They have the same amount of valence electrons
Fractional distillation<span> is essentially the same as </span>simple distillation<span>except that a fractionating column is placed between the boiling flask and the condenser. The fractionating column is usually filled with glass or plastic beads. These beads improve the separation between the liquids being </span>distilled<span>.</span>
This hypothesis can be further substantiated by having different concentrations of acid and the same mass of limestone.
<h3>Rate of reaction</h3>
Though the question is incomplete, we must try to answer it the much we can. Recall that a hypothesis is a tentative explanation for an observation which is subject to empirical verification.
We know that the rate of reaction depends on the concentration of the acid. This hypothesis can be further substantiated by having different concentrations of acid and the same mass of limestone.
Learn more about rate of reaction: brainly.com/question/8592296
18. c
19. A
20. decomposition reaction
21. 4
22. 0.04%
Answer:
Mass of original sample = 100 g
Explanation:
Half life of cesium-137 = 30.17 years
Where, k is rate constant
So,
The rate constant, k = 0.02297 year⁻¹
Time = 90.6 years
Using integrated rate law for first order kinetics as:
![[A_t]=[A_0]e^{-kt}](https://tex.z-dn.net/?f=%5BA_t%5D%3D%5BA_0%5De%5E%7B-kt%7D)
Where,
![[A_t]](https://tex.z-dn.net/?f=%5BA_t%5D)
is the concentration at time t
![[A_0]](https://tex.z-dn.net/?f=%5BA_0%5D)
is the initial concentration
Initial concentration = ?
Final concentration = 12.5 grams
Applying in the above equation, we get that:-
![12.5\ g=[A_0]e^{-0.02297\times 90.6}](https://tex.z-dn.net/?f=12.5%5C%20g%3D%5BA_0%5De%5E%7B-0.02297%5Ctimes%2090.6%7D)
![[A_0]=\frac{12.5}{e^{-0.02297\times 90.6}}\ g=100\ g](https://tex.z-dn.net/?f=%5BA_0%5D%3D%5Cfrac%7B12.5%7D%7Be%5E%7B-0.02297%5Ctimes%2090.6%7D%7D%5C%20g%3D100%5C%20g)
<u>Mass of original sample = 100 g</u>
