What is the molarity of a salt solution in which 117.0 grams of salt (NaCl) is dissolved in water to give 5.00 L of solution? Show all work including units.
moles NaCl = grams NaCl/molar mass NaCl
Solve for moles NaCl.
Then the definition of M is moles/L.
Substitute moles and L and solve for M.
To find the molarity of a solution, we need to know the number of moles of solute (in this case, salt) and the volume of the solution.
First, we need to calculate the number of moles of salt (NaCl) using its molar mass.
The molar mass of NaCl is 58.44 g/mol (sodium has a mass of 22.99 g/mol, and chlorine has a mass of 35.45 g/mol).
Number of moles of NaCl = Mass of NaCl / Molar mass of NaCl
= 117.0 g / 58.44 g/mol
= 2.0 mol
Next, we divide the number of moles of salt by the volume of the solution to get the molarity.
Molarity (M) = Number of moles of solute / Volume of solution
= 2.0 mol / 5.00 L
= 0.4 M
Therefore, the molarity of the salt solution is 0.4 M.