# Gas Laws and Stoichiometry

• bluegirlbalance
Then use mole ratio to determine amount of magnesium needed.In summary, the conversation discusses using stoichiometry and the ideal gas law to determine the mass of magnesium needed to react with a 0.25 L container of oxygen gas at 80oC and 770 mmHg. The participants suggest using PV=nRT to calculate the amount of oxygen and then using mole ratio to determine the amount of magnesium needed. One participant has three possible solutions (.945 g, .418 g, and .124 g) but is unsure which one is correct. They also mention the importance of showing work in order for others to provide assistance.

#### bluegirlbalance

Magnesium burns in oxygen gas to produce magnesium oxide. What mass of magnesium will react with a 0.25 L container of oxygen gas at 80oC and 770 mmHg?

I need to use stoichiometry to set up the pronlem and PV=nRT to solve.

I have three possible solutions, but I don't know which one is the correct one. The solutions I have are .945 g, .418 g, and .124 g.

Have you done any work on this problem? If you show work we can help you through the problem. Do you have the equation of the reaction?

Use PV=nRT to calculate amount of oxygen.

## 1. What are the basic gas laws?

The basic gas laws include Boyle's law, Charles's law, Gay-Lussac's law, and the combined gas law. Boyle's law states that the volume of a gas is inversely proportional to its pressure at a constant temperature. Charles's law states that the volume of a gas is directly proportional to its temperature at a constant pressure. Gay-Lussac's law states that the pressure of a gas is directly proportional to its temperature at a constant volume. The combined gas law combines all three laws into one equation.

## 2. How do you calculate the molar mass of a gas?

The molar mass of a gas can be calculated using the ideal gas law, PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature. Rearranging this equation to solve for n gives n = PV/RT. Then, dividing the mass of the gas by the number of moles calculated gives the molar mass.

## 3. What is the difference between ideal and real gases?

Ideal gases follow the ideal gas law perfectly, meaning they have no volume, no intermolecular forces, and no attractive or repulsive forces. Real gases, on the other hand, deviate from the ideal gas law due to their actual volume and intermolecular forces. They also exhibit behavior such as liquefaction and condensation at high pressures and low temperatures, which ideal gases do not.

## 4. How does stoichiometry apply to gas reactions?

Stoichiometry is the study of the quantitative relationships between reactants and products in a chemical reaction. In gas reactions, stoichiometry is used to determine the amount of each gas involved in the reaction, as well as the products that will be formed. This is important in determining the efficiency and yield of a reaction.

## 5. What is the difference between partial pressure and total pressure?

Partial pressure is the pressure each gas in a mixture would exert if it were the only gas present in the container. It is calculated by multiplying the mole fraction of the gas by the total pressure of the mixture. Total pressure, on the other hand, is the sum of all the partial pressures in the mixture. In a mixture of gases, each gas contributes to the total pressure based on its individual partial pressure.