Calculate the molar concentration of a solution made by dissolving 20.0g of sodium hydroxide to make 300ml of solution.
mols NaOH = grams/molar mass = ?
M = mols/L solution = ?mols/0.300 = ?
To calculate the molar concentration of a solution, we need to know the molar mass of the solute and the volume of the solution.
Step 1: Calculate the number of moles of sodium hydroxide:
To do this, we divide the given mass of sodium hydroxide by its molar mass. The molar mass of NaOH is 22.99 g/mol for sodium, 16.00 g/mol for oxygen, and 1.01 g/mol for hydrogen. Adding them up gives us a molar mass of 39.99 g/mol.
Number of moles of NaOH = 20.0 g / 39.99 g/mol = 0.5 mol
Step 2: Calculate the volume of the solution in liters:
Given that the volume is 300 mL, we need to convert it to liters by dividing by 1000.
Volume of solution = 300 mL / 1000 mL/L = 0.3 L
Step 3: Calculate the molar concentration:
The molar concentration is the ratio of moles of solute to the volume of the solution in liters.
Molar concentration = Number of moles / Volume of solution
Molar concentration = 0.5 mol / 0.3 L = 1.67 mol/L
Therefore, the molar concentration of the solution is 1.67 mol/L.
To find the molar concentration of a solution, we need to determine the number of moles of the solute (in this case, sodium hydroxide) and divide it by the volume of the solution in liters.
Step 1: Convert the mass of sodium hydroxide from grams to moles.
The molar mass of sodium hydroxide (NaOH) can be calculated by adding the atomic masses of sodium (Na), oxygen (O), and hydrogen (H). The atomic masses are as follows:
Na = 22.99 g/mol
O = 16.00 g/mol
H = 1.01 g/mol
Now, calculate the molar mass of NaOH:
(22.99 g/mol) + (16.00 g/mol) + (1.01 g/mol) = 40.00 g/mol
So, the molar mass of NaOH is 40.00 g/mol.
To convert grams to moles, use the formula:
moles = mass/molar mass
Substitute the values into the formula:
moles = 20.0 g / 40.00 g/mol
moles = 0.5 mol
Step 2: Convert the volume of the solution from milliliters to liters.
The volume of the solution is given as 300 mL. To convert this to liters, divide by 1000 since there are 1000 mL in 1 L.
300 mL / 1000 mL/L = 0.3 L
Step 3: Calculate the molar concentration.
Molar concentration (C) is defined as moles/liters. Therefore, to calculate the molar concentration:
C = moles/volume
Substitute the values into the formula:
C = 0.5 mol / 0.3 L
C ≈1.67 mol/L
So, the molar concentration of the sodium hydroxide solution is approximately 1.67 mol/L.