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Destiny is making a nutrient solution to use in her garden. She has to dissolve 1 cup of plant feed powder in 2 L of water. First, she places the powder in a watering can. Then she adds the water. Which of the following actions would most likely dissolve the powder the fastest?

• shaking the watering can vigorously

• stirring the solution in the watering can slowly

• tilting the watering can carefully from side to side

• setting the watering can down and leaving it alone

DeShawn is getting a new fish tank ready for the fish he plans to buy. He has to dissolve salt crystals in the water. What would be the best thing to do to help the crystals dissolve quickly?

• heat the salt crystals

• crush the salt crystals

• cool the water in the tank

• use the largest salt crystals

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Mrs. Lopez is a chemist who is studying salt crystals. She wants to slow the rate at which the crystals dissolve in a solution of water. What could she do to slow the dissolving rate?

• Crush the salt.

• Stir the solution.

• Heat the solution.

• Cool the solution.

Tags

NGSS.MS-PS1-4

A solution is formed when one substance is dissolved in another. Mae has a solution in which water is the solvent. Which of these could be the solute?

• oil

• pebbles

• sand

• sugar

Andrea created a solution by adding food coloring to water. Her solution is also a mixture. Which of these is true of all solutions?

• They are all liquids.

• They all include water.

• The parts of all solutions are evenly mixed.

• The substances are always permanently combined.

Mario was testing a mystery liquid to see how fast other items dissolved in it.  He used a controlled sample at room temperature (25 degrees Celsius) and added a dissolvable powder, then timed how long it took to completely dissolve.  He cooled some of the liquid to 10 degrees Celsius, put it in Jar A and placed the dissolvable powder in it, then timed how long it took the powder to dissolve.  Then he warmed some of the mystery liquid to 50 degrees Celsius, put it in Jar B and added the same amount of dissolvable powder as he did to Jar A, and then measured how long it took the powder to dissolve. Compare the time it took for the powder to dissolve in jars A & B verse the controlled sample.

• Faster for both Jar A and Jar B

• Faster for Jar A but slower for Jar B

• Slower for Jar A but faster for Jar B

• Slower for both Jar A and Jar B

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

A group of students are investigating how certain items dissolve in water.  Each child adds a 10g sample of each item to a container with 100mL of water that was heated to 50 degrees Celsius. Each child then stirs the water for 2 minutes.  The table below shows the items that were tested.  Which student would have a clear liquid with all of the item dissolved?

• Josh

• Nehemiah

• Deajah

• Christina

Tags

NGSS.MS-PS1-2

Nelson was going to bake cookies.  His recipe called for water and oil.  He decided that he would measure both at the same time. First, he put ½ a cup of water and then he put ¼ cup of cooking oil into a glass measuring cup. He stirred to mix the two liquids.  When he was ready to add it to dry ingredients, he noticed the oil and water had separated into two layers.

 

Why did the liquid separate into two layers?

• It was not stirred enough

• There was not enough water

• Oil does not dissolve in water

• The oil and water were not the same temperature

Tags

NGSS.MS-PS1-2

Carlos has a container that contains thousands of mixed glass beads, iron beads, and foam beads of different shapes and sizes. Which of the following is the best way to separate them?

• The glass and foam beads will float, so she could add water to the container and the glass and foam will float to the top. The iron beads will sink.

• The iron beads are magnetic, so she could separate the glass from the iron with a strong magnet. The foam beads will float to the top and the glass will sink.

• The iron beads might be heavier, so she could shake the container until the iron beads settle to the bottom. The glass and foam will float to the top.

• The iron beads are smaller, so she could pour the beads through a strainer and the glass beads will separate. The foam will sink to the bottom.

Four students; Cesar, Angelica, Hank, and Laurie made different mixtures. They decided that they would race to see whose mixture could be separated the fastest by sifting through a filter.  Whose mixture can most easily be separated using sifting? 

• Angelica's

• Cesar's

• Hank's

• Laurie's