Describe the preparation of 500 ml of 0.25 M solution of NaOH from NaOH pellets (88% purity).
molarity=mass/(molemass*volume)
mass=.25*40*.5
but that would be mass of pure NaOH.
massimpure=masspure/.88
so take that amount of pellets, add water to the 500ml mark while stirring, label and store.
Safety: wear goggles and gloves.
To prepare a 500 ml solution of 0.25 M NaOH from NaOH pellets with 88% purity, you would need to follow these steps:
Step 1: Calculate the required amount of NaOH:
Start by determining the molecular weight of NaOH, which is the sum of the atomic weights of sodium (Na), oxygen (O), and hydrogen (H). Na: 22.99 g/mol, O: 16 g/mol, H: 1.01 g/mol.
NaOH = 22.99 g/mol + 16 g/mol + 1.01 g/mol = 39.99 g/mol
To prepare a 0.25 M solution, you need 0.25 moles of NaOH per liter. Since you want to prepare 0.5 liters (500 ml), you would need:
0.25 moles/L * 0.5 L = 0.125 moles of NaOH
Since the NaOH pellets have an 88% purity, you need to account for the impurities. Divide the calculated amount by the purity to determine the required amount of NaOH:
0.125 moles / 0.88 = 0.142 moles
Now, multiply the number of moles by the molecular weight of NaOH to obtain the mass in grams:
0.142 moles * 39.99 g/mol = 5.67818 g
Step 2: Dissolve NaOH pellets in water:
Weigh out 5.67818 grams of NaOH pellets using an analytical balance.
Add about 400 ml of distilled water to a clean container. It is essential to use distilled water to ensure accurate measurements and to avoid introducing additional impurities.
Slowly pour the NaOH pellets into the water while stirring continuously. Stir until all the pellets have dissolved completely.
Step 3: Adjust to the final volume:
Continue stirring while adding more distilled water until the total volume reaches 500 ml. This step ensures that you have an accurate final volume.
Step 4: Mix thoroughly and store:
Thoroughly mix the solution to ensure a homogenous mixture.
Label the container with the solution's concentration (0.25 M NaOH), date, and any other relevant information.
Store the solution in a tightly sealed container, away from direct sunlight or heat sources.
Remember to follow proper safety precautions when handling chemicals and always wear appropriate protective gear.
And that's it! You have successfully prepared a 500 ml solution of 0.25 M NaOH from NaOH pellets with 88% purity.
To prepare a 0.25 M solution of NaOH from NaOH pellets with 88% purity, you would need to follow a step-by-step process. Here's how you can go about it:
Step 1: Calculate the molar mass of NaOH
The molar mass of NaOH can be calculated by adding the atomic masses of sodium (Na), oxygen (O), and hydrogen (H). The atomic masses are approximately Na = 23 g/mol, O = 16 g/mol, and H = 1 g/mol. Thus, the molar mass of NaOH is 23 + 16 + 1 = 40 g/mol.
Step 2: Determine the amount of NaOH required
To calculate the amount of NaOH required for preparing a 0.25 M solution, you need to use the formula:
Molarity (M) = Moles (mol) / Volume (L)
In this case, you want to make a 500 ml (0.5 L) solution with a concentration of 0.25 M. Rearranging the formula, you get:
Moles (mol) = Molarity (M) × Volume (L)
Substituting the given values, you have:
Moles (mol) = 0.25 M × 0.5 L = 0.125 mol
Step 3: Adjust for the purity of NaOH pellets
Since the NaOH pellets are 88% pure, you need to account for the impurities. Divide the calculated moles by the purity to obtain the actual number of moles of pure NaOH:
Actual Moles of NaOH = Moles (mol) / Purity
Substituting the numbers, you get:
Actual Moles of NaOH = 0.125 mol / 0.88 = 0.142 mol
Step 4: Calculate the mass of NaOH required
Now, use the molar mass of NaOH to calculate the mass required. The formula to calculate mass is:
Mass (g) = Moles (mol) × Molar Mass (g/mol)
Substituting the numbers, you have:
Mass (g) = 0.142 mol × 40 g/mol = 5.68 g
So, you would need approximately 5.68 grams of NaOH pellets to prepare 500 ml of a 0.25 M NaOH solution.
Note: Use caution when handling NaOH as it is corrosive and can cause burns. Make sure to wear appropriate protective gear such as gloves and goggles.