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48 Cards in this Set
- Front
- Back
Compare the magnitude of the forces of the solvent and solute particles in a solution.
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The forces of attraction between the solvent and solute particles should be greater or equal in magnitude to the forces between solute-solute particles or solvent-solvent particles to ultimately form a solution.
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During the formation of a solution, three general energy processes occur. List these processes and list if they are endothermic or exothermic.
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1. Separating solute molecules (endothermic)
2. Separating solvent molecules (endothermic) 3. Attractive forces between solvent and solute molecules (exothermic) |
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True or false: Usually when solutions are spontaneously formed, they use energy.
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False. Spontaneous solution formation is usually exothermic.
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What is the difference between solute and solvent ?
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Solvent is usually the substance present in a larger amount than solute.
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Why does increasing the entropy of a system usually make the formation of the solution spontaneous ?
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Because by doing so the overall energy of the system is lowered.
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True or false: Dissolution is a chemical change.
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False. It is a physical change.
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Define a saturated solution.
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This is a solution that holds as much dissolved solute as possible at a specific temperature.
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Define an unsaturated solution.
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A solution where less than the maximum amount of solute is dissolved.
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Define a supersaturated solution.
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A solution that holds more solute than normally possible at a specific temperature.
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True or false: The more similar the inter molecular reactions between a solute and solvent, the more likely they will form a solution.
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True.
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What is the term for fluids that will mix with each other in all proportions ?
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Miscible.
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True or false: Hydrocarbons are polar molecules.
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False. Hydrocarbons are non-polar molecules.
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Identify this compound.
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Vitamin A.
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Why is Vitamin A not soluble in water ?
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Because it is a non-polar molecule.
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Identify this compound.
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Vitamin C.
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Why would vitamin C be soluble in water ?
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Because it is a polar compound.
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Which of these substances would dissolve either in CCl4 or water ?
1. C7H16 2. Na2SO4 3. HCl 4. I2 |
1. CCl4
2. Water 3. Water 4. CCL4 |
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What is the correlation between mass of a gas particle and its solubility in water ?
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The heavier the gas particle, the more soluble.
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What is the effect of pressure on gas solubility ?
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Increasing the pressure of a gas in a container with water will increase its solubility.
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Give Henry's law of gas solubility.
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S = Pk.
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What is the effect of temperature on solid solubility ?
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With an increase in temperature, the solubility of a gas also increases.
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What is the effect on solubility of Ce2(SO4)3 with an increase in temperature ?
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It becomes less soluble with an increase in temperature.
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What is the effect on gas solubility with an increase in temperature ?
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An increase in temperature causes the gas to become less soluble.
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Give the equation for expressing concentration by using- Mass Percentage.
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[(mass of A in solution)/(total mass of solution)] x 100.
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Give the equation for expressing concentration by using- Mole Fraction.
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(moles of component A)/(total moles of all components)
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Give the equation for expressing concentration by using- Molarity.
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(moles of solute)/(liters of solution).
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True or false: Molarity changes with a change in temperature.
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True. Because volume affects molarity and temperature affects volume we will see a change in molarity if the temperature changes.
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Give the equation for expressing concentration by using- Molality.
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(moles of solute)/(kg of solvent).
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True or false: Molarity changes with a change in temperature.
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False. Molality is only dependent on mass and moles, these variable do not change with a change in temperature.
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Which equation will you use to 'link' molality and molarity ?
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Density.
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An experiment calls for 36.0 g of a 5.00% aqueous solution of potassium bromide. Describe how you would make up such a solution.
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We make the solution by mixing 1.8 g KBr in 34.2 g water.
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Calculate the molarity of a solution of 0.0678g of NaCl in 25ml of total solution.
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0.0464 M.
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Iodine dissolves in a variety of organic solvents. For example, in methylene chloride, it forms an orange solution. What is the molality of a solution of 5.00 g iodine, I2, in 30.0 g of methylene chloride, CH2Cl2?
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0.657 m.
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A solution of iodine, I2, in methylene chloride, CH2Cl2, contains 5.00 g I2 and 56.0 g CH2Cl2. What is the mole fraction of each component in this solution?
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X(I2) = 0.0290
X(CH2Cl2) = 0.971 |
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A bottle of bourbon is labeled 94 proof, meaning that it is 47% by volume of alcohol in water. What is the mole fraction of ethyl alcohol, C2H5OH, in the bourbon? The density of ethyl alcohol is 0.80 g/mL.
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X(ethanol) = 0.22
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A 3.6 m solution of calcium chloride, CaCl2, is used in tractor tires to give them weight. The addition of CaCl2 also prevents water in the tires from freezing at temperatures above –20°C. What are the mole fractions of CaCl2 and water in such a solution?
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X(CaCl2) = 0.061
X(H2O) = 0.94 |
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A solution contains 8.89 × 10-3 mole fraction of I2 dissolved in 0.9911 mole fraction of CH2Cl2 (methylene chloride). What is the molality of I2 in this solution?
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0.106 m.
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Citric acid, HC6H7O7, is often used in fruit beverages to add tartness. An aqueous solution of citric acid is 2.331 m HC6H7O7. What is the molarity of the solution? The density of the solution is 1.1346 g/mL.
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1.827 M.
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What is the single factor that influences a solution's colligative properties ?
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The number of solute particles present.
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Name the four colligative properties.
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1. Vapour pressure lowering
2. Boiling point elevation 3. Freezing point depression 4. Osmotic pressure |
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Describe why the vapour pressure is lowered when a non-volatile solute is dissolved in a volatile solvent.
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The non-volatile solute makes it harder for the volatile molecules to escape the solution to enter the gas phase. This results in a lower number of molecules in the gas phase and thus the pressure is lowered.
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Give the equation of Raoult's law.
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Pa = Xa x Pa.
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Which variable is proportional to the increase in boiling point or decrease in freezing point of a solution ?
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Molality.
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Give the equation for osmotic pressure.
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Pi = MRT.
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Describe what will happen to a blood cell when the plasma is hypertonic.
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The cell will result in crenation, water flows out of the cell.
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Descrribe what will happen to a blood cell when the plasma is hypotonic.
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The cell will result in haemolysis, water will flow into the cell.
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What is a colloid ?
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A particle that is larger than an individual atom or molecule, but too small to be settled by gravity.
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What is the phenomenon called where colloids scatter rays of light ?
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The Tyndall effect.
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