How many molecular does 36.0 grams of water represent?
How many molecules does 36.0 grams of water represent?
There are 6.02E23 molecules in 18 g H2O (1 mol). 36 grams is 2 mols.
To determine the number of molecules in a given amount of a substance, you need to use Avogadro's number and the molar mass of the substance.
First, you need to determine the molar mass of water (H₂O). The molar mass of an element is the mass of one mole of that element, expressed in grams per mole. The molar mass of hydrogen (H) is approximately 1.01 g/mol, and the molar mass of oxygen (O) is approximately 16.00 g/mol. Since water has two hydrogen atoms and one oxygen atom, the molar mass of water is calculated as follows:
Molar mass of water (H₂O) = (2 × molar mass of hydrogen) + (1 × molar mass of oxygen)
= (2 × 1.01 g/mol) + (1 × 16.00 g/mol)
= 2.02 g/mol + 16.00 g/mol
= 18.02 g/mol
Next, you need to calculate the number of moles of water in 36.0 grams. To do this, divide the given mass (36.0 g) by the molar mass of water (18.02 g/mol):
Number of moles = Mass (g) / Molar mass (g/mol)
= 36.0 g / 18.02 g/mol
≈ 1.998 mol (rounded to 3 decimal places)
Finally, you can use Avogadro's number to find the number of molecules. Avogadro's number is approximately 6.022 × 10^23 molecules per mole. Multiply the number of moles by Avogadro's number:
Number of molecules = Number of moles × Avogadro's number
= 1.998 mol × (6.022 × 10^23 molecules/mol)
≈ 1.202 × 10^24 molecules
Therefore, 36.0 grams of water represents approximately 1.202 × 10^24 water molecules.