Explanation:
The given data is:
The half-life of gentamicin is 1.5 hrs.
The reaction follows first-order kinetics.
The initial concentration of the reactants is 8.4 x 10-5 M.
The concentration of reactant after 8 hrs can be calculated as shown below:
The formula of the half-life of the first-order reaction is:

Where k = rate constant
t1/2=half-life
So, the rate constant k value is:

The expression for the rate constant is :

Substitute the given values and the k value in this formula to get the concentration of the reactant after time 8 hrs is shown below:

Answer: The concentration of reactant remains after 8 hours is 2.09x10^-6M.
Answer:
True.
But it only changes in physical change.
How?
Explanation:
The chemical reaction produces a new substance with new and different physical and chemical properties. Matter is never destroyed or created in chemical reactions. The particles of one substance are rearranged to form a new substance.
In a physical change, a substance's physical properties may change.
A chemical change is a permanent change. A Physical change affects only physical properties i.e. shape, size, etc. ... Some examples of physical change are freezing of water, melting of wax, boiling of water, etc. A few examples of chemical change are digestion of food, burning of coal, rusting, etc.
Hope this helps!
initial volume of the argon sample = 5.93L according to Boyle's law
What is Boyle's law ?
Boyle's law, also known as Mariotte's law, is a relationship describing how a gas will compress and expand at a constant temperature. The pressure (p) of a given quantity of gas changes inversely with its volume (v) at constant temperature, according to this empirical connection, which was established by the physicist Robert Boyle in 1662. In equation form, this means that pv = k, a constant.
According to Boyle's law
P1/V1 = P2/V2
P1 = initial pressure
P2 = final pressure
V1 =initial volume
V2= final volume
V1 = P1*V2/P2
V1 = 2.32*18.3/7.16 = 5.93L
initial volume of the argon sample = 5.93L according to Boyle's law
To know about Boyle's law from the link
brainly.com/question/26040104
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