Question 21 (2 points)
The molar mass of water is 18.0 grams/mol. How many molecules are in 72.0 grams of water?
If you are unsure how to convert grams to particles, please see the example problem linked HERE.
a
3.13 x 1025 molecules
b
1.51 x 1023 molecules
c
2.41 x 1024 molecules
d
7.80 x 1026 molecules
To find the number of molecules in 72.0 grams of water, follow these steps:
1. Determine the number of moles of water in 72.0 grams using the molar mass of water (18.0 g/mol):
72.0 grams / 18.0 g/mol = 4 moles
2. Use Avogadro's number (6.022 x 10^23 molecules/mol) to convert moles to molecules:
4 moles x 6.022 x 10^23 molecules/mol = 2.41 x 10^24 molecules
Therefore, the answer is c) 2.41 x 10^24 molecules.