Answer: must have THE SAME number of atoms for each element
Explanation: Chemical equations must be balanced -- they must have the same number of atoms of each element on both sides of the equation. As a result, the mass of the reactants must be equal to the mass of the products of the reaction.
No. Of protons = mass no. - no. Of neutrons
No. Of protons = 67 - 37
= 30
No. Of electrons = 28
Zinc will have 30 protons and 28 electrons. So, it will have +2 charge
Symbol - Zn^+2
Blank 1: nothing (to keep 2 total nitrogen)
blank 2: 3 (to make 6 total hydrogen)
blank 3: 2 (to make 2 total nitrogen and 6 total hydrogen)
hope this helps!! :)
Answer: 2.4 ml
Solution :
Molar mass of 
= 17 g/mole
Given,: 28% w/w of solution means 28 g of ammonia in 100 g of solution.
Mass of solution = 100 g
Now we have to calculate the volume of solution.
Molarity : It is defined as the number of moles of solute present in one liter of solution.
where,
n = moles of solute 
= volume of solution in liter = 0.11 L
Now put all the given values in the formula of molarity, we get
Using molarity equation:
