Formative 6AB: Properties of Solutions and Rate of Reactions

A student sets up an experiment to test the factors that affect the solubility of sodium chloride. The student places 5.0g of sodium chloride in four beakers containing 250 mL of water. The student places each beaker on a different hot plate and heats them to the following temperatures:

Beaker A: 30°C

Beaker B: 40°C

Beaker C: 50°C

Beaker D: 60°C

In which beaker would the sodium chloride dissolve at the fastest rate?

• Beaker B

• Beaker C

• Beaker D

• Beaker A

Answer explanation

Remember the warmer the solvent the faster the solute can dissolve.

Tags

SPS6.b

Franklin tests three solutions with a conductivity tester, as shown in the picture. He tests a salt solution, a sugar solution, and an alcohol solution. Which solution, if any, conducts electricity, and why?

• The salt solution conducts electricity because it has salt ions that carry electricity in water.

• 
  The sugar solution conducts electricity because it has sugar ions that carry electricity in water.

• The alcohol solution conducts electricity because it has alcohol ions that carry electricity in water.

• None of the solutions conduct electricity because they do not have ions that carry electricity in water.

Answer explanation

Remember that ionic bonds conduct electricity when dissolved.

Tags

SPS6.a

The graphic shows an investigation being performed by four students. Each student will pour 10 grams of sugar into 100 milliliters of water into his or her container. They will stir the water gently for 20 seconds. Which student's sugar will most likely dissolve the fastest?

• Jennie

• Al

• Adrianne

• Marcus

Answer explanation

Remember higher temperatures and stirring increase the rate in which things can dissolve.

Tags

SPS6.b

If you wanted to decrease the dissolving rate of a solute that is a solid (salt) in a solvent that is a liquid (water), which of the following would you do?

• use the smallest pieces of solute you can find

• put the water on a hot plate first

• put the water in the freezer until it reached 35 degrees Fahrenheit

• stir the water vigourusly until all the solute was dissolved

Answer explanation

Remember that cold slows reactions

Tags

SPS6.a

Sam wants to dissolve a drink mix quickly before she goes to school. She adds 2 teaspoons of the drink mix to a glass that contains 8 ounces of room-temperature water. What could Sam do that would best help to speed up the dissolving?

• She could stir the water after adding the drink mix.

• She could chill the water before adding the drink mix.

• She could add the drink mix to a container with less water.

• She could add more of the drink mix to the container of water.

Answer explanation

Stirring helps speed up the mixing process.

Tags

SPS6.b

Simone conducted an experiment in her physical science class. She used a lightbulb, a battery, three wires, and an unknown solution to make a circuit. She made the circuit by connecting one wire between the battery and lightbulb, one wire from the lightbulb to the unknown solution, and the last wire from the unknown solution to the battery. Once the circuit was complete, the lightbulb lit up brightly. What was the unknown solution that helped conduct the electricity in Simone's circuit?

• a basic solution because a base will fully ionize in solution and has a high conductivity

• 
  a salt solution because salt will fully ionize in solution and has a high conductivity

• an acidic solution because an acid will fully ionize in solution and has a high conductivity

• a sugar solution because sugar will fully ionize in solution and has a high conductivity

Answer explanation

Remember that salt is an ionic bond and therefore conducts electricity when made into an aqueous solution.

Tags

SPS6.a

Which of the following will increase the solubility of salt in a given amount of water?

• An increase in the amount of salt

• A decrease in the amount of salt

• An increase in temperature

• A decrease in temperature

Answer explanation

Increasing the temperature allows the particles to break down more easily.

Tags

SPS6.b

Salt is added to a flask of water. The flask is sealed and shaken for several minutes. After being shaken, NaCl is still floating around in the water. What can be done to allow more NaCl to dissolve in the water?

• Heat up the solution.

• Continue shaking the solution.

• Expose the solution to air. 

• Cool down the solution.SPS

Tags

SPS6.a

Which of the following combinations would create the fastest chemical reactions?

• a whole antacid tablet and vinegar at 25 degrees Celsius

• a whole antacid tablet and vinegar at 50 degrees Celsius

• a crushed antacid tablet and vinegar at 25 degrees Celsius

• 
  a crushed antacid tablet and vinegar at 50 degrees Celsius

Tags

SPS6.b

Isabella decided to conduct an experiment to determine whether stirring affects the rate at which an antacid dissolves. She predicted that the faster she stirred, the less time it would take the antacid to dissolve. Based on the data in the table, it can be stated that the data

• is biased.

• supports the hypothesis.

• does not support the hypothesis.

• has no relationship to the hypothesis.

Tags

SPS6.b