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Henri93
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The compositions of the solvent and the solute determine whether a substance will dissolve.
What makes it dissolve?
Stirring (agitation), temperature, and the surface area of the dissolving particles determine how fast the substance will dissolve.
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It's important to realize, however, that agitation (stirring or shaking) affects only the _____
- rate at which a solid solute dissolves.
- It does not influence the amount of solute that will dissolve.
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The more surface area of the solute that is exposed, the faster the _______.
rate of dissolving
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If you add 36.0 g of sodium chloride to 100 g of water at 25°C, all of the 36.0 g of salt dissolves. But if you add one more gram of salt and stir, no matter how vigorously or for how long, _______________
only 0.2 g of the last portion will dissolve.
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Temperature affects the solubility of solid, liquid, and gaseous solutes in a solvent; both _______ __ __________ affect the solubility of gaseous solutes.
temperature and pressure
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Gas solubility increases as the partial pressure of the gas above the solution ______.
increases
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Molarity (M) is the number of moles of solute dissolved in one liter of solution. To calculate the molarity of a solution, divide
the moles of solute by the volume of the solution.
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Diluting a solution reduces the number of moles of solute per unit volume, but the total number of moles of solute in solution does not change.
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Moles of solute = M1 × V1 =
M2 × V2
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The concentration of a solution in percent can be expressed in two ways: as the ratio of the volume of the solute to the volume of the solution or as the ratio of the mass of the solute to the mass of the solution.
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Three important colligative properties of solutions are vapor-pressure lowering, boiling-point elevation, and freezing-point depression.
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The decrease in a solution’s vapor pressure is proportional to the number of particles the solute makes in solution
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The freezing point of a solution is lower than the freezing point of the .
pure solvent
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The magnitude of the freezing-point depression is proportional to the number of solute particles dissolved in the solvent and does not depend upon their identity.
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The magnitude of the boiling-point elevation is proportional to the number of solute particles dissolved in the solvent.
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The unit molality and mole fractions are two additional ways in which chemists express the concentration of a solution. The unit molality (m) is the number of moles of solute dissolved in 1 kilogram (1000 g) of solvent. Molality is also known as molal concentration.
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The mole fraction of a solute in a solution is the ratio of the moles of that solute to the total number of moles of solvent and solute
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The magnitudes of the freezing-point depression (ΔTf) and the boiling-point elevation (ΔTb) of a solution are directly proportional to the molal concentration (m), when the solute is molecular, not ionic.
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ΔTf = Kf × m
ΔTb = Kb × m
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