Question

If you mix olive oil with water, the olive oil will float on top of the water. The density of water is \(1.00 \mathrm{~g} / \mathrm{cm}^{3}\) at room temperature. (a) Is the density of olive oil more or less than \(1.00 \mathrm{~g} / \mathrm{cm}^{3} ?\) (b) The density of olive oil in its liquid phase does vary with temperature. Do you think olive oil would be more dense or less dense at higher temperatures? Explain.

Short answer

The short answer is: (a) The density of olive oil is less than \(1.00 \mathrm{~g} / \mathrm{cm}^3\) as it floats on top of water. (b) At higher temperatures, olive oil would typically be less dense due to the expansion of the liquid as its molecules gain energy and move faster, causing it to take up a larger space with the same mass.

Step-by-step solution

Understand the Property of Density

Density is a property of matter defined as mass per unit volume. In simple terms, if you take an object with the same mass as another object but occupying less space (volume) in similiar conditions, we say it has higher density.

Part (a) - Comparing density of olive oil with water

As given, when we mix olive oil and water, olive oil floats on top of the water. Floating implies that the object on top has less mass per unit volume compared to the object submerged beneath it. In this case, the density of olive oil is less than the density of water. So, the answer to part (a) is that the density of olive oil is less than \(1.00 \mathrm{~g} / \mathrm{cm}^3\).

Part (b) - Temperature effects on olive oil's density

The density of a substance can depend on various factors like temperature or pressure. When most liquids are heated, their molecules gain energy and move faster, causing the substance to expand. As the volume of the liquid increases, its density reduces since it now takes up a larger space with the same mass. So, we can infer that olive oil's density would typically decrease with increasing temperature, and it would be less dense at higher temperatures.

Key concepts

Properties of Matter

Matter is anything that takes up space and has mass, and its characteristics are known as properties of matter. One key property is density, which is defined as mass per unit volume. Imagine two balls made of different materials. If they are both the same size, but one is heavier, the heavier one is denser. This is because it has more mass packed into the same volume.

Density is significant because it helps determine how substances interact with each other. For instance, when you mix two liquids like olive oil and water, the one with lower density will float on the one with higher density. This property allows us to visually understand comparative densities of different substances.

Understanding these basic properties helps in many practical applications, such as designing ships, cooking, or even creating layered drinks!

Effects of Temperature on Density

Temperature plays a crucial role in affecting the density of substances. Typically, as the temperature of a liquid increases, its molecules move faster and spread apart. This increase in the movement causes the substance to expand, thereby increasing its volume.

Since density is calculated as mass divided by volume, an increase in volume while the mass remains constant results in a decrease in density. So, when you heat olive oil, it becomes less dense because the heat causes it to expand. This is a typical behavior for most liquids, as heating generally decreases their density.

This principle is essential in various scientific and practical applications, from understanding weather patterns to refining cooking techniques like frying.

Comparing Densities

Comparing the densities of different substances can help predict how they will interact when mixed. For example, when olive oil is mixed with water and it floats, it indicates that its density is lower than that of water (<1.00 g/cm³).

This simple comparison is often used in identifying liquids and is fundamental in various areas of science and industry. It helps in understanding phenomena such as why ice floats on water or how hot air balloons rise.

In practical terms, knowing how to compare densities helps in everyday life too. For instance, it can aid in designing mixtures, determining buoyancy, and even in culinary practices where oil and water are often combined.