Problem 42 - Chemistry and Chemical Reactivity

Question

Three liquids of different densities are mixed. Because they are not miscible (do not form a homogeneous solution with one another), they form discrete layers, one on top of the other. Sketch the result of mixing carbon tetrachloride \(\left(\mathrm{CCl}_{4}, d=1.58 \mathrm{g} / \mathrm{cm}^{3}\right),\) mercury \(\left(d=13.546 \mathrm{g} / \mathrm{cm}^{3}\right),\) and water \(\left(d=1.00 \mathrm{g} / \mathrm{cm}^{3}\right).\)

Step-by-Step Solution

Answer

Mercury (bottom), carbon tetrachloride (middle), water (top).

Step 1: Identify the density values

First, we need to identify the density of each of the liquids given in the problem. The densities are as follows:- Carbon tetrachloride (\(\mathrm{CCl}_4\)): \(1.58\, \mathrm{g/cm^3}\)- Mercury: \(13.546\, \mathrm{g/cm^3}\)- Water: \(1.00\, \mathrm{g/cm^3}\)

Step 2: Arrange the liquids by density

Next, arrange the three liquids in order of increasing density:- Water is the least dense with \(1.00 \ \mathrm{g/cm^3}\).- Carbon tetrachloride has a higher density of \(1.58 \ \mathrm{g/cm^3}\).- Mercury is the most dense with \(13.546 \ \mathrm{g/cm^3}\).

Step 3: Determine the layering sequence

The liquids will stack in layers according to their densities, with the least dense at the top and the most dense at the bottom: 1. Water will form the top layer, as it has the lowest density. 2. Carbon tetrachloride will form the middle layer, as it has a medium density. 3. Mercury will form the bottom layer, as it has the highest density.

Step 4: Sketch the mixture

Create a sketch of a container showing three distinct layers, from top to bottom: - The top layer is water. - The middle layer is carbon tetrachloride. - The bottom layer is mercury.

Key Concepts

Immiscible Liquids

When we talk about immiscible liquids, we refer to liquids that do not mix or blend into a single homogeneous solution. Each liquid keeps to its own space, forming distinct layers when combined with others. This immiscibility arises because of differing molecular structures and polarities, blocking any strong interactions between the different liquids.
For example, water and oil are classic immiscible liquids because of their diverse polar characteristics. While water is polar, oil is non-polar, and these differences cause them to separate when mixed.
Immiscible liquids are crucial in scientific experiments and industrial processes. Understanding their properties allows us to predict how they will behave when placed in the same container. In our case, the immiscible liquids are carbon tetrachloride, mercury, and water, each of which will settle into its own layer.

Layering of Liquids

When liquids are immiscible, they naturally form layers. The layering occurs based on their densities, a key physical property that determines how heavy an object is for its size.
In simpler terms, density is mass per unit volume. Higher density means heavier, and lower density means lighter.

• Heavier or denser liquids tend to sink to the bottom of a container.
• Lighter or less dense liquids rise to the top.

Individually, none of the layers will mix with the others. It's this characteristic that allows for precise separation of liquids, such as in oil-water separation techniques. When arranging them in our container, we find the densest liquid at the bottom and the least dense at the top.

Density Arrangement

The key to understanding how these immiscible liquids arrange themselves is density. The idea is simple: liquids with differing densities will form a stack of layers.
When we have carbon tetrachloride, mercury, and water:

• Water, with the density of 1.00 g/cm³, is the least dense.
• Carbon tetrachloride has a density of 1.58 g/cm³, slightly denser than water.
• Mercury tops the chart with a whopping 13.546 g/cm³.

Therefore, when placed in a container, mercury will naturally settle at the bottom, carbon tetrachloride in the middle, and water will float on top.

Liquid Density Comparison

Comparing liquid densities helps us predict how they will behave when mixed. Density comparison tells us not just about layering but also about the relative weight of different liquids in a set volume.
This property is vital in many scientific applications, such as determining buoyancy or predicting volcanic magma flows.
In our scenario, these comparisons inform us of how the liquids will layer. With given densities:

• Water, being the least dense, will always float above carbon tetrachloride and mercury.
• Carbon tetrachloride, with a higher density than water but less than mercury, will nestle between the two.
• And mercury, being the densest, will be stable at the bottom.

By examining these densities, we can efficiently visualize and execute experiments, showcasing how varying densities affect immiscible liquids.