AP Chem

You know that a substance has dissolved when it-

• becomes a solid
• produces condensation and has water droplets 
• spreads evenly throughout a liquid

At 30'C, which substance has the lowest solubility?

• KNO3

• KBr

• NaCl

• Yb2(SO4)3

A homogeneous mixture is the same thing as...

• a solution

• a heterogeneous mixture

• a compound

• an element

Which of the following usually makes a substance dissolve faster in a solvent?

• adding more solvent to the solution

• increasing the particle size of the solute

• lowering the temperature

• decreasing the number of particles

Tags

NGSS.HS-PS1-5

If a material does NOT dissolve in a liquid, it is said to be___________________

• soluble

• insoluble

• partly soluble

• partly insoluble

Three 10 g samples of sugar are represented below.

Sample A dissolves in water more slowly than sample B.

Sample B dissolves more slowly than sample C.

Which of the following best explains why sample A dissolves more slowly than the other two?

• It has the most volume.

• It has the smallest surface area.

• It has the largest number of sugar molecules.

• It has the fewest bonds between sugar modules.

Tags

NGSS.MS-PS1-2

A technican prepared a solution by heating 100 mL of distilled water while adding KCl crystals until no more KCl would dissolve. She then capped the clear solution and set it aside on the lab counter. After several hours she noticed the solution had become cloudly and some solid had settled to the bottom of the flask. Which statement best describes what happened?

• As the solution cooled, evaporation of water increased the KCl concentration beyond its solubility.

• Water molecules, trapped with the KCl crystals, were released after heating.

• At lower temperatures the solubility of KCl decreased and recrystallization occurred.

• At increased temperatures the solubility of KCl increased and remained too high after cooling.

Tags

NGSS.HS-PS1-5

A student pours mineral salts into a bottle of cold water. Which of the following best explains why shaking the bottle will affect the dissolving rate of the salt?

• Shaking exposes the salts to the solvent more quickly.

• Shaking helps more water evaporate.

• Shaking equalizes the water temperature.

• Shaking causes more ions to precipitate out of solution.

Tags

NGSS.HS-PS1-5

State whether the following compound is soluble or insoluble.  calcium carbonate CaCO₃ 

• soluble
• insoluble

State whether the following compound is soluble or insoluble. potassiun bromide KBr

• Soluble
• Insoluble