Answer:
The nuclear decay of radioactive elements is a process that is a useful tool for determining the absolute age of fossils and rocks. It is used as a clock, in which daughter elements or isotopes converted from parent isotopes by decaying at a particular time.
Radioactive decay rates are constant and do not change over time. It is measured in half-life. A half-life is a time it takes half of a parent isotope to decay and converted into a stable daughter isotope. How many parent isotopes and daughter isotopes present in the fossil or their abundance can help in determining the age of fossil or rock.
The answears are in the attached photo.
Answer:
Buffer B has the highest buffer capacity.
Buffer C has the lowest buffer capacity.
Explanation:
An effective weak acid-conjugate base buffer should have pH equal to 
of the weak acid. For buffers with the same pH, higher the concentrations of the components in a buffer, higher will the buffer capacity.
Acetic acid is a weak acid and 
is the conjugate base So, all the given buffers are weak acid-conjugate base buffers. The pH of these buffers are expressed as (Henderson-Hasselbalch):
![pH=pK_{a}(CH_{3}COOH)+log\frac{[CH_{3}COO^{-}]}{[CH_{3}COOH]}](https://tex.z-dn.net/?f=pH%3DpK_%7Ba%7D%28CH_%7B3%7DCOOH%29%2Blog%5Cfrac%7B%5BCH_%7B3%7DCOO%5E%7B-%7D%5D%7D%7B%5BCH_%7B3%7DCOOH%5D%7D)
Buffer A: 
Buffer B: 
Buffer C: 
So, both buffer A and buffer B has same pH value which is also equal to . Buffer B has higher concentrations of the components as compared to buffer A, Hence, buffer B has the highest buffer capacity.
The pH of buffer C is far away from . Therefore, buffer C has the lowest buffer capacity.
Answer:
0.208mole of CO2
Explanation:
First, let us calculate the number of mole of HC3H3O2 present.
Molarity of HC3H3O2 = 0.833 mol/L
Volume = 25 mL = 25/100 = 0.25L
Mole =?
Mole = Molarity x Volume
Mole = 0.833 x 0.25
Mole of HC3H3O2 = 0.208mole
Now, we can easily find the number of mole of CO2 produce by doing the following:
NaHCO3 + HC2H3O2 → NaC2H3O2 + H2O + CO2
From the equation,
1mole of HC2H3O2 produced 1 mole of CO2.
Therefore, 0.208mole of HC2H3O2 will also produce 0.208mole of CO2
