Consider the reaction:
2 HBr (g) → H₂ (g) + Br₂ (g)
c. If the volume of the reaction vessel in part b was 1.25 L, what amount of Br₂ (in moles) was formed during the first 15.0 s of the reaction?

Verified step by step guidance

1. Determine the rate of formation of Br_2 from the given reaction. The rate of formation of Br_2 is equal to the rate of disappearance of HBr divided by 2, based on the stoichiometry of the reaction.
2. Use the rate of disappearance of HBr to find the rate of formation of Br_2. If the rate of disappearance of HBr is given or can be calculated, divide it by 2 to find the rate of formation of Br_2.
3. Calculate the amount of Br_2 formed using the rate of formation and the time period. Multiply the rate of formation of Br_2 by the time (15.0 s) to find the amount of Br_2 formed in moles.
4. Consider the volume of the reaction vessel. Since the volume is given as 1.25 L, ensure that the rate of formation is consistent with this volume, if necessary.
5. Verify the units and ensure that the final amount of Br_2 is expressed in moles, as required by the problem.

Key Concepts

Stoichiometry

Stoichiometry is the calculation of reactants and products in chemical reactions based on the balanced chemical equation. It allows us to determine the relationships between the quantities of substances involved in a reaction. In this case, the stoichiometric coefficients indicate that 2 moles of HBr produce 1 mole of Br2, which is essential for calculating the amount of Br2 formed.

Ideal Gas Law

The Ideal Gas Law relates the pressure, volume, temperature, and number of moles of a gas through the equation PV = nRT. This law is crucial for understanding how gases behave under different conditions. In this question, knowing the volume of the reaction vessel (1.25 L) allows us to calculate the number of moles of Br2 produced using the ideal gas law, assuming standard conditions.

Reaction Rate

Reaction rate refers to the speed at which reactants are converted into products in a chemical reaction. It can be influenced by factors such as concentration, temperature, and the presence of catalysts. In this scenario, understanding the time frame (15.0 s) is important for determining how much Br2 is formed during that period, which can be calculated using the reaction rate and stoichiometry.