A solution is prepared by dissolving \(25.0 \mathrm{~g}\) of sucrose in \(175.0 \mathrm{~g}\) of water. Characterize its concentration by the appropriate percent composition.

When we mix a substance with a solvent, we create a solution. The concentration of this solution is a key concept in chemistry, representing the abundance of the solute—the substance dissolved—in the solvent, which is the liquid in which the solute is dissolved. One of the common ways to express concentration is by using percent composition.

Percent composition is calculated by taking the mass of the solute (in this case, sucrose), dividing it by the total mass of the solution (sucrose plus water), and multiplying by 100 to get a percentage. This figure tells us how much of the solution's total mass is made up of the solute. In our example, the solution has a percent composition of 12.5% sucrose, indicating that 12.5 grams of every 100 grams of the solution is sucrose. It's a straightforward indication of how concentrated the sucrose is in the water.

Understanding concentration is essential not just in chemistry but also in various industries such as pharmaceuticals, where exact dosages are critical, and in culinary arts, where flavors depend on the concentration of ingredients.

The mass of the solute is simply the weight of the substance that is being dissolved in the solvent to form a solution. In our example, sucrose is the solute and its mass is 25.0 grams. This measurement is vital because it directly influences the solution's concentration.

In practice, determining the mass of the solute involves using a balance or scale. Precision is important because a small difference in mass can lead to a significant change in concentration, which can be crucial in fields like medicine and chemistry. The mass of the solute is also fundamental for calculating other properties of solutions, such as molality and molarity, which are other ways to express concentration.

To facilitate understanding and accuracy in experiments, it is helpful to use a consistent method of measuring mass and to always record the units used. This way, when you report that the sucrose mass is 25.0 grams, others can replicate your results with confidence.

The mass of the solvent is the weight of the liquid in which the solute is dissolved. In the given example, water acts as the solvent, and its mass is 175.0 grams. The solvent is typically present in a greater amount than the solute, as it is the medium that holds the solute particles.

It's crucial to note that the mass of the solvent does not remain constant when we mix it with other substances. For instance, dissolving salts in water can change the water's mass due to reactions that occur between the solute and solvent. However, for sucrose dissolved in water, as in our example, the change is negligible, so we consider the mass of the solvent to be the same as the mass of the added water.

The mass of the solvent is also an essential part of many formulae in chemistry used to calculate various properties of solutions, such as boiling point elevation or freezing point depression. Understanding how to measure and apply the mass of the solvent is foundational to mastering the concept of solutions in chemistry.