calculate the molarity and normality of a solution containing 4.0 g NaOH in 500 cm3 solution?
see below.
0.1
To calculate the molarity and normality of a solution, we need to know the number of moles of the solute and the volume of the solution.
First, let's find the number of moles of NaOH. We can use the formula:
moles = mass / molar mass
The molar mass of NaOH is:
Na (22.99 g/mol) + O (16.00 g/mol) + H (1.01 g/mol) = 39.99 g/mol
So, the number of moles of NaOH is:
moles = 4.0 g / 39.99 g/mol
Next, we need to convert the volume of the solution from cm³ to liters. Since 1 liter is equal to 1000 cm³, the volume of the solution in liters is 500 cm³ / 1000 cm³/L = 0.5 L.
Now, we can calculate the molarity and normality.
Molarity is defined as the number of moles of solute per liter of solution.
Molarity (M) = moles of solute / volume of solution in liters
Molarity = moles of NaOH / volume of solution in liters
Molarity = (4.0 g / 39.99 g/mol) / 0.5 L
Now we can simplify this:
Molarity = 0.1 mol / 0.5 L
Finally, we get the molarity of the solution:
Molarity = 0.2 M
Normality is another term used to express concentration, particularly for acid/base reactions. It is defined as the number of equivalents of a solute per liter of solution.
For NaOH, since it is a strong base, its normality is equal to its molarity.
So, the normality of the solution is 0.2 N.