Question

Calculate the mass of NaOH needed to make 250ml of 0.200 M aqueous solution?

Answer 1

2.00 g of `NaOH` are needed.

Explanation:

Use the formula `MV=mol es`, where `M` is molarity in mol/l and `V` is volume in liters.

First, convert 250 ml to liters by dividing by 1000.

`250 color(white)(l)ml-:1000=0.250` liters

Now plug the molarity and volume into the formula:

`(0.200)(0.250)=0.0500` `mol` `NaOH`

Finally, convert moles into mass. The molar mass of `NaOH` is 39.997 g/mol.

`(0.0500 color(white)(l) mol color(white)(l) NaOH)/1 times (39.997 color(white)(l) g color(white)(l) NaOH)/(1 color(white)(l) mol color(white)(l) NaOH)=2.00 color(white)(l) g color(white)(l) NaOH`