Question #336a1

2 Answers
Jul 31, 2017

5.018×1029 molecules of H2O

Explanation:

According to mole concept :

1 mole of H20 = 6.022×1023 molecules of water = 18 gram H20

So 18 grams of H2O = 6.022×1023 no. of molecules H2O

And

150 grams of H2O = 6.022×102318×150 molecules H2O

= 5.018×1029 molecules of H2O

Jul 31, 2017

5.0163261024

Explanation:

To calculate the number of molecules of a substance, we simply multiply the amount of moles by Avogadro's number, which is equal to 6.0221023

But how many moles are in 150g of H2O?

Moles = Grams of a substance / Atomic Mass Of A Substance

Moles = 150g / 18.015 (The atomic mass of two H is 2.016. The atomic mass of O is 15.999)

Moles = 8.33mol

Therefore there are 8.336.0221023 molecules. (5.0163261024)