<u>Answer:</u> The sample of Carbon-14 isotope will take 2377.9 years to decay it to 25 %
<u>Explanation:</u>
The equation used to calculate rate constant from given half life for first order kinetics:

where,
= half life of the reaction = 5730 years
Putting values in above equation, we get:

Rate law expression for first order kinetics is given by the equation:
![k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt%7D%5Clog%5Cfrac%7B%5BA_o%5D%7D%7B%5BA%5D%7D)
where,
k = rate constant = 
t = time taken for decay process = ? yr
= initial amount of the sample = 100 grams
[A] = amount left after decay process = (100 - 25) = 75 grams
Putting values in above equation, we get:

Hence, the sample of Carbon-14 isotope will take 2377.9 years to decay it to 25 %
Answer:
The addition of sulfate ions shifts equilibrium to the left.
Explanation:
Hello!
In this case, according to the following ionization of strontium sulfate:

It is evidenced that when sodium sulfate is added, sulfate,
is actually added in to the solution, which causes the equilibrium to shift leftwards according to the Le Ch athelier's principle. Thus, the answer in this case would be:
The addition of sulfate ions shifts equilibrium to the left.
Best regards!
Answer: The standard state refers to 1 atm and
.
Explanation:
It is known that a chemical/substance can either be present in a solid, liquid or gaseous state.
So, when the phase of a substance like solid, liquid or gas is present at 1 atmosphere pressure and at a temperature of
then it known as standard state of substance.
Thus, we can conclude that standard state refers to 1 atm and
.