An endothermic reaction occurs when water and ammonium nitrate are combined. Which of the following statements correctly
1 answer:
You might be interested in
<u>Answer:</u> The correct statement is low temperature only, because entropy decreases during freezing.
<u>Explanation:</u>
The relationship between Gibb's free energy, enthalpy, entropy and temperature is given by the equation:
Where,
= change in Gibb's free energy
= change in enthalpy
T = temperature
= change in entropy
It is given that freezing of methane is taking place, which means that entropy is decreasing and is becoming negative. It is also given that the reaction is an exothermic reaction, this means that the
is also negative.
For a reaction to be spontaneous, must be negative.
From above equations, it is visible that will be negative only when the temperature will be low.
Hence, the correct statement is low temperature only, because entropy decreases during freezing.
Answer:
The half-life of the radioactive isotope is 346 years.
Explanation:
The decay rate of the isotope is modelled after the following first-order linear ordinary differential equation:
Where:
- Current isotope mass, measured in kilograms.
- Time, measured in years.
- Time constant, measured in years.
The solution of this differential equation is:
Where is the initial mass of the isotope. It is known that radioactive isotope decays at a yearly rate of 0.2 % annually, then, the following relationship is obtained:
The time constant associated to the decay is:
Finally, the half-life of the isotope as a function of time constant is given by the expression described below:
If , the half-life of the isotope is:
The half-life of the radioactive isotope is 346 years.