calculate the molarity and normality of a solution containing 4.0 g NaOH in 500 cm3 solution
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Number of moles of NaOH=4/40=0.1
Molarity of solution= 500 cm3=
5 litres
0.1/5=0.02M
Ans 0.02 M
To calculate the molarity and normality of a solution, you need to know the amount of solute in grams and the volume of the solution in liters.
First, let's convert the volume from cubic centimeters (cm3) to liters (L):
500 cm3 = 500/1000 = 0.5 L
Now, we can calculate the molarity (M) using the formula:
Molarity (M) = moles of solute / volume of solution (in liters)
To find the moles of NaOH, we need to use its molar mass. The molar mass of NaOH is:
Na = 22.99 g/mol
O = 16.00 g/mol
H = 1.01 g/mol
So, the molar mass of NaOH is:
22.99 + 16.00 + 1.01 = 40.00 g/mol
Now, let's calculate the moles of NaOH:
moles = mass / molar mass
moles = 4.0 g / 40.00 g/mol
moles = 0.10 mol
Finally, we can calculate the molarity:
Molarity (M) = 0.10 mol / 0.5 L
Molarity (M) = 0.20 M
Therefore, the molarity of the solution is 0.20 M.
To calculate the normality (N), we also need to consider the number of equivalents of the solute. In this case, NaOH is a monoprotic base, so the number of equivalents is the same as the number of moles.
Normality (N) = number of equivalents / volume of solution (in liters)
In this case, the normality would be equal to the molarity:
Normality (N) = 0.20 N
Therefore, the normality of the solution is also 0.20 N.