A single water molecule has a given mass of about 2.992 x 10^-23 g = 18.02 amu. Estimate the number of molecules of water in a sample of 4.595 g of water.
4.595g * 1mol/(2.992*10^-23)g = ___ mol
I think I would like this answer better if it were written as follows:
4.595g * 1molecule/(2.992*10^-23)g = ___ molecules
To calculate the number of water molecules in a sample, you need to use Avogadro's number and the molar mass of water.
Here's how you can do it step by step:
1. Determine the molar mass of water, which is the sum of the atomic masses of its constituent atoms. In this case, water consists of two hydrogen atoms (H) with an atomic mass of approximately 1.01 amu and one oxygen atom (O) with an atomic mass of about 16.00 amu.
Molar mass of water = (2 * atomic mass of hydrogen) + atomic mass of oxygen
= (2 * 1.01 amu) + 16.00 amu
= 18.02 amu
Note: The molar mass of water is given as 18.02 amu.
2. Convert the mass of the water sample given to moles of water. To do this, divide the mass by the molar mass.
Moles of water = mass of water sample / molar mass
= 4.595 g / 18.02 g/mol
Note: The molar mass of water is given as 18.02 g/mol.
3. Convert the moles of water to the number of molecules using Avogadro's number, which is approximately 6.022 x 10^23 molecules/mol.
Number of molecules = moles of water * Avogadro's number
= (4.595 g / 18.02 g/mol) * (6.022 x 10^23 molecules/mol)
Performing the calculations:
Number of molecules = (4.595 g / 18.02 g/mol) * (6.022 x 10^23 molecules/mol)
= 1.455 x 10^23 molecules
Therefore, there are approximately 1.455 x 10^23 water molecules in the given sample of 4.595 g of water.