# Chemistry: Gas Laws - Pressure in Bottle of Air & Liquid Helium

• Aggie
In summary, we need to find the pressure inside a 1.00-L metal bottle that initially contains air at 118K and 1.0 atm pressure, after injecting 120.0 mL of liquid helium and allowing the system to warm to room temperature (25 °C). To solve this, we need to convert the volume of the container from liters to cubic meters and calculate the number of moles of helium based on its density and injected volume. Using this information, we can use the ideal gas law to find the final pressure inside the bottle.

#### Aggie

Liquid helium at 4.2 K has a density of 0.147 g/mL. Suppose that a 1.00-L metal bottle that contains air at 118K and 1.0 atm pressure is sealed off. If we inject 120.0 mL of liquid helium and allow the entire system to warm to room temperature (25 °C), what is the pressure inside the bottle?

you need to show some work for us to help you. What have you tried doing/what equations do you have?

To approach this question you need to know the following:
The volume of the container. Convert l into m^3.
The number of moles of He. Consider the density and the volume of the liquid helium.

## 1. What are gas laws and how do they relate to pressure in a bottle of air and liquid helium?

Gas laws are a set of principles that describe the behavior of gases under various conditions, including pressure, temperature, and volume. These laws help us understand how gases behave in different environments, such as inside a bottle of air or liquid helium. The pressure inside a bottle of air or liquid helium is affected by the gas laws, specifically Boyle's law and Charles's law.

## 2. Why is pressure important in understanding the properties of gases?

Pressure is a key factor in understanding the behavior of gases because it determines how the gas will interact with its surroundings. In a bottle of air or liquid helium, the pressure is what keeps the gas molecules contained and determines how much space they take up. Changes in pressure can also affect the temperature and volume of a gas, which are important properties to consider in gas laws.

## 3. How is pressure measured in a bottle of air or liquid helium?

Pressure in a bottle of air or liquid helium is typically measured in units of atmospheres (atm), kilopascals (kPa), or pounds per square inch (psi). These units represent the amount of force exerted by the gas molecules on the walls of the container. Pressure can also be measured using specialized instruments such as a barometer or manometer.

## 4. How does pressure change as the temperature or volume of a gas changes in a bottle of air or liquid helium?

According to Boyle's law, pressure and volume have an inverse relationship, meaning that as one increases, the other decreases, and vice versa. This means that as the volume of a gas in a bottle of air or liquid helium increases, the pressure decreases, and vice versa. Similarly, according to Charles's law, pressure and temperature have a direct relationship, meaning that as one increases, the other also increases, and vice versa.

## 5. How does the pressure in a bottle of air or liquid helium change when the amount of gas inside changes?

In a bottle of air or liquid helium, the pressure is directly proportional to the number of gas molecules present. This means that as the amount of gas inside the bottle increases, so does the pressure, and vice versa. This is because more gas molecules will exert more force on the walls of the container, resulting in a higher pressure. This relationship is described by the ideal gas law, which combines the effects of pressure, volume, temperature, and amount of gas in a single equation.