<u>Answer:</u> The remaining sample of X is 6.9 grams.
<u>Explanation:</u>
All the radioactive reactions follow first order kinetics.
The equation used to calculate rate constant from given half life for first order kinetics:
![t_{1/2}=\frac{0.693}{k}](https://tex.z-dn.net/?f=t_%7B1%2F2%7D%3D%5Cfrac%7B0.693%7D%7Bk%7D)
We are given:
![t_{1/2}=4.7min](https://tex.z-dn.net/?f=t_%7B1%2F2%7D%3D4.7min)
Putting values in above equation, we get:
![k=\frac{0.693}{4.7min}=0.147min^{-1}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B0.693%7D%7B4.7min%7D%3D0.147min%5E%7B-1%7D)
The equation used to calculate time period follows:
![N=N_o\times e^{-k\times t}](https://tex.z-dn.net/?f=N%3DN_o%5Ctimes%20e%5E%7B-k%5Ctimes%20t%7D)
where,
= initial mass of sample X = 78 g
N = remaining mass of sample X = ? g
t = time = 16.5 min
k = rate constant = ![0.147min^{-1}](https://tex.z-dn.net/?f=0.147min%5E%7B-1%7D)
Putting values in above equation, we get:
![N=78\times e^{-(0.147min^{-1}\times 16.5min)}\\\\N=6.9g](https://tex.z-dn.net/?f=N%3D78%5Ctimes%20e%5E%7B-%280.147min%5E%7B-1%7D%5Ctimes%2016.5min%29%7D%5C%5C%5C%5CN%3D6.9g)
Hence, the remaining amount of sample X is 6.9 g
Answer:
<h3>Uniform polarization of the heart membranes</h3>
Explanation:
Conserved or conservation of energy .
<h3>
What is First law of thermodynamics.</h3>
The First Law of Thermodynamics states that heat is a form of energy, and thermodynamic processes are are related to conservation of energy.
It also stated that the conservation of energy principle to systems where heat transfer and doing work are the methods of transferring energy into and out of the system.
Mathematically, The first law of thermodynamics states that the change in internal energy of a system ΔU, equals the net heat transfer into the system Q, plus the net work done on the system W. In equation form, the first law of thermodynamics is,
ΔU=Q+W
Here ΔU is the change in internal energy U.
Qis the net heat transferred into the system
W is the net work done on the system.
Hence,
The first law of thermodynamics states that heat added to a system is neither created nor destroyed but is conserved as it changes into other forms of energy.
For more thermodynamic related question visit
brainly.com/question/1604031
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