Question

The decomposition of ammonia on a metal surface to form _______ and _______ is a zero-order reaction. At 873 °C, the value of the rate constant is _______ mol/L · s. How long will it take to completely decompose 1.0 g of _______ in a 1.0-L flask?

Answer 1

The decomposition of ammonia on a metal surface to form nitrogen and hydrogen is a zero-order reaction. The rate constant of the reaction at 873 °C is 2.10 × 10-6 mol/L/s. To completely decompose 1.0 g of ammonia in a 1.0-L flask, you will need to calculate the time it takes to decompose that amount using the rate expression and the given data.

Step-by-step explanation:

The decomposition of ammonia on a metal surface to form nitrogen and hydrogen is a zero-order reaction. In a zero-order reaction, the rate of the reaction is independent of the concentration of the reactant. The rate law for this reaction would be Rate = k, where k is the rate constant. To determine the rate constant, we can use the given data. At 873 °C, the rate is given as 2.10 × 10-6 mol/L/s. This means that at that temperature, the reaction is occurring at a rate of 2.10 × 10-6 mol of ammonia decomposed per liter of solution per second. To completely decompose 1.0 g of ammonia in a 1.0-L flask, we need to calculate the time it takes to decompose that amount. First, convert the mass of ammonia to moles using its molar mass. Then, use the rate expression Rate = k[NH3]⁰, where [NH3] is the initial concentration of ammonia. Rearrange the equation to solve for time: t = (1/[NH3]⁰) * (mass of ammonia/molarmass) / rate. Plug in the known values to calculate the time.