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?

A bar magnet and a solenoid are kept beside each other. In which of the following cases current will not be produced?

Alcohols are carbon compounds containing a hydroxyl (OH) group. Alkenes are carbon compounds containing at least 1 carbon-carbon double bond (C=C). Dehydration (removal of H2O) of Alcohol W in the presence of phosphoric acid (H3PO4) produces H2O and a mixture of 4 alkenes (Alkenes 1-4) that each contain only 1 C=C bond: Dehydration of each of 3 other alcohols (Alcohols X, Y, and Z) produces H2O and 2 or more of Alkenes 1-4. Stu- dents studied the dehydration of each of these 4 alcohols, which are all liquids at 25°C. Which of the following statements gives the most likely reason that the test tube was cooled in ice water, as shown in Figure 1? The test tube was most likely cooled in ice water to more readily:

The atmosphere is made up of 4 distinct layers: the troposphere, stratosphere, mesosphere, and thermosphere. Different types of clouds form in the different layers depending on the pressure in the atmosphere and the ambient temperature. The cloud types include nimbus, stratus, cumulus, and cirrus. Figure 1 shows the location of the barriers of the atmosphere when the temperature and pressure are at an ideal condition for cloud formation. It also shows the different types of clouds formed at the different levels. Note: Clouds are formed mostly of water crystals, but can also contain particles of rock and dust. If pressure of 7 psi were sustained within the atmosphere, according to fig 1, which of the following types of clouds would likely form?

The following is a diagram of a sarcomere. How do the labelled parts change during muscle contraction?

Study the following graph and answer the question. For which of the following pairs of years the total exports from the three Companies together are equal?

Tollen's reagent, Ag+, is an oxidation agent. What are the products of Tollen's reagent reaction with the following molecule? Choose 1 answer: