A student is investigating various types of matter based on a simplified model created in science class. The student examines the salad dressing bottle, noticing that the oily component and the vinegar component have separated. The herbs are also distinctly visible in the oil layer. How would the model help the student determine the classification of matter for the salad dressing?

Question

A If the oily layer can be physically removed from the vinegar, it must be a mixture. If the herbs can be physically removed, it must be a solution.If the oily layer can be physically removed from the vinegar, it must be a mixture. If the herbs can be physically removed, it must be a solution.
B If the oily layer can be physically removed from the vinegar, it must be a pure substance. If the herbs can be physically removed, it must be elemental.If the oily layer can be physically removed from the vinegar, it must be a pure substance. If the herbs can be physically removed, it must be elemental.
C If the oily layer can be physically removed from the vinegar, it must be a pure substance. If the herbs can be physically removed, it must be a compound.If the oily layer can be physically removed from the vinegar, it must be a pure substance. If the herbs can be physically removed, it must be a compound.
D If the oily layer can be physically removed from the vinegar, it must be a mixture. If the herbs can be visibly seen in the midst of the dressing, it must be a suspension.If the oily layer can be physically removed from the vinegar, it must be a mixture. If the herbs can be visibly seen in the midst of the dressing, it must be a suspension.
Question 2
A student has a sample of ocean water that they take to science class. What steps could be taken to determine to classify the ocean water as a suspension, solution, element, or compound?
Responses
A Examine the pH of the sample. If the pH is exactly neutral, it is a pure substance that is a compound.Examine the pH of the sample. If the pH is exactly neutral, it is a pure substance that is a compound.
B Evaporate the water. If salt is left behind, the sample is a mixture that can be defined as a solution.Evaporate the water. If salt is left behind, the sample is a mixture that can be defined as a solution.
C Let the sample settle. If the salt settles to the bottom, it is a mixture that is classified as a solution.Let the sample settle. If the salt settles to the bottom, it is a mixture that is classified as a solution.
D Observe the diffraction of light as it moved through the sample. If light does not scatter, it is a pure substance that is elemental.

Answer 1

Question 1:

The correct option is:

D If the oily layer can be physically removed from the vinegar, it must be a mixture. If the herbs can be visibly seen in the midst of the dressing, it must be a suspension.

Explanation: The separation of the oily and vinegar components indicates that the salad dressing is a mixture, as they can be physically separated. Additionally, if the herbs are visible and suspended in the dressing, this suggests that they are a part of a suspension, where larger particles are dispersed within the liquid but not dissolved.

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Question 2:

The correct option is:

B Evaporate the water. If salt is left behind, the sample is a mixture that can be defined as a solution.

Explanation: If ocean water is evaporated and leaves behind salt, this means that the salt was dissolved in the water, indicating that the ocean water is a solution. If the salt settles to the bottom, it suggests the formation of a different type of mixture (like a suspension), but because ocean water is typically considered a solution due to the dissolved salts and other substances, this option accurately describes the classification process.