Answer:
In 23.49 minutes the concentration of A to be 66.8% of the initial concentration.
Explanation:
The equation used to calculate the constant for first order kinetics:
.....(1)
Rate law expression for first order kinetics is given by the equation:
......(2)
where,
k = rate constant
=Half life of the reaction = 
t = time taken for decay process = ?
= initial amount of the reactant = 0.163 M
[A] = amount left after time t = 66.8% of ![[A_o]](https://tex.z-dn.net/?f=%5BA_o%5D)
[A]=


t = 1,409.19 s
1 minute = 60 sec

In 23.49 minutes the concentration of A to be 66.8% of the initial concentration.
Answer : Option A) the arrangement of bonded atoms.
Explanation : A structural formula of certain molecule depicts the way the atoms are arranged in that particular molecule in any polyatomic species. It helps in deciding the chemical properties of that polyatomic molecule.
Answer:
8 Silicon atom are present in unit cell.
16 oxygen atoms are present unit cell.
Explanation:
Number of atoms in unit cell = Z =?
Density of silica = tex]2.32 g/cm^3[/tex]
Edge length of cubic unit cell = a = 0.700 nm = 

Molar mass of Silica = 
Formula used :
where,
= density
Z = number of atom in unit cell
M = atomic mass
= Avogadro's number
a = edge length of unit cell
On substituting all the given values , we will get the value of 'a'.
1 silicon is 2 oxygen atoms. then 8 silicon atoms will be 16 oxygen atoms.