Problem 23 - Chemistry: An Atoms-Focused Approach

Question

Give three properties that enable a person to distinguish between table sugar, water, and oxygen.

Step-by-Step Solution

Answer

Question: Name three properties that can help a person distinguish between table sugar (sucrose), water (H2O), and oxygen (O2). Answer: The three properties that can help a person distinguish between table sugar, water, and oxygen are: 1) their state of matter at room temperature, 2) taste, and 3) solubility in water.

Step 1: Property 1: State of matter at room temperature

At room temperature (approximately 25°C), table sugar is a solid, water is a liquid, and oxygen is a gas. This difference in states of matter at room temperature is an easy way to identify these three substances.

Step 2: Property 2: Taste

By using our sense of taste, we can also distinguish these substances. Table sugar is sweet, water has no taste, and oxygen is tasteless (although it is not safe to taste pure oxygen as it can be dangerous). This difference in taste is another way to identify each substance.

Step 3: Property 3: Solubility in water

The solubility of these substances in water can be another distinguishing property. Table sugar is soluble in water, which means it will dissolve when mixed with water. Water, of course, is itself a liquid and would just mix with more water. Oxygen is insoluble in water, which means it will not dissolve when mixed with water, and will instead form bubbles as it escapes the solution.

Key Concepts

States of Matter

Matter can exist in one of three primary states: solid, liquid, and gas. The state of matter for a substance at room temperature is a common property used to differentiate between materials, such as table sugar, water, and oxygen.

• Table sugar is a solid at room temperature. This means it maintains a fixed shape and volume. Solids, like sugar, do not flow unless under certain conditions like melting.
• Water, at the same room temperature, is a liquid. Unlike solids, liquids have a definite volume but take the shape of their container, allowing them to flow and spread.
• Oxygen is a gas, further differing from solids and liquids as it expands to fill the volume and shape of its container entirely. Gases like oxygen are less dense and invisible under normal conditions.

Understanding these states of matter helps us to categorize and make sense of the properties of various materials we encounter daily.

Solubility

Solubility is a measure of how much of a substance can dissolve in a given solvent at a specific temperature, typically water. It is another useful property to distinguish substances like sugar, water, and oxygen.

• Table sugar: Highly soluble in water. This means sugar will dissolve and mix uniformly in water, creating a homogeneous mixture.
• Water: The universal solvent. Water does not dissolve in itself but is used as the medium in which many other substances dissolve.
• Oxygen: Insoluble or only slightly soluble in water. Instead of dissolving, oxygen will escape as bubbles when mixed with water.

Understanding solubility is crucial in fields such as chemistry and environmental science, as it influences how substances interact with each other in a solution.

Taste

Our sense of taste allows us to detect different flavors, which can help in identifying substances like sugar, water, and oxygen, although caution should be taken with non-edible substances:

• Table sugar: Known for its sweet taste, sugar can be discerned immediately through flavor, making it easy to identify through tasting.
• Water: Typically described as tasteless, pure water does not have a strong flavor, although it might pick up flavors from its surroundings.
• Oxygen: Also considered tasteless. While essential for life, it is not safe to taste pure gases like oxygen directly.

Being able to distinguish substances by taste helps in common life scenarios, such as cooking. However, one must remember to use taste tests only when it is safe to do so.