Question

State Avogadro's law.

Short answer

Avogadro's law states: equal volumes of gases, at the same temperature and pressure, contain equal numbers of moles.

Step-by-step solution

Understand Avogadro's Law in Terms of Moles

Avogadro's law states that "equal volumes of gases, at the same temperature and pressure, contain an equal number of moles." This implies that the volume of a gas is directly proportional to the number of moles when temperature and pressure are held constant.

Relate Volume and Moles

The relation between volume \(V\) and number of moles \(n\) can be expressed as: \(V \propto n\). Alternatively, it can be written as \(V = kn\), where \(k\) is a constant of proportionality when temperature and pressure are constant.

Summarize Avogadro's Law

Avogadro's law provides a simple yet powerful tool for understanding gas behavior, indicating that if the amount (moles) of the gas changes while pressure and temperature remain constant, the volume will change in direct proportion to the number of moles.

Key concepts

Gas Laws

Gas laws are fundamental principles that describe how gases behave under different conditions. They help us understand the relationship between pressure, volume, temperature, and the number of moles of a gas. Avogadro's law is a key piece of the puzzle here, forming a bridge with other gas laws like Boyle's Law and Charles's Law.

Gas laws are essential for predicting how gases will react when they are compressed, expanded, heated, or cooled. They are not only crucial in academic contexts but also have practical applications in industries where controlling gases is necessary.

Moles

Moles are a basic unit of measurement used in chemistry to express amounts of a chemical substance. This unit is crucial when dealing with gases, as it allows for a standardized way to discuss and calculate their quantities.

One mole contains Avogadro’s number of particles, which is approximately \(6.022 \times 10^{23}\). This immense number helps in scaling down reactions to understandable levels, facilitating calculations for chemical reactions and gas properties.

• In gases, understanding the amount in moles allows for predictions about their volume under constant temperature and pressure.
• Moles link directly with Avogadro's law, highlighting how equal volumes of gases contain the same number of moles under constant conditions.

Volume and Gas Relationship

One of the most important relationships in gas laws is the direct proportionality between the volume of a gas and its moles, encapsulated by Avogadro's Law. When the number of moles of a gas increases, and its temperature and pressure remain constant, its volume increases proportionally.

Mathematically, this relationship is expressed as \(V = kn\), where \(V\) is volume, \(n\) is the number of moles, and \(k\) is a constant. This equation tells us that doubling the moles of gas will double the volume if pressure and temperature remain unchanged.

• This relationship is practical for calculations related to gas expansion and contraction.
• It can be visualized when inflating a balloon: adding more gas (moles) increases its size (volume).

Temperature and Pressure Constants

In gas laws, holding temperature and pressure constant allows us to predict changes in the properties of gases with more accuracy. With Avogadro's law, this constancy is crucial to maintain a clear relationship between volume and moles.

Both temperature and pressure influence how gas molecules move. Constant temperature and pressure mean that energy and space within the gas remain unchanged, letting us solely focus on how changes in the number of moles affect the volume.

• This constancy simplifies the calculation and prediction of gas behavior.
• It highlights the isolation of one variable change – namely, volume in response to mole changes.