Question

How would you prepare 100 ml of 0.1% Triton-X-100 detergent solution from a 100% Triton-X-100 stock?

Answer 1

We need to apply dilution law, which is based on the mass conservation principle

initial mass = final mass

this apply for moles as weel ( if there is no reaction, which is the case )

mol of A initially = mol of A finally

or, for this case

moles of A in stock = moles of A in diluted solution

Recall that

mol of A = Molarity of A * Volume of A

then

moles of A in stock = moles of A in diluted solution

Molarity of A in stock * Volume of A in stock = Molarity of A in diluted solution* Volume of A in diluted solution

Now, substitute known data

V dilution solution = 100 mL

assume concentration is by mass/moles so Mdiluted solution = 0.1%

we know that Mstock = 100%

so

100%* Volume of A in stock = 0.1% * 100 mL

solve for "Volume of A in stock"

Volume of A in stock = 0.1/100 *100 mL = 0.1 mL

Note that

we need 0.1 mL of Stock solution, then add ionized water up to V = 100 mL

this will have 0.1% Triton-X-100 concentration with a total vol ume of V = 100 mL