A water molecule has a mass of 2.99 x 10^ -23 g. What is the number of molecules of water in 18.01 g of water?
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https://www.jiskha.com/questions/1844015/a-single-water-molecule-has-a-given-mass-of-about-2-992-x-10-23-g-18-02-amu-estimate
To find the number of water molecules in 18.01 g of water, we need to use the concept of moles and Avogadro's number.
First, we need to calculate the number of moles of water in 18.01 g. We can use the formula:
Moles = Mass / Molar Mass
The molar mass of water (H2O) can be calculated by adding up the atomic masses of its constituent elements, hydrogen (H) and oxygen (O):
Molar Mass of H2O = (2 * Atomic Mass of H) + Atomic Mass of O
The atomic mass of hydrogen (H) is approximately 1.01 g/mol, and the atomic mass of oxygen (O) is approximately 16.00 g/mol. Substituting these values, we get:
Molar Mass of H2O = (2 * 1.01 g/mol) + 16.00 g/mol
= 18.02 g/mol
Now, we can calculate the number of moles of water:
Moles = Mass / Molar Mass
= 18.01 g / 18.02 g/mol
≈ 1.000 mol
Finally, we can use Avogadro's number to find the number of molecules in one mole of water. Avogadro's number is approximately 6.022 x 10^23 molecules/mol.
Number of Molecules = Moles * Avogadro's Number
= 1.000 mol * 6.022 x 10^23 molecules/mol
≈ 6.022 x 10^23 molecules
Therefore, there are approximately 6.022 x 10^23 water molecules in 18.01 g of water.