How many grams of naoh are needed to prepare 500ml of 125M naoh?

Answer 1

I think you may have missed a decimal point somewhere.

125M of NaOH would be a solution of sodium hydroxide containing 125 moles per litre. One mole of a compound is the same number of grams as the molecular weight of the molecule. Sodium hydroxide has a molecular weight of 40 ( sodium 23, oxygen 16, and hydrogen 1), so a one molar solution would have forty grams of NaOH per litre.

500ml of a 1M solution would contain 20g.

500ml of a 125M solution would need 2 500g. 1L of a 125M solution would need 5 000g of sodium hydroxide in the litre. The maximum solubility for NaOH in water at 20 degrees is 1110g per litre, so if you tried to dissolve 5 000g in a litre you would be left with 3 890g undissolved.

A 1.25M solution would have 1.25 times 40g per litre, which is 50g per litre. 500ml of this solution would have half this amount of NaOH, or 25g.

Answer 2

To calculate the grams needed, first find the molarity of the solution, which is 125 moles/liter. Then convert the volume to liters (500ml = 0.5 liters) and multiply the molarity by the volume in liters to find the number of moles needed. Finally, multiply the moles by the molar mass of NaOH (40 g/mol) to find the grams needed. In this case, it would be 31.25 grams of NaOH.