During a demonstration, a teacher placed 20 mL of water, 10 mL of isopropyl alcohol (IPA), and 1 drop of blue food coloring into a test tube, capped the test tube, and inverted it 6 times. Next, she added 7 g of ammonium sulfate (AS), an ionic solid, to the test tube, capped the test tube, and vigorously shook it for 10 sec. Then, over the 15 sec period immediately following the shaking, the mix- ture in the test tube completely separated into 2 distinct liquid layers (see figure). The teacher asked each of 4 students to provide an explanation for what occurred in the test tube over the 15 sec period. Student 1 Over the 15 sec, the mixture separated into 2 layers because IPA is denser than water. The water layer was on top, and the IPA layer was on the bottom. The AS dissolved in the IPA only, because AS breaks apart into neutral molecules when dissolved in IPA. Blue food colouring is polar, so it dissolves in the water only. Student 2 Over the 15 sec, the mixture separated into 2 layers because water is denser than IPA. The IPA layer was on top, and the water layer was on the bottom. The AS dis- solved in the water only, because AS breaks apart into neutral molecules when dissolved in water. Blue food colouring is polar, so it dissolves in the IPA only. Based on the figure, 5 see after the shaking, would the contents of the test tube have been better classified as a heterogeneous mixture or a homogeneous mixture?
Correct answer: A. Heterogeneous, because the contents of the test tube varied in composition from one region to another.
A. Heterogeneous, because the contents of the test tube varied in composition from one region to another.
B. Heterogeneous, because the contents of the test tube were uniform in composition throughout.
C. Homogeneous, because the contents of the test tube varied in composition from one region to another.
D. Homogeneous, because the contents of the test tube were uniform in composition throughout.
Explanation
There are two types of mixtures: heterogeneous and homogeneous. Heterogeneous mixtures have visually distinguishable components, while homogeneous mixtures appear uniform throughout. The most common type of homogenous mixture is a solution, which can be a solid, liquid, or gas.
Last updated 3 September 2026

Question

During a demonstration, a teacher placed 20 mL of water, 10 mL of isopropyl alcohol (IPA), and 1 drop of blue food coloring into a test tube, capped the test tube, and inverted it 6 times. Next, she added 7 g of ammonium sulfate (AS), an ionic solid, to the test tube, capped the test tube, and vigorously shook it for 10 sec. Then, over the 15 sec period immediately following the shaking, the mix- ture in the test tube completely separated into 2 distinct liquid layers (see figure). The teacher asked each of 4 students to provide an explanation for what occurred in the test tube over the 15 sec period. Student 1 Over the 15 sec, the mixture separated into 2 layers because IPA is denser than water. The water layer was on top, and the IPA layer was on the bottom. The AS dissolved in the IPA only, because AS breaks apart into neutral molecules when dissolved in IPA. Blue food colouring is polar, so it dissolves in the water only. Student 2 Over the 15 sec, the mixture separated into 2 layers because water is denser than IPA. The IPA layer was on top, and the water layer was on the bottom. The AS dis- solved in the water only, because AS breaks apart into neutral molecules when dissolved in water. Blue food colouring is polar, so it dissolves in the IPA only. Based on the figure, 5 see after the shaking, would the contents of the test tube have been better classified as a heterogeneous mixture or a homogeneous mixture?

Correct answer: A. Heterogeneous, because the contents of the test tube varied in composition from one region to another.

A. Heterogeneous, because the contents of the test tube varied in composition from one region to another.
B. Heterogeneous, because the contents of the test tube were uniform in composition throughout.
C. Homogeneous, because the contents of the test tube varied in composition from one region to another.
D. Homogeneous, because the contents of the test tube were uniform in composition throughout.

Explanation

There are two types of mixtures: heterogeneous and homogeneous. Heterogeneous mixtures have visually distinguishable components, while homogeneous mixtures appear uniform throughout. The most common type of homogenous mixture is a solution, which can be a solid, liquid, or gas.

Last updated 3 September 2026

TestUstad · Accepted Answer

Heterogeneous, because the contents of the test tube varied in composition from one region to another.. There are two types of mixtures: heterogeneous and homogeneous. Heterogeneous mixtures have visually distinguishable components, while homogeneous mixtures appear uniform throughout. The most common type of homogenous mixture is a solution, which can be a solid, liquid, or gas.

TestUstad · Answer

Heterogeneous, because the contents of the test tube were uniform in composition throughout.

TestUstad · Answer

Homogeneous, because the contents of the test tube varied in composition from one region to another.

TestUstad · Answer

Homogeneous, because the contents of the test tube were uniform in composition throughout.

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