Answer:
is the rate constant for this reaction.
It will take
to concentration to reach 12.5% of its original value.
Explanation:
A decomposition reaction follows first order kinetics:
Half life of the reaction = 
Rate constant of the reaction = k
For first order reaction, half life and rate constant are linked with an expression :


is the rate constant for this reaction.
Initial concentration of reactant =
= x
Final concentration of reactant after time t =
= 12.5% of x = 0.125x
The integrated law of first order reaction :
![[A]=[A_o]\times e^{-kt}](https://tex.z-dn.net/?f=%5BA%5D%3D%5BA_o%5D%5Ctimes%20e%5E%7B-kt%7D)

t = 1,734.31 years =
It will take
to concentration to reach 12.5% of its original value.
Answer:
Precise but not accurate.
Explanation:
We can tell the performance of the balance is precise, because the repeated measurements give values close to one another.
However, the performance of the balance is not accurate, as the mean value of the repeated measurements (195.587) is not close to the value considered as true (in this case the standard calibration mass with a certified value of 200.002 g).
3.16 X 10^-11 M is the [OH-] concentration when H3O+ = 1.40 *10^-4 M.
Explanation:
data given:
H30+= 1.40 X 10^-4 M\
Henderson Hasslebalch equation to calculate pH=
pH = -log10(H30+)
putting the values in the equation:
pH = -log 10(1.40 X 10^-4 M)
pH = 3.85
pH + pOH =14
pOH = 14 - 3.85
pOH = 10.15
The OH- concentration from the pOH by the equation:
pOH = -log10[OH-]
10.5= -log10[OH-]
[OH-] = 10^-10.5
[OH-] = 3.16 X 10^-11 is the concentration of OH ions when hydronium ion concentration is 1.40 *10^-4 M.
Observation of experiment and intervention in newton's optics. newton followed the principle of light through prisms and the rays transmitted through them as a part of his observation. Various properties of light and its characteristics were exposed.
Explanation:
- Newton's investigation of light was based on prisms, lenses and optical rays.
- He stated that lights differing in colour also differed in degrees of re-frangibility.
- To support his theories newton employed "Proof by experiments" method. Each method was designated in revealing a specific property of light.
- A phenomenon known as Newton rings were discovered by newton.
- Newton recognized after pressing together two prisms that there was a transparent spot.