Chemistry help

Question

calculate the number of moles of NaOCl in 4mL of bleach. The bleach is 5.25% (w/v; weight to volume) aqueous NaOCl solutio. 

Answer 1

5.25% w/v means:  5.25 gram per 100 ml.

You have 4 ml: (5.25/100) * 4 = 0.21 gram

Now from gram to mole, divide by then molar mass of NaOCl (=22.99 (Na) + 16.00 (O) + 35.45 (Cl) = 74.44 grams/mole

 

So: 0.21 grams/74.44 grams/mole = 0.0028 mole, or 2.8*10^-3 mole

 

good luck