene, benzene

This is why oil and water do not mix!

Solute/Solvent relationship:

5

refers to movement of molecules

Kinetic Energy of these movements allows mixing of solute and solvent Diffusion

Kinetic Theory & Dissolving:

Salts in water pos. (+) and neg. (- ) ions separate and get surrounded by POLAR water molecules

breaks down into +/- ions and conducts electricity. Ex: Gatorade

does not break down and do not conduct electricity.Ex: Sugar solutionDissolution:

Electrolytes:

Non-Electrolytes:Std 6b: Solution at a molecular level:Dissolution

The ammeter measures the flow of electrons (current) through the circuit. If the ammeter measures a current, and the bulb glows, then the solution conducts.

If the ammeter fails to measure a current, and the bulb does not glow, the solution is non-conducting.Electrolytes vs. Nonelectrolytes

Pure waterTap waterSugar solutionSodium chloride solutionHydrochloric acid solutionLactic acid solutionEthanol solutionPure sodium chloride

Try to classify the following substances as electrolytes or nonelectrolytesELECTROLYTES:NONELECTROLYTES: Tap water (weak) NaCl solution HCl solution Lactic acid solution (weak)

Pure water Sugar solution Ethanol solution Pure NaCl

Answers to Electrolytes

Solubility Trendmax amt. of substance that dissolve at a specific temp.

Solubility:

supersaturatedTemperature & SolvationWhy do certain solute tend to dissolve better at a higher temperature?Kinetic theory more movement at higher temperature allows better mixing and diffusion.Gas dissolve best when:

Solids dissolve best when:

Solution is cold (temp)Pressure is high (pressure)

Heated (temp)Stirred (agitation)Grounded into smaller pieces (surface area)

Std. 6c: Factors affecting dissolving process

The solubility of the KNO3 increases as the temperature increases.Yb2(SO4)3 shows a decrease in solubility as the temperature increases, and NaCl shows the least change in solubility as temperature changes

Saturated solution has the maximum amount of solute dissolved. perfect solution

Unsaturated solution a solution that has LESS than the max amt. imperfect solution

Supersaturated solution has MORE than the max amt. --needs to be heatedsuper solutionTypes of Solutions: Lets Ethanol is a small polar alcohol. It will mix well with what type of solvent?

Water (polar)Hexane (non-polar)Propanol (polar)None of the abovee) A and C are correct

2. Salt in solutions conduct electricity because

It has a lot of kinetic EIt transfers electronsc) It dissociates into +/- ionsd) It creates a saturated solution3) A solution that has less than maximum amount of solute is called

saturatedsupersaturatedtrans-saturatedunsaturated4) Solubility of a gas increases when the pressure is _____ and temp is ______.

high and lowlow and highlow and lowhigh and highThe EndSolutions:

ReviewWhat is a solution?

What is a solute?

What is a solvent?

What is the solute/solvent relationship?

Ex of non-polar solute and solvent

a homogeneous mixture of solute and solvent

The dissolved substance in a solution

The dissolving medium

Like dissolves like

Fats and hexane

Ex of polar solute and solvent

What is the kinetic theory?

How does kinetic theory relate to solutions?

Kinetic energy from the movements allows

Salt and water

Movement of molecules

Movement of molecules in a solution allows mixing of solute and solvent.

DIFFUSION

Ex of polar solute and solvent

What is the kinetic theory?

How does kinetic theory relate to solutions?

Kinetic energy from the movements allows

Salt and water

Movement of molecules

Movement of molecules in a solution allows mixing of solute and solvent.

DIFFUSION

Solute and solvent mixes until

What is Equilibrium?

Equilibrium depends which two factors?

What is dissolution?

Equilibrium is reached

Equal distribution of solute and solvent in a solution

1) surface interactions 2) bond strengths

solute breaking down into ions mostly seen in salts

breaks down into + and ions and conducts electricity.

doesnt break down and do not conduct electricity.

has the maximum amount of solute dissolved

has less than the max amount of soluteWhat is an electrolyte?

What is a non-electrolyte?

What is a saturated solution?

What is an un-saturated solution?What is a super-saturated solution?

How do you make a super-saturated solution?

has more than the required amount of solute

heating the solution