Calculate the molarity and molality of a solution containing 10.35gm of K2CO3 in 250cm3 of solution (density = 1gm cm-1)
Cavahahssjjdjd
Simple
To calculate the molarity (M) and molality (m) of a solution, we need to use the following formulas:
Molarity (M) = moles of solute / volume of solution in liters
Molality (m) = moles of solute / mass of solvent in kilograms
First, let's calculate the moles of K2CO3:
Molar mass of K2CO3 = (2 x atomic mass of K) + (1 x atomic mass of C) + (3 x atomic mass of O)
= (2 x 39.1 g/mol) + 12.01 g/mol + (3 x 16.00 g/mol)
= 78.2 g/mol + 12.01 g/mol + 48.00 g/mol
= 138.21 g/mol
Moles of K2CO3 = mass of K2CO3 / molar mass of K2CO3
= 10.35 g / 138.21 g/mol
≈ 0.0749 mol
Next, let's calculate the volume of the solution in liters:
Volume of solution = 250 cm^3 = 0.25 L
Now, we can calculate the molarity (M) and molality (m):
Molarity (M) = moles of solute / volume of solution in liters
= 0.0749 mol / 0.25 L
≈ 0.2996 M
Molality (m) = moles of solute / mass of solvent in kilograms
First, let's calculate the mass of the solvent:
Mass of solvent = volume of solution x density
= 0.25 L x 1 g/cm^3
= 0.25 kg
Now, we can calculate the molality:
Molality (m) = moles of solute / mass of solvent in kilograms
= 0.0749 mol / 0.25 kg
= 0.2996 m
Therefore, the molarity of the solution is approximately 0.2996 M and the molality is approximately 0.2996 m.
To calculate the molarity and molality of a solution, we need to first calculate the number of moles of the solute (K2CO3) and the mass of the solvent.
Step 1: Calculate the number of moles of K2CO3:
To find the number of moles, we use the formula:
moles = mass / molar mass
The molar mass of K2CO3 can be calculated by adding up the atomic masses of its constituent elements:
Molar mass of K2CO3 = (2 * atomic mass of K) + atomic mass of C + (3 * atomic mass of O)
Using the atomic masses:
Atomic mass of K = 39.10 g/mol
Atomic mass of C = 12.01 g/mol
Atomic mass of O = 16.00 g/mol
Molar mass of K2CO3 = (2 * 39.10) + 12.01 + (3 * 16.00)
Now, calculate the moles of K2CO3:
moles = 10.35 g / Molar mass of K2CO3
Step 2: Calculate the volume of the solution in liters:
To calculate the volume in liters, we need to convert the given volume from cm^3 to liters:
Volume = 250 cm^3 = 250 / 1000 = 0.25 L
Step 3: Calculate the molarity of the solution:
Molarity is defined as moles of solute divided by volume of solution in liters.
Molarity (M) = moles / volume (in liters)
Molarity = moles / 0.25 L
Step 4: Calculate the mass of the solvent:
The mass of the solvent can be calculated using the density of the solution. The formula for mass is:
Mass = Volume * Density
Mass of solvent = 0.25 L * 1 g/cm^3 = 0.25 kg
Step 5: Calculate the molality of the solution:
Molality is defined as moles of solute divided by mass of the solvent in kilograms.
Molality (m) = moles / mass of solvent (in kg)
Molality = moles / 0.25 kg
Now, you can substitute the values obtained in steps 1, 3, and 5 to find the molarity and molality of the solution.