The question incomplete , the complete question is:
A student dissolves of 18.0 g urea in 200.0 mL of a solvent with a density of 0.95 g/mL . The student notices that the volume of the solvent does not change when the urea dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to significant digits.
Answer:
The molarity and molality of the student's solution is 1.50 Molar and 1.58 molal.
Explanation:
Moles of urea = 
Volume of the solution = 200.0 mL = 0.2 L (1 mL = 0.001 L)

Molarity of the urea solution ;

Mass of solvent = m
Volume of solvent = V = 200.0 mL
Density of the urea = d = 0.95 g/mL


(1 g = 0.001 kg)
Molality of the urea solution ;


The molarity and molality of the student's solution is 1.50 Molar and 1.58 molal.
Solution :
Molar mass of
is :
M = 6×12 + 6×1 g
M = 78 g
78 gram of
contains
molecules.
So, 89.5 gram of
contains :

Now, from the formula we can see that one molecule of
contains 2 hydrogen atom . So, number of hydrogen atom are :

Hence, this is the required solution.
The ability to do work or cause change is
Energy
Not sure good luck on finding someone too help you
Alkina metals all have the similar proteries