<u>Answer:</u> The sample of Carbon-14 isotope is 37056.3 years old
<u>Explanation:</u>
The equation used to calculate rate constant from given half life for first order kinetics:

where,
= half life of the reaction = 5720 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 - 88.5) = 11.5 grams
Putting values in above equation, we get:

Hence, the sample of Carbon-14 isotope is 37056.3 years old
Answer:
B) exothermic.
Explanation:
Hello!
In this case, we need to keep in mind that exothermic reactions release heat, so they increase the temperature as the final energy is less than the initial energy; in contrast, endothermic reactions absorb heat, so they decrease the temperature as the final energy is greater than the initial energy.
In such a way, when a dissolution process shows off a negative enthalpy of dissolution, we infer it is an exothermic process due to the aforementioned; therefore, the answer is:
B) exothermic
.
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The sign of ΔSsys for a solid explosive converts to a gas is positive.
The term used for the measurement of randomness and disorderliness in a system is known as Entropy (S). ΔS calculates the change in entropy and it is positive when entropy increase and negative when entropy decreases.
Entropy increases when heat is added to the system. Addition of heat increases the randomness of the molecules and hence the entropy increases.
When a solid explosive converts to a gas the randomness increases. Explosive causes heat and the solid is converted into gas. The randomness of molecules is maximum in gases thus the entropy increases. The sign of ΔS is positive for this process.
If you need to learn more about the signs of ΔSsys, click here
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Answer: Please find answer in explanation column
Explanation:
During radioactive decay, the __unstable ________ isotope decays into a _stable ___________ isotope that has a different ____proton _______________ number
Or
During radioactive decay, the _ unstable parent nuclide ________ isotope decays into a _stable daughter nuclide ___________ isotope that has a different ____proton _______________ number.
There are 3 types of radioactive decay;alpha, beta and gamma, Of which the above clearly explains the beta decay. In beta decay, the unstable isotope having excess neutrons will undergo a beta decay emitting a beta particle.( ⁰₋₁e) causing the nucleus to loose a neutron but gain a proton.
Some heavy unstable isotopes which undergo radioactive (beta decay ) to become stable isotopes are phosphorus-32, strontium-90, iodine-131
Using Strontium 90 as an example , we have
⁹⁰₃₈St ----->⁹⁰₃₉Y + ⁰₋₁e
Strontium an unstable isotope undergoes a beta radioactive decay to form Yttrium.