Chemistry XII Unit 1 Questions: 50 Time Limit: 50 minutes Passing Score: 60% Start Quiz Chemistry XII Unit 1 Question 1 of 50 What is a solution? A heterogeneous mixture A homogeneous mixture of two or more substances A pure substance A compound Which component is present in larger amount in a solution? Solute Solvent Both equal Cannot determine What is molarity defined as? Moles of solute per kg of solvent Moles of solute per liter of solution Mass of solute per liter Moles of solvent per liter What is molality defined as? Moles of solute per liter of solution Moles of solute per kg of solvent Moles of solvent per kg Mass percentage Which colligative property is used for determining molar mass of biomolecules? Boiling point elevation Freezing point depression Osmotic pressure Vapor pressure lowering What is Raoult's law? Vapor pressure of solution equals mole fraction of solute Partial vapor pressure of component equals product of vapor pressure of pure component and its mole fraction Boiling point increases with solute addition Freezing point decreases with solute What is relative lowering of vapor pressure equal to? Mole fraction of solvent Mole fraction of solute Molarity Molality What is the formula for mole fraction of component A? nA divided by total moles Mass of A divided by total mass Moles of A times 100 Volume of A divided by total volume What happens to boiling point when non-volatile solute is added? Decreases Remains same Increases Becomes zero What is the unit of molal elevation constant Kb? K K kg per mol mol per kg L per mol What is the formula for boiling point elevation? Delta Tb equals Kb times m Delta Tb equals Kb divided by m Delta Tb equals m divided by Kb Delta Tb equals Kb plus m What happens to freezing point when solute is added? Increases Remains same Decreases Becomes negative What is the unit of molal depression constant Kf? K K kg per mol mol per kg kg per K What is the formula for freezing point depression? Delta Tf equals Kf times m Delta Tf equals Kf divided by m Delta Tf equals m divided by Kf Delta Tf equals Kf minus m What is osmosis? Flow of solute from lower to higher concentration Flow of solvent from lower to higher concentration through semipermeable membrane Mixing of two liquids Evaporation of solvent What is osmotic pressure? Pressure required to start osmosis Excess pressure needed to stop osmosis Atmospheric pressure Vapor pressure What is the formula for osmotic pressure? Pi equals CRT Pi equals C divided by RT Pi equals RT divided by C Pi equals C plus RT What are isotonic solutions? Solutions with same molarity Solutions with same osmotic pressure Solutions with same volume Solutions with same mass What is hypertonic solution? Solution with lower osmotic pressure than blood Solution with same osmotic pressure as blood Solution with higher osmotic pressure than blood Pure water What is hypotonic solution? Solution with higher osmotic pressure than blood Solution with same osmotic pressure as blood Solution with lower osmotic pressure than blood Concentrated salt solution What is the osmotic pressure of normal saline solution equivalent to? 0.5 percent mass by volume NaCl 0.9 percent mass by volume NaCl 1.5 percent mass by volume NaCl 2.0 percent mass by volume NaCl What are colligative properties? Properties depending on nature of solute Properties depending only on number of solute particles Properties of solvents only Properties of pure substances Which is NOT a colligative property? Vapor pressure lowering Boiling point elevation Density Osmotic pressure What is mass percentage? Mass of component divided by total mass times 100 Mass of solute per liter Moles per kg Volume percentage What is volume percentage? Volume of component divided by total volume times 100 Volume per mass Moles per liter Mass per volume What is parts per million (ppm)? Number of parts of component per million parts of solution Moles per million liters Mass per million kg Percentage divided by 10000 What is ideal solution? Solution obeying Raoult's law at all concentrations Solution with maximum deviation Pure substance Concentrated solution What is positive deviation from Raoult's law? Vapor pressure lower than expected Vapor pressure higher than expected No change in vapor pressure Follows Raoult's law exactly What is negative deviation from Raoult's law? Vapor pressure higher than expected Vapor pressure lower than expected No deviation Maximum vapor pressure Which mixture shows positive deviation? Ethanol and water Acetone and chloroform Ethanol and acetone Nitric acid and water Which mixture shows negative deviation? Ethanol and cyclohexane Acetone and carbon disulfide Chloroform and acetone Benzene and toluene What is azeotropic mixture? Mixture boiling at constant temperature with fixed composition Pure substance Mixture with varying boiling point Heterogeneous mixture What is minimum boiling azeotrope? Shows negative deviation Shows positive deviation Pure substance Follows Raoult's law What is maximum boiling azeotrope? Shows positive deviation Shows negative deviation Pure substance Ideal solution What is an example of minimum boiling azeotrope? 95.5 percent ethanol and 4.5 percent water 68 percent HNO3 and 32 percent water Pure ethanol Pure water What is an example of maximum boiling azeotrope? Ethanol-water 68 percent HNO3 and 32 percent water Acetone-ethanol Benzene-toluene What is Henry's law? Solubility of gas is directly proportional to partial pressure of gas Solubility inversely proportional to pressure Solubility independent of pressure Solubility proportional to temperature What is the mathematical form of Henry's law? p equals KH times x p equals x divided by KH x equals KH times p KH equals p times x What happens to solubility of gas with increase in temperature? Increases Decreases Remains same Becomes zero What happens to solubility of gas with increase in pressure? Decreases Remains same Increases Becomes zero Why are aquatic species more comfortable in cold water? More dissolved oxygen Less dissolved oxygen Higher temperature Lower pressure What is van't Hoff factor (i)? Ratio of normal molar mass to observed molar mass Ratio of observed molar mass to normal molar mass Moles of particles produced Association constant For dissociation, van't Hoff factor is: Less than 1 Equal to 1 Greater than 1 Zero For association, van't Hoff factor is: Greater than 1 Equal to 1 Less than 1 Infinite What is the modified formula for osmotic pressure for electrolytes? Pi equals CRT Pi equals iCRT Pi equals CRT divided by i Pi equals i divided by CRT What is degree of dissociation (alpha)? Fraction of molecules that dissociate Total molecules Number of ions formed Association constant What is relation between van't Hoff factor and degree of dissociation? i equals 1 plus alpha times (n minus 1) i equals 1 minus alpha i equals alpha times n i equals n minus alpha What is the Kf value for water? 0.52 K kg per mol 1.86 K kg per mol 5.12 K kg per mol 2.53 K kg per mol What is the Kb value for water? 1.86 K kg per mol 0.52 K kg per mol 2.53 K kg per mol 5.12 K kg per mol Which solvent has highest Kf value? Water Benzene Cyclohexane Chloroform Previous Next Submit Quiz Want to save your progress? Create an account or log in to track your quiz scores! Register/Login