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SoLutions : Properties of Solution. Ms. Raihan. CA Standards. Std. 6A. Solution: Solute: Solvent:. a homogeneous mixture of solute and solvent . (gas/liquid/solid) Homogeneous --of the same or similar nature or kind is the dissolved substance in a solution ( lesser amt. )
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SoLutions :Properties of Solution Ms. Raihan
Std. 6A Solution: Solute: Solvent: • a homogeneous mixture of solute and solvent. (gas/liquid/solid) Homogeneous--of the same or similar nature or kind • is the dissolved substance in a solution (lesser amt.) e.g. salt in salt water, sugar/CO2in soda drinks • dissolving medium in a solution (greater amt.) e.g. water in salt water, water in soda
Like dissolves Like • Polar and ionic solutes dissolve best in polar solvents • Ex: salts, sugars water, small alcohols, acetic acid • Non-polar solutes dissolve in non-polar solvents • Ex: fats, steroids,waxes hexane, toluene, benzene • This is why oil and water do not mix! Solute/Solvent relationship:
refers to movement of molecules • Kinetic Energy of these movements allows mixing of solute and solvent Diffusion Kinetic Theory & Dissolving:
Std 6b: Solution at a molecular level: Dissolution: Electrolytes: Non-Electrolytes: • 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 solution
Electrolytes vs. Nonelectrolytes 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.
Try to classify the following substances as electrolytes or nonelectrolytes… • Pure water • Tap water • Sugar solution • Sodium chloride solution • Hydrochloric acid solution • Lactic acid solution • Ethanol solution • Pure sodium chloride
Answers to Electrolytes NONELECTROLYTES: ELECTROLYTES: • Pure water • Sugar solution • Ethanol solution • Pure NaCl • Tap water (weak) • NaCl solution • HCl solution • Lactic acid solution (weak)
Solubility Trend • max amt. of substance that dissolve at a specific temp. Solubility: supersaturated
Temperature & Solvation Why do certain solute tend to dissolve better at a higher temperature? • Kinetic theory more movement at higher temperature allows better mixing and diffusion.
Std. 6c: Factors affecting dissolving process • Solution is cold (temp) • Pressure is high (pressure) • Heated (temp) • Stirred (agitation) • Grounded into smaller pieces (surface area) Gas dissolve best when: Solids dissolve best when:
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 solutionhas 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 heated…“super solution” Types of Solutions:
Let’s ✓ • 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 above e) A and C are correct 2. Salt in solutions conduct electricity because • It has a lot of kinetic E • It transfers electrons c) It dissociates into +/- ions d) It creates a saturated solution
3) A solution that has less than maximum amount of solute is called • saturated • supersaturated • trans-saturated • unsaturated 4) Solubility of a gas increases when the pressure is _____ and temp is ______. • high and low • low and high • low and low • high and high
What 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
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 Solute and solvent mixes until… What is Equilibrium? Equilibrium depends which two factors? What is dissolution?
What is an electrolyte? • What is a non-electrolyte? • What is a saturated solution? • What is an un-saturated solution? breaks down into + and – ions and conducts electricity. doesn’t break down and do not conduct electricity. has the maximum amount of solute dissolved has less than the max amount of solute
has more than the required amount of solute • heating the solution What is a super-saturated solution? How do you make a super-saturated solution?