Final answer:
None of the provided options match the calculated number. To find the number of molecules in 8.26 kg of water, we convert the mass to grams, find the moles, and then use Avogadro's number to find that there are approximately 2.76 x 10^26 molecules of water.
Step-by-step explanation:
To determine how many molecules are present in 8.26 kg of water, we need to use Avogadro's number and the molar mass of water. Water has a molecular mass of 18 g/mol, and one mole of any substance contains 6.022 x 1023 molecules (Avogadro's number).
First, we convert the mass of water from kilograms to grams (8.26 kg x 1000 g/kg = 8260 g). Then, we divide this by the molar mass of water to find the number of moles:
8260 g / 18 g/mol = 459 moles of water
We then multiply the number of moles by Avogadro's number to find the number of molecules:
459 moles x 6.022 x 1023 molecules/mole = 2.76 x 1026 molecules
Therefore, none of the options (a) 4.61 x 1024 molecules, (b) 2.31 x 1024 molecules, (c) 1.15 x 1025 molecules, or (d) 5.75 x 1025 molecules match the calculated number. The correct number of molecules in 8.26 kg of water is approximately 2.76 x 1026.