20 g NaOH are dissolved in 1 L H2O. What is the N of the NaOH solution
Na is sodium,
# equivalents NaOH = grams/equivalent weight
(eq wt NaOH is 40 which is the same as the molar mass because it has 1 OH group)
N = equivalents/L solution = ?
To calculate the normality (N) of a solution, you need to know the molarity (M) and the number of equivalents (neq) of the solute. To find the number of equivalents, you must know the balancing coefficients from the balanced chemical equation.
In this case, NaOH is a strong base that dissociates completely in water, so the balanced chemical equation is:
NaOH -> Na+ + OH-
From the equation, we can see that one mole of NaOH yields one mole of hydroxide ions (OH-). Therefore, the number of equivalents (neq) of NaOH is equal to its molarity (M).
Given that the solution contains 20 grams of NaOH dissolved in 1 liter of water, we need to convert the mass of NaOH to moles and the volume of water to liters to determine the molarity.
First, calculate the molar mass of NaOH:
Na: 1 atom x 22.99 g/mol = 22.99 g/mol
O: 1 atom x 16.00 g/mol = 16.00 g/mol
H: 1 atom x 1.01 g/mol = 1.01 g/mol
Total molar mass of NaOH = 22.99 g/mol + 16.00 g/mol + 1.01 g/mol = 40.00 g/mol
Now, convert grams of NaOH to moles:
20 g NaOH x (1 mol NaOH / 40.00 g NaOH) = 0.50 mol NaOH
Next, convert the volume of water to liters:
1 L = 1 L
Finally, we can now determine the molarity (M) of the NaOH solution:
M = moles of solute / liters of solution = 0.50 mol NaOH / 1 L = 0.50 M
In this case, the molarity (M) of the NaOH solution is 0.50 M, which is also equal to the number of equivalents (neq) since one mole of NaOH produces one mole of OH-. Therefore, the normality (N) of the NaOH solution is also 0.50 N.