Which would NOT increase the rate at which a sugar cube dissolves?

• Reducing the amount of solvent

• Crushing the sugar cube

• Stirring the solution

• Heating the solvent

Tags

NGSS.MS-PS1-4

You can make a solute dissolve more quickly in a solvent by

• adding more solute.

• adding ice.

• heating the solvent.

• removing some solvent.

Tags

NGSS.MS-PS1-4

A solution that contains all of the solute it can hold at a given temperature is

• diluted.

• saturated.

• supersaturated.

• unsaturated.

The amount of solute that can be dissolved in a specific amount of solvent at a given temperature is its

• concentration.

• density.

• dilution.

• solubility.

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.MS-PS1-4

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.

Students in Ms. Alvarez’s science class are investigating how temperature, in degrees Celsius (C), affects the solubility of a compound in 100 milliliters (mL) of water. Ms. Alvarez provides the students with a graph that shows the solubility of a certain compound, as shown below.

She then tell the students that she will demonstrate how many grams (g) of the compound will dissolve in 100 mL of water at 40 C. Based on the information in the graph, which of the following is the best prediction of how many grams of the compound will dissolve at 40 C?

• 40 g

• 65 g

• 85 g

• 100 g

Tags

NGSS.MS-PS1-4

The solubility graph below shows the amounts of four substances that will dissolve in 100 grams of water at various water temperatures.

Which substance has 80 grams of solute dissolved in 100 grams of water at 50 C?

• Potassium Bromide

• Ammonium Chloride

• Potassium Chloride

• Lithium Hydroxide

Tags

NGSS.MS-PS1-2

A solution that is able to dissolve additional solute is best described as

• supersaturated.

• concentrated.

• saturated

• unsaturated.