Mixtures & Solutions

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?

• 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?

• 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?

• 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.

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Some ways to separate mixtures are listed below.

A student is given a beaker containing gravel and water. Which of these ways could the student NOT use to separate the gravel from the water?

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