Question

Roopa weighs 10g of water and 4g of NaOH. Calculate the total number of moles contained in a mixture.​ [Chemistry question]

Answer 1

At first we have to know the mass of a single mole of both water and NaOH or simply the molar mass of water and NaOH.

The molar mass of water is approximately 18.015 grams.

And the molar mass of NaOH is approximately 39.99 grams.

So,

18.015 grams of water = 1 mole

1 gram of water = 1/18.015 mole

10 gram= 10/18.015 = 0.555 mole.

And,

39.99 grams of NaOH = 1 mole

1 gram of NaOH = 1/39.99 mole

4 gram of NaOH = 4/39.99 mole = 0.1 mole

Total amount of mole in that mixture = (0.555+ 0.1 ) = 0.655 mole (answer)