Answer: obey the law of conservation of mass.
Explanation:
The law of conservation of mass states that matter can not be created nor be destroyed but can be transformed from one form to another. Whenever one balance an equation, if the equation is not balance it means something has be destroyed or created, this we give an ideal that the equation is not balance or wrong.
Answer : The solubility of this gaseous solute will be, 
Explanation :
First we have to calculate the concentration of solute.

Now we have to calculate the Henry's law constant.
Using Henry's law :

where,
C = concentration of solute = 
p = partial pressure = 27.59 kPa
= Henry's law constant = ?
Now put all the given values in the above formula, we get:


Now we have to calculate the solubility of this gaseous solute when its pressure is 79.39 kPa.



Therefore, the solubility of this gaseous solute will be, 
Dmitri Mendeleev is the answer
I believe the best answer to that question wud be D. I cud b wrong
Answer:
(a) (i) All the elements of a group have similar chemical properties because they have same no. of valence electrons in their outermost shell. (ii) All the elements of a period have different chemical properties because they have different no. of valence electrons in their atoms.