For a first order reaction, the half life is inversely proportional to the rate constant.
The formula is
half life = ln(2)/k = 0.693/k
where k is the rate constant
t = 5.50 minutes
k = ln(2)/5.50 = 0.126 min^-1
Your rate constant is 0.126 min^-1.
Explanation:
Entropy means the amount of randomness present within the molecules of the body of a substance.
Relation between entropy and microstate is as follows.
S = 
where, S = entropy
= Boltzmann constant
= number of microstates
This equation only holds good when the system is neither losing or gaining energy. And, in the given situation we assume that the system is neither gaining or losing energy.
Also, let us assume that
= 1, and
= 0.833
Therefore, change in entropy will be calculated as follows.

= 
= 
= 
or, = 
Thus, we can conclude that the entropy change for a particle in the given system is
J/K particle.
Vinegar pH 3.2: Weak acid
Battery acid pH 0.5: Strong acid
Shampoo pH 7.0: Neutral
Ammonia pH 11.1 Strong base
The element has 83 electrons