Be sure to answer all parts. The thermal decomposition of phosphine (PH3) into phosphorus and molecular hydrogen is a first-order reaction: 4PH3(g) → P4(g) + 6H2(g) The half-life of the reaction is 35.0 s at 680°C.

The given question is incomplete. The complete question is :

The thermal decomposition of phosphine (PH3) into phosphorus and molecular hydrogen is a first-order reaction: The half-life of the reaction is 35.0 s at 680°C. Calculate the first order rate constant.

a) The first order rate constant is

b) The time after which 95% reactions gets completed is 151 seconds

Explanation:

Expression for rate law for first order kinetics is given by:

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process  

a) for finding the rate constant

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

The first order rate constant is

b) for completion of 95 % of reaction

The time after which 95% reactions gets completed is 151 seconds

answers: to make sure that all of the broken pieces of tablet were added to the water, to allow for fair comparison of all three trials, with different particle sizes to avoid experimental error

the ratio of the conjugate base to the acid required to attain the desired ph.