Mixtures and Solutions Investigation

Which of the four solutions is the most concentrated?

• Solution 1

• Solution 2

• Solution 3

• Solution 4

Mark the two solutions that have the same concentration.

• Solution 1

• Solution 2

• Solution 3

• Solution 4

Epsom salts dissolves in water. People use a solution of Epsom salts and water to soak their sore feet. The Epsom salts is absorbed into the feet to sooth sore muscles. 200 g of Epsom salts was added to 2,000 mL of water to make a solution. How much Epsom salts would need to be added to 5,000 mL of water to make a solution of the same concentration?

• 50g

• 1000g

• 500g

• 200g

Two students made two solutions. Solution 1 was made with 50 mL of water and 12 g of a solid. Solution 2 was made with 100 mL of water and 24 g of the same solid. The students wanted to find out if one solution was more concentrated. They put the two solutions on a balance to compare the weight of the solutions. What is wrong with this procedure?

• They should have evaporated the liquids before weighing them.

• They should have used di erent solids to make the solutions.

• They should have measured volume not weight.

• They should have compared equal volumes of the two solutions.

A student makes a solution using 100 mL of water and 2 spoons of solid. One spoon of solid has a mass of 5 g. The student lets the solution sit until all the water evaporates. What is the mass after all the water has evaporated?

• 5g

• 8g

• 10g

• 100g

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A group is investigating the properties of four white substances as shown above. Their teacher gave them a cup labeled “Unknown” containing one of the four substances.

What can the group do to determine which substance is in the cup marked “Unknown?”

• Compare the taste of a very small amount of the known and unknown substances.

• Compare the color of the known and unknown substances.

• Dissolve each in water, let the water evaporate, and compare the shape of the crystals of the known and unknown substances

• Dissolve 5 g of each in water, let the water evaporate, and compare the number of the crystals of the known and unknown substances.

Tags

NGSS.MS-PS1-2

A group is investigating the properties of four white substances as shown above. Their teacher gave them a cup labeled “Unknown” containing one of the four substances.

What is another way they could determine what is in the cup labeled “Unknown?”

• Compare how many grams of each substance it takes to make a saturated solution.

• Time how long it takes the same amount of each substance to dissolve in the same amount of water.

• Compare the concentration of the solutions after dissolving a spoon of each substance in 50 mL of water.

• Dissolve 10 g of each solid in 50 mL of water and then compare the weights of the solutions.

Tags

NGSS.MS-PS1-2

A group is investigating the properties of four white substances as shown above. Their teacher gave them a cup labeled “Unknown” containing one of the four substances.

What is another way they could determine what is in the cup labeled “Unknown?”

• Compare how many grams of each substance it takes to make a saturated solution.

• Time how long it takes the same amount of each substance to dissolve in the same amount of water.

• Compare the concentration of the solutions after dissolving a spoon of each substance in 50 mL of water.

• Dissolve 10 g of each solid in 50 mL of water and then compare the weights of the solutions.

Tags

NGSS.MS-PS1-2

Look at the 5 cups of tea . Each has the same amount of tea, but a different amount of sugar added. Answer partws A & B:

a. There is no sugar at the bottom of cups A-C, but they taste different. Explain why they look the same but taste different.

b. There is sugar at the bottom of cups D and E. Explain why, then explain whether or not the tea in the two cups will taste the same or different.

Tags

NGSS.MS-PS1-2

A construction project is located near a pond. By accident, workers spilled a solid chemical powder that dissolved in the pond water. At first, the life in the pond seemed no different. But as summer arrived with no rain and lots of evaporation, there was less water in the pond. Dead fish began to appear. The number of dead fish increased as the hot, dry summer progressed and the pond continues to shrink.

Which pair of cups below represents the best model to compare the number of water particles, spilled chemical powder particles, and water level of the pond right after the spill and a few months later?

KEY: BLACK DOTS= 1,000 WATER PARTICLES WHITE DOTS=SPILLED CHEMICAL PARTICLES

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Tags

NGSS.MS-LS2-3

NGSS.MS-LS2-4

NGSS.MS-PS1-2