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Solutions. What is a Solution. A solution is a homogeneous mixture. What a solutions made of. Solutions consist of two parts a solute and a solvent The solute is the material that is being dissolved The solvent is the material that the solute is being dissolved into Solubility
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What is a Solution • A solution is a homogeneous mixture
What a solutions made of • Solutions consist of two parts a solute and a solvent • The solute is the material that is being dissolved • The solvent is the material that the solute is being dissolved into • Solubility • Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent.
How do we Measure Solubility • The solubility of a solute in a solvent at a particular temperature is the number ofgrams of the solute necessary to saturate 100gm of the solvent at that temperature
What factors affect solubility • There are four factors that have an effect on solubility • Temperature • Nature of solute or solvent • Pressure • Particle size
Temperature • With solids and liquids solubility increases as temperature increases because particles are hitting each other more often • With gasses solubility decreases as temperature increases because the higher kinetic energy of the materials causes the particles to escape into the atmosphere
Temperature & the Solubility of GasesThe solubility of gases DECREASES at higher temperatures
Nature of solvent and solute • The key phrase to remember here is “Like Dissolves Like” • Polar solvent dissolves polar solutes • Non-polar solvent dissolves non-polar solutes
Pressure • With liquids and solids pressure has very little to do with solubility because the particles are already close together • With gasses the higher the pressure the higher the solubility because you are putting more particles in a closer proximity to one another
Particle size • Particle size does not affect the amount of a solute that will go into solution but it does affect the speed at which something goes into solution. • The smaller the particle size the faster it goes into solution because it has increase surface area and thus more material open to react
Concentration • The amount of a substance per defined space. Concentration usually is expressed in terms of mass per unitvolume • The are 4 way to express concentration of a solution • Molarity(M) • Molality (m) • Mass percent • Mole Fraction
Molarity(M) • Molarity is the number of moles of solute dissolved in one liter of solution. The units, therefore are moles per liter, specifically it's moles of solute per liter of solution. • molarity = moles of solute liter of solution
Molality (m) • the molality, m of a solvent/solute combination is defined as the amount of solute in molesnsolute, divided by the mass of the solvent, msolvent (not the mass of the solution)
Mass Percent • The mass percent is a calculation of the amount of what part of the mass of the solution comes the solute • (mass solute / mass of solution) * 100
Mole Fraction • Mole Fraction is a comparison of the number of moles of a solute in a solution to the total number of moles of solution • moles solute / total moles solution
Suppose you have 0.500 M sucrose stock solution. How do you prepare 250 mL of 0.348 M sucrose solution ? Concentration 0.500 M Sucrose 250 mL of 0.348 M sucrose Dilution When a solution is diluted, solvent is added to lower its concentration. The amount of solute remains constant before and after the dilution: moles BEFORE = moles AFTER C1V1 = C2V2 A bottle of 0.500 M standard sucrose stock solution is in the lab. Give precise instructions to your assistant on how to use the stock solution to prepare 250.0 mL of a 0.348 M sucrose solution.