Pure Substances and Mixtures test review

Madison's lab group is given a dish that contains sand, shells and water. How should they classify the substance they have been given?

• As a compound, because it contains several elements.

• As a pure substance, because it’s made up of various compounds.

• As a heterogeneous, mixture because it does not have the same uniform appearance or composition.

• As a homogeneous, mixture because it has the same uniform appearance and composition throughout.

Examine the models.

Which choice below correctly explains which model is a pure substance?

• Model 2 is a pure substance because it represents an element.

• Model 1 is a pure substance because it represents several elements.

• Model 3 is a pure substance because it represents one type of compound.

• Model 4 is a pure substance because it contains both elements and compounds.

Tags

NGSS.MS-PS1-1

The graph shows the composition of the air we breathe.

Which of the following statements correctly classifies the air we breathe?

• The air we breathe is an element because it is made of pure substances.

• The air we breathe is a compound because it is made of different pure substances.

• The air we breathe is a heterogeneous mixture because it has visibly different substances and phases.

• The air we breathe is a homogeneous mixture because it has different substances but the same appearance throughout.

Distilled water (H2O) can be made from tap water by removing dissolved minerals and various other chemicals. How should each type of water be classified?

• Tap water is a homogeneous mixture and distilled water is a pure substance.

• Tap water is a heterogeneous mixture and distilled water is a pure substance.

• Tap water is a pure substance while distilled water is a homogeneous mixture.

• Tap water and distilled water contain hydrogen and oxygen, therefore they are both pure substances.

The table below shows various solutions and their pH.

Which substance is considered an acid?

• Lye

• Borax

• Water

• Lemon lime soda

Use the image of the pH scale to answer the following question.

If Gastric Juice and Sodium Hydroxide (as shown in the pH scale above) are mixed in a beaker during a lab, what type of solution will result?

• a salt solution

• a neutral acid solution

• a more basic solution

• a more acidic solution

Tags

NGSS.MS-PS1-2

The image contains a list of common household cleaners and their pH levels. Cleaning agents are generally basic solutions. Which would make the best cleaning agent?

• Vinegar

• Mild Dish Soap

• Tub & Tile Cleaner

• Toilet Bowl Cleaner

Use the image to answer the following question. Based on the pH scale, which substance is more acidic than tomato juice?

• Milk

• Black coffee

• Lemon juice

• Baking soda

Sebastian has two beakers. The first beaker has 100 mL of water and a second beaker has 500 mL of water. In order to identify common physical properties between both substances, he heats both substances to 100oC. Sebastian notices that both substances begin to bubble. What physical property does this experiment provide evidence for?

• This experiment provides evidence of a change in the volume of the samples.

• This experiment provides evidence that the volume remains constant in the samples.

• This experiment provides evidence that the boiling point does change based on sample size.

• This experiment provides evidence that the boiling point is a property independent of the amount of water.

Tags

NGSS.MS-PS1-4

Marissa blows up balloons for a party. She decides how big or small to make each balloon. Why does the air that she blows into each balloon take up all the space inside the balloon?

• The particles of air have a strong attraction between each other and the balloon.

• The particles of air move freely, colliding with each other and the sides of the balloon.

• The particles of air move and increase in size when they have more space in the balloon.

• The particles of air move around and slide past one another and take the shape of the balloon.

Tags

NGSS.MS-PS2-5