50 mL of CH3CH2Br (bromoethane) and 50 mL of water are poured into a separatory funnel. Bromoethane is a water‑insoluble compound with a density of 1.460gmL . The funnel is stoppered and the mixture is shaken vigorously. After standing, two layers separate. Which substance is in which layer? Explain. Bromoethane is more dense than water. Water is added second. The top layer is bromoethane and the bottom layer is water. The top layer is water and the bottom layer is bromoethane. Bromoethane has a higher molar mass than does water. b) Into the same funnel is poured carefully 50 mL of hexane (density = 0.660 g/mL) so that the other two layers are not disturbed. The hexane forms a third layer. The funnel is stoppered, and the mixture is shaken vigorously. After standing, two layers separate. Which compound(s) are in which layer? The top layer contains: The bottom layer contains:

See explanation below

Explanation:

In this case, we can explain this in a very basic way.

We know that heavier objects will go always at the bottom when we are carrying two objects, one heavier than the other right?

In the same manner works the density of two liquids. In this case, we have a mix of water and bromoethane. Bromoethane is an organic compound and it's less polar than water which is extremely polar. When we mix these two liquids, we can see that both of them are insoluble, so no matter how much we shake the funnel, the liquids will not mix to form a solution.

Instead of that, both of them will be in the funnel, and they'll be gradually separating into two layers. The bromoethane has a higher density than water, this means that in the bottom layer we will have the bromoethane and in the top layer we will have the water.

In case you are wondering what happens if we added water first and then, the bromoethane?, it will happen the same, it does not matter the order you add the liquid, because density here is a very important factor, so when the water is added no matter which position, it will go to the top layer after the bromoethane is added.

Now when the hexane is added, it will form now three layers, and again, density plays an important factor. The higher density will go to the bottom, and the lowest to the top.

In this case, the order of layer will be:

Top layer: hexane (d = 0.66 g/mL)

Middle layer: water (d = 1 g/mL)

Bottom layer: bromoethane (d = 1.46 g/mL)

Hope this helps