Gen. Chem. 2_2nd QT_1st LT

A solubility curve shows that 80 g of KNO₃ dissolves in 100 g of water at 50ºC. What happens if the solution is cooled to 30ºC, where solubility is only 45 g?

• 35 g of KNO₃ will crystallize

• 45 g of KNO₃ will crystallize

• 35 g of KNO₃ will dissolve more

• All solid will remain dissolved

Which factor most likely causes a decrease in solubility of a gas in water?

• Decreasing pressure

• Decreasing temperature

• Increasing pressure

• Stirring the solution

A saturated solution of NaCl at 40ºC is heated to 80ºC. What type of solution will it become?

• Supersaturated

• Unsaturated

• Saturated

• Concentrated

From a solubility curve, which substance is most affected by temperature changes?

• KCl

• NaCl

• KNO₃

• NH₃ gas

A student plotted solubility vs. temperature but noticed a sudden drop at 100ºC. What error most likely occurred?

• Added excess solvent

• Used impure solute

• The temperature was misread

• The solute decomposed at high temperature

Which operation will increase the molarity of a solution?

• Diluting with water

• Adding more solvent

• Evaporating some solvent

• Cooling the solution

A solution contains 10 g of NaCl dissolved in 90 g of water. What is the percent by mass of NaCl in the solution?

• 9%

• 10%

• 11.1%

• 8.9%

Two solutions of equal molarity but different solutes (NaCl and CaCl₂) are compared. Which has higher ion concentration?

• NaCl

• CaCl₂

• Both are equal

• Cannot be determined

A teacher asked students to prepare 1.0 M sugar solution using 342 g/mol sugar. How many grams are needed for 500 mL?

• 171 g

• 342 g

• 68.4 g

• 85.5 g

Which of the following solutions has the highest number of solute particles?

• 1 M glucose

• 1 M NaCl

• 1 M CaCl₂

• 1 M CH₃OH