Mixtures

A mixture of beads was placed in a container, as shown belo. The beads are of various sizes, and each one is made of plastic, glass, or steel. The mixture would be easy to separate because all the beads--- (5.5B)

• are less dense than water

• are solids

• have the same mass

• are attached to a magnet

A worker built a sidewalk and pressed some large salt particles into the concrete while it was still wet. When the concrete was dry, the worker washed the sidewalk with water. The picture below shows the sidewalk after it was washed. What most likely happened to the salt? (5.5C)

• It evaporated into a gas.

• It turned into concrete.

• It dissolved in the water.

• It turned into a solid.

When a powdered drink mix was added to water, the liquid turned orange. A student decided the taste was too strong, so he poured out half of the liquid and added more water. Which of the following most likely occurred when more water was added? (5.5C)

• The physical state changed.

• The orange color became lighter.

• The liquid had a sweeter taste.

• None of the above

A student made a mixture using equal amounts of salt and pepper. The salt grains were the same size as the pepper grains. What should the student do to most easily separate the pepper from the salt? (5.5B)

• Use a pair of tweezers to remove each grain of pepper

• Run a small magnet through the mixture to attract the pepper

• Put the mixture in water and filter the pepper out of the water

• Use a strainer with a fine wire screen to remove the pepper

A student adds 10 grams of four different powdered solids into four different beakers. The student then adds 100 mL of water to each beaker, stirs the mixtures, and allows them to sit for half an hour before recording observations. Which question is the student most likely trying to answer with this investigation? (5.5C)

• At what water temperature do the substances dissolve?

• How much water is needed to cause a substance to change state?

• What causes a substance to sink when put in water?

• Which substances dissolve in water?

Some people add sugar to their hot tea. Which property of the sugar remains the same when the sugar is in the tea solution? (5.5C)

• The taste of the sugar

• The size of the sugar crystals

• The color of the sugar

• The texture of the sugar

A student combined powdered paint with water to make a small amount of a blue liquid paint mixture. The student left the paint mixture in an open container. Several days later the student found the container and observed that changes had occurred. What most likely happened to the mixture? (5.5B)

• The container was empty after the mixture evaporated into the air.

• The paint evaporated, leaving only clear water in the container.

• The water evaporated, leaving only a dry blue solid in the container.

• The liquid paint mixture was lighter in color after some water evaporated.

For an investigation a student put 100 mL of water at room temperature into each of three beakers. Then the student added a coin to Beaker R, 3 g of a powdered drink mix to Beaker S, and 10 mL of lamp oil to Beaker T. The student stirred the contents of the beakers and then left them sitting on a lab table for 5 minutes. Which diagram shows what the student most likely observed in each of the beakers after 5 minutes? (5.5C)

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A beaker with 115 mL of solution has a temperature of 21 degrees Celsius. The solution contains 5 g of salt and 115 mL of water. Students added two ice cubes to the solution and stirred the solution with a stirring rod. Which properties of the solution changed as the ice cubes melted? (5.5C)

• The color and physical state of the solution

• The temperature, mass, and volume of the solution

• The volume, temperature, and mass of the salt in the solution

• The physical state and temperature of the solution

A student stirs 15 grams of each substance listed below into 200 milliliters of water to form four different mixtures. The student then tries to separate the water from each mixture by pouring the mixture through a kitchen tea strainer. Which mixture can the student separate most easily with the strainer? (5.5B)

• Salt and water

• Gravel and water

• Shampoo and water

• Sugar and water