Question

The rate of decomposition of PH3 was studied at 891.00 °C. The rate constant was found to be 0.0605 s^-1. 4PH3 -------> P4 + 6H2If the reaction is begun with an initial PH3 concentration of 0.95 M, what will be the concentration of PH3 after 16.00 s? _______ M

Answer 1

The question provided the equation for the decomposition of PH3 and the rate of decomposition for this compound (0.0605 s^-1), and requires us to calculate the final concentration of PH3 after 16.00 s given that the reaction started with 0.95 M of this compound.

The following information was provided by the question:

- Balanced chemical equation:

`4PH_3\to P_4+6H_2`

- rate of decomposition of PH3 = 0.0605 1/s

- initial concentration of PH3 = 0.95 M

- time of reaction = 16.00 s

The rate of the reaction given can be written as:

`\text{rate = -}(\Delta\lbrack PH_3\rbrack)/(4\Delta t)=(\Delta\lbrack P_4\rbrack)/(\Delta t)=(\Delta\lbrack H_2\rbrack)/(6\Delta t)`

From the expression of rate above and knowing the rate of decomposition of PH3, we can calculate the Δ[PH3] and, using the initial concentration given, we can find the final concentration of PH3 after 16.00s.

First, let's calculate the Δ[PH3]: