Checkpoint #6 Review

What best represents Jose’s dependent (outcome) variable?

• The amount of ice cubes added to the bowl.

• The change in mass as the ice cubes melted in the bowl.

• The amount of time the ice cubes took to melt in the bowl.

• The change in temperature as the ice cubes melted in the bowl.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which statement best describes how Jose should present his findings?

• He should say the results prove factual.

• He should say the results are inconclusive.

• He should say the results support his hypothesis.

• He should say the results fail to support his hypothesis.

Which is true about the solubilities of substances tested?

• Potassium iodide has the greatest solubility at any temperature tested.

• At any temperature, potassium nitrate is more soluble than sodium chloride.

• The solubility of potassium chlorate was least affected by temperature change.

• Sodium nitrate is less soluble than potassium nitrate at any of the tested temperatures.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

A student stated that increasing the temperature of the solvent always allows much more solute to dissolve. Evaluate the student's statement based on the test results in the graph. Is her statement supported?

• No, solubility and temperature are unrelated to each other.

• Yes, solubility increases greatly with increased temperature.

• No, the solubility of some substances is not greatly affected by temperature.

• Yes, substances that are not soluble at low temperatures become soluble at higher temperatures.

Which test and evidence best supports the conclusion that their solution was saturated?

• Test A: the salt collects at the bottom of the beaker

• Test B: the temperature of the water increases as the salt dissolves.

• Test C: the pH of the water increases as the salt dissolves.

• Test D: the salt dissolves faster when the solution is stirred.

Tags

NGSS.MS-PS1-2

What is the best prediction of their results?

• It will be less than the starting mass because water has less mass than ice.

• It will be less than the starting mass because mass is lost during phase changes.

• It will be the same as the starting mass because mass does not change as ice melts.

• It will be greater than the starting mass, because the energy absorbed by the sample has mass.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS1-5

NGSS.MS-PS3-4

In Beaker 1, students observe crystals form and grow on the string as the water slowly evaporates. Which statement describes the changes taking place in Beaker 2?

• Both sugar and water are undergoing physical changes.

• Both sugar and water are undergoing chemical changes.

• Sugar is undergoing a physical change and water is undergoing a chemical change.

• Sugar is undergoing a chemical change and water is undergoing a physical change.

Tags

NGSS.MS-PS1-2

In Beaker 2, the solution slowly changes from almost colorless to a thick, dark-brown syrup as the water boils and an odor is produced. Which of the following is the best evidence that a chemical change occurred in beaker 2?

• The solution changed temperature.

• The solution in the beaker became thicker as it boiled.

• The solution gave off bubbles of gas when it was heated.

• The syrup has a different color, texture, and odor than sugar.

Tags

NGSS.MS-PS1-2

After the experiment, students compared the total mass of the substances that remained to the mass of the sugar-water solution they made at the beginning of the experiment. The mass of the products was less than the beginning mass of the solution. How could students change the experiment to show that it follows the Law of Conservation of Mass?

• Use a string that cannot absorb water in Beaker 1.

• Make the solutions with a smaller amount of water.

• Prevent Beaker 2 from boiling during the experiment.

• Trap and measure the mass of water that evaporated or boiled.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What information best supports the conclusion that these substances undergo a chemical change, not a physical change when they are mixed?

• Two different materials are mixed together.

• New atoms are created, some are destroyed.

• The number of reactants and products are the same.

• Bonds between atoms are broken and reformed in different ways.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5