Problem 26 - Chemistry The Molecular Science

Question

Calculate the volume of a \(23.4-\mathrm{g}\) sample of bromobenzene, density \(=1.49 \mathrm{~g} / \mathrm{mL}\).

Step-by-Step Solution

Answer

The volume is approximately 15.70 mL.

Step 1: Identify the Formula

To find the volume of a substance when the mass and density are known, we use the formula: \[\text{Volume} = \frac{\text{Mass}}{\text{Density}}\]

Step 2: Substitute the Known Values

Substitute the given values into the formula: the mass of the bromobenzene sample is 23.4 g, and the density is 1.49 g/mL. Thus, we have: \[\text{Volume} = \frac{23.4}{1.49}\]

Step 3: Calculate the Volume

Perform the division to calculate the volume:\[\text{Volume} = \frac{23.4}{1.49} \approx 15.70 \text{ mL}\]

Step 4: Provide the Final Answer

Based on the calculation, the volume of the 23.4 g bromobenzene sample is approximately 15.70 mL.

Key Concepts

Volume calculation

Calculating volume is important in chemistry when you know the mass and density of a material. Here, we use the simple formula: \[ \text{Volume} = \frac{\text{Mass}}{\text{Density}} \] to determine the space occupied by a substance.

• Understand the Formula: Volume is calculated by dividing the mass of a material, usually in grams, by its density, which tells us how much mass exists in a certain volume.
• Substitute Values: Plug the known values into the formula to find the volume. For example, with a mass of 23.4 grams and density of 1.49 g/mL, you perform the calculation \( \frac{23.4}{1.49} \), resulting in 15.70 mL.

Breaking down these steps shows the simplicity of the process, whether in a classroom or a professional lab. Always ensure the units used are compatible during calculations.

Bromobenzene

Bromobenzene is a colorless liquid commonly utilized in the synthesis of organic compounds. Understanding its properties is crucial when working with this chemical.

• Basics: Bromobenzene consists of a benzene ring with a bromine atom attached. This setup makes it a versatile compound in chemical reactions.
• Properties: At room temperature, it is a liquid, and it has a higher density than water, with a value of 1.49 g/mL as seen in our calculation. This indicates that it is heavier per unit volume compared to water.
• Uses: It is widely used in the preparation of other compounds, serving as an intermediate in pharmaceuticals, and as a building block for more complex molecules.

Knowing about bromobenzene helps us understand its role in various chemical processes and its handling in labs.

Mass and volume relationship

The relationship between mass, volume, and density is a foundational concept in chemistry. It helps in determining how much space a substance will occupy, how tightly packed the atoms are, and consequently, its behavior under different conditions.

• Mass: This is the amount of matter present in a substance, measured in grams (g).
• Volume: This is the space that the substance occupies, typically measured in milliliters (mL) or liters (L).
• Density: This is the ratio of mass to volume \( \left( \frac{\text{Mass}}{\text{Volume}} \right) \), often expressed in g/mL or g/cm³. Understanding density offers insights into how substances will respond to physical and chemical changes.

When mass and density are known, calculating volume becomes straightforward, as shown in our example, making it an essential tool in material science and chemistry.