A student intend to prepare 200ml of 0.3M NaCl solution . The mass in gram of NaCl needed to prepare solution is ?!
How many mols do you need? That's M x L = mols.
Then mols = grams/molar mass. You know mols and molar mass, solve for grams.
To determine the mass of NaCl needed to prepare a 0.3M solution, we need to know the molar mass of NaCl and the volume of the solution.
Molar mass of NaCl:
The molar mass of NaCl is calculated by adding up the atomic masses of sodium (Na) and chlorine (Cl) in the compound. The atomic mass of sodium is 22.990 g/mol, while the atomic mass of chlorine is 35.453 g/mol. Adding these values gives a molar mass of NaCl as 58.443 g/mol.
Volume of the solution:
The question states that you need to prepare 200 ml of the solution.
Now, we can use the formula for molarity to find the mass of NaCl:
Molarity (M) = moles (n) / volume (V).
Rearranging the formula, we have:
n = M x V,
where n is the number of moles.
Substituting the given values:
M = 0.3 M,
V = 200 ml = 0.2 L.
n = 0.3 M x 0.2 L = 0.06 moles (mol).
Now, we can calculate the mass of NaCl using the moles and molar mass:
Mass (m) = moles (n) x molar mass (M).
Substituting the values:
m = 0.06 mol x 58.443 g/mol ≈ 3.50658 g.
Therefore, approximately 3.51 grams of NaCl is needed to prepare a 0.3M solution with a volume of 200 ml.