Question

Consider the reaction 4PH3(g) → P4(g) + 6H₂(g). Suppose that, at a particular moment during the reaction, molecular hydrogen is being formed at a rate of 0.244 m/s. (a) At what rate is P4 changing? m/s (b) At what rate is PH3 changing?

Answer 1

The rate at which P4 is changing is 0.0407 m/s, and PH3 is changing at a rate of 0.976 m/s, which are calculated based on their stoichiometric ratios in the given reaction and the rate of H2 formation.

Step-by-step explanation:

The stoichiometric coefficients from the reaction 4PH3(g) → P4(g) + 6H2(g) indicate that for every 4 moles of PH3 consumed, 1 mole of P4 is produced, and 6 moles of H2 are formed. To answer the questions:

• Rate of P4 formation: If H2 is forming at a rate of 0.244 m/s, P4 forms at a rate of 0.244 m/s ÷ 6 = 0.0407 m/s, since the ratio of their formation rates is 1:6.
• Rate of PH3 consumption: Given the stoichiometric ratio is 4 PH3 to 6 H2, the rate at which PH3 is changing (consumed) is 4 ÷ 0.244 m/s = 0.976 m/s.

For the average rate of formation and instantaneous rate of formation, the principle is directly reflective of the reaction's stoichiometry and the given rates at specific moments to determine the required rate calculations.