Gen Chem 1 partial pressures and gas stoichiometry flashcards

What is Dalton's Law of Partial Pressures?

In a mixture of gases, the total pressure is the sum of the partial pressures of each gas. Formula: $\displaystyle P_{total} = P_1 + P_2 + P_3 + ...$

True or False: Partial pressure depends on the amount of gas present.

True. The partial pressure of a gas increases with an increase in the number of moles of that gas.

Calculate the partial pressure of O₂ in a mixture: 3 moles total, 1 mole O₂.

Using Dalton's Law: $\displaystyle P_{O_2} = \frac{n_{O_2}}{n_{total}} imes P_{total}$ If $\displaystyle P_{total} = 1 atm$: $\displaystyle P_{O_2} = \frac{1}{3} imes 1 atm = 0.33 atm$

What is the definition of partial pressure?

The pressure exerted by a single gas in a mixture of gases. It is a component of the total pressure.

Fill in the blank: Total pressure equals the ______ of partial pressures.

sum

Comparison: Total pressure vs. Partial pressure.

Total pressure: Exerted by the entire gas mixture. Partial pressure: Exerted by an individual gas.

How do you find the partial pressure of CO₂ in a mix?

Use the formula: $\displaystyle P_{CO_2} = \frac{n_{CO_2}}{n_{total}} imes P_{total}$ Fill in moles and total pressure.

What influences the partial pressure of a gas?

Factors include: - Amount of gas (moles) - Volume of container - Temperature

True or False: Partial pressure changes with temperature.

False. Partial pressure is independent of temperature if the amount of gas remains constant.

Calculate total pressure if P₁ = 0.5 atm, P₂ = 0.3 atm.

Using Dalton's Law: $\displaystyle P_{total} = P_1 + P_2 = 0.5 atm + 0.3 atm = 0.8 atm$

What is the mole fraction of a gas?

The ratio of the number of moles of that gas to the total number of moles in the mixture. Formula: $\displaystyle X_i = \frac{n_i}{n_{total}}$

Fill in the blank: The partial pressure of a gas is calculated using ______.

mole fraction and total pressure.

Why do gases exert pressure?

Gases exert pressure due to collisions of gas particles with the walls of the container.

What is the relationship between mole fraction and partial pressure?

Direct relationship: $\displaystyle P_i = X_i imes P_{total}$ where $\displaystyle X_i$ is the mole fraction.

True or False: All gases in a mixture behave independently.

True. Each gas in a mixture contributes to the total pressure without interaction with others.

Calculate the partial pressure of N₂ in a mix: 2 moles N₂, total 4 moles.

Using: $\displaystyle P_{N_2} = \frac{n_{N_2}}{n_{total}} imes P_{total}$ If $\displaystyle P_{total} = 1 atm$: $\displaystyle P_{N_2} = \frac{2}{4} imes 1 atm = 0.5 atm$

What is gas stoichiometry?

Gas stoichiometry involves using balanced chemical equations to calculate the relationships between moles, volumes, and conditions of gases in reactions.

Calculate the volume of gas produced.

From the reaction: 2 H₂ + O₂ → 2 H₂O. If 4 moles of H₂ react, 4 L H₂O is produced at STP.

True or False: All gases occupy the same volume at STP.

True. At STP (standard temperature and pressure), one mole of any ideal gas occupies 22.4 L.

Convert moles of gas to volume.

Use the ideal gas law: $\displaystyle PV = nRT$. For 1 mole at STP, V = 22.4 L.

What relationship does Avogadro's Law describe?

Avogadro's Law states that equal volumes of gases, at the same temperature and pressure, contain equal numbers of molecules.

How to find moles from volume?

Use the formula: $\displaystyle n = \frac{V}{22.4 ext{ L}}$ at STP. E.g., 44.8 L of gas = 2 moles.

What is the role of coefficients in gas reactions?

Coefficients in a balanced equation represent the volume ratios of gases involved in the reaction under identical conditions.

Cause → Effect: Increasing temperature of a gas?

Increases the volume if pressure is constant, according to Charles's Law.

Calculate moles from mass of gas.

Use the formula: $\displaystyle n = \frac{m}{M}$, where m = mass in grams and M = molar mass in g/mol.

What is Dalton's Law of Partial Pressures?

In a mixture of gases, the total pressure is the sum of the partial pressures of each gas.

Fill in the blank: At STP, 1 mole of gas = _____.

22.4 L.

True or False: Molar volume is constant regardless of gas type.

True. Molar volume is consistent at STP for all ideal gases.

How to find volume of gas in a reaction?

Use stoichiometry: $\displaystyle V_1 : V_2 = n_1 : n_2$, where volumes correspond to moles in a balanced equation.

Calculate total pressure in a mixture.

If 2 atm of O₂ and 3 atm of N₂, total pressure = 2 atm + 3 atm = 5 atm.