prepare 500ml of a 1.25mol/l solution of sodium hydroxide
You need how many mols? That's M x L = 1.25 M x 0.500 = ?
Weigh that much solid NaOH, transfer quantitatively to a 500 mL volumetric flask, add some distilled water, swirl to dissolve all of the solid, cool (it will get hot), add enough distilled water to make to the mark on the volumetric flask, stopper, mix thoroughly, label. done.
To prepare 500ml of a 1.25mol/L solution of sodium hydroxide, you will need to follow these steps:
Step 1: Determine the amount of sodium hydroxide (NaOH) needed.
First, calculate the number of moles of NaOH required using the formula:
moles = concentration (mol/L) x volume (L)
moles = 1.25 mol/L x 0.5 L
moles = 0.625 mol
Step 2: Calculate the mass of sodium hydroxide.
Next, find the molar mass of NaOH, which is the sum of the atomic masses of its elements: Na (22.99 g/mol) + O (16.00 g/mol) + H (1.01 g/mol) = 39.99 g/mol.
To calculate the mass of NaOH needed, use the formula:
mass = moles x molar mass
mass = 0.625 mol x 39.99 g/mol
mass = 24.994375 g (rounding to 25.0 g)
Step 3: Dissolve sodium hydroxide in water.
Transfer 25.0 g of sodium hydroxide (NaOH) to a container. Then, add approximately 400 ml of water to the container. Stir the mixture until all the NaOH is dissolved. Finally, add more water until the total volume reaches 500 ml.
After following these steps, you will have successfully prepared 500ml of a 1.25mol/L solution of sodium hydroxide.
To prepare a 500 mL solution of sodium hydroxide with a concentration of 1.25 mol/L, you will need to follow these steps:
Step 1: Calculate the amount of sodium hydroxide required:
To determine the amount of sodium hydroxide needed, we can use the formula:
amount (in moles) = concentration (in mol/L) x volume (in L)
Given:
Concentration = 1.25 mol/L
Volume = 500 mL (convert to liters by dividing by 1000)
amount (in moles) = 1.25 mol/L x 500 mL / 1000 mL/L
Step 2: Calculate the mass of sodium hydroxide required:
Now that we know the amount of sodium hydroxide in moles, we can calculate its mass using its molar mass.
The molar mass of sodium hydroxide (NaOH) is:
Sodium (Na) = 22.99 g/mol
Oxygen (O) = 16.00 g/mol
Hydrogen (H) = 1.01 g/mol
Molar mass of NaOH = Na + O + H
= 22.99 g/mol + 16.00 g/mol + 1.01 g/mol
Finally, multiply the amount of sodium hydroxide in moles by the molar mass to obtain the mass:
mass of NaOH (in grams) = amount (in moles) x molar mass (in g/mol)
Step 3: Prepare the solution:
To prepare the solution, dissolve the calculated mass of sodium hydroxide in approximately 500 mL of water. Start by adding a smaller amount of water to the sodium hydroxide (as it can generate heat), and then gradually add more water while stirring until the solution is completely dissolved.
It is important to wear appropriate protective equipment like gloves and safety goggles while handling sodium hydroxide. Also, be cautious as sodium hydroxide solutions are highly caustic and can cause burns.
Remember to handle chemicals safely and dispose of them properly after use.