Molality of the solution is defined as the number of moles of a substance dissolved divided by the mass of the solvent:
Molality = number of moles / solvent mass
From the concentration of 39% (by mass) of HCl in water, we construct the following reasoning:
in 100 g solution we have 39 g hydrochloric acid (HCl)
number of moles = mass / molecular weight
number of moles of HCl = 39 / 36.5 = 1.07 moles
solvent (water) mass = solution mass - hydrochloric acid mass
solvent (water) mass = 100 - 39 = 61 g
Now we can determine the molality:
molality = 1.07 moles / 61 g = 0.018
Given :
Volume , V = 500 mL .
Molarity , M = 0.5 M .
Molecular mass of NaCl is 
.
To Find :
How many grams of NaCl is required .
Solution :
Let , NaCl required is x gram .
Molarity is given by :
Hence , this is the required solution.
Answer:
It represents the <em>number of atoms</em> of that particular element present in the compound. In C₂H₄O₂ there are 2 Carbon atoms, 4 Hydrogen atoms and 2 Oxygen atoms.
Answer:
D
Explanation:
D is not necessary to follow lab safety in Laboratory
A solid will start to melt when it reaches its melting point. For example the melting point of Helium is -272° Celsius and the melting point of Carbon is 3500° Celsius . Helium has the lowest melting point and carbon has the highest melting point in the periodic table.
