The question is incomplete,the complete question :
Calculate the molality of a 10.0% (by mass) aqueous solution of hydrochloric acid:
a) 0.274 m
b) 2.74 m
c) 3.05 m
d) 4.33 m
e) the density of the solution is needed to solve the problem
Answer:
The molality of a 10.0% (by mass) aqueous solution of hydrochloric acid is 3.05 mol/kg.
Explanation:
10.0% (by mass) aqueous solution of hydrochloric acid.
10 grams of HCl is present in 100 g of solution.
Mass of HCl = 10 g
Mass of solution = 100 g
Mass of solution = Mass of solute + Mass of water
Mass of water = 100 g - 10 g = 90 g
Moles of HCl = 
Mass of water in kilograms = 0.090 kg
Molality = 
The molality of a 10.0% (by mass) aqueous solution of hydrochloric acid is 3.05 mol/kg.
It would have 98 neutrons.
Explanation:
The formula for finding neutrons when given the atomic number and the mass is to do (mass - atomic number.) In this case, the mass is 156 and the atomic number is 58. So we subtract 156 - 58, which gives us 98. Therefore, it would have 98 neutrons.
Answer:
It does not matter where the sample of water came from or how it was prepared. Its composition, like that of every other compound, is fixed.
Air is a mixture of elements which are formed my atoms that forms molecules. Hope that helps!