Final answer:
To find the mass of 8.0 x 10^25 formula units of NaCl, first calculate the number of moles by dividing the number of units by Avogadro's number, and then multiply by the molar mass of NaCl to get 7759.52 grams.
Step-by-step explanation:
To calculate the mass of 8.0 x 1025 formula units of sodium chloride (NaCl), we first need to determine the formula mass of NaCl. The formula mass is found by adding the atomic masses of sodium (Na) and chlorine (Cl), which are 22.99 amu and 35.45 amu respectively, giving us a total of 58.44 amu for one formula unit of NaCl. Next, we convert the formula mass to molar mass by changing the units from amu to grams per mole, maintaining the same numerical value, so the molar mass of NaCl is also 58.44 g/mol. We can then use Avogadro's number which states that one mole of any substance contains 6.022 x 1023 formula units. This helps us to find the number of moles in 8.0 x 1025 formula units.
The calculation is as follows:
- Divide the number of formula units (8.0 x 1025) by Avogadro's number (6.022 x 1023) to get the number of moles of NaCl.
- Multiply the number of moles by the molar mass of NaCl to find the total mass.
Carrying out these calculations:
- Number of moles = 8.0 x 1025 formula units ÷ 6.022 x 1023 formula units/mol = 132.8 moles.
- Mass of NaCl = 132.8 moles x 58.44 g/mol = 7759.52 grams.
Therefore, the mass of 8.0 x 1025 formula units of NaCl is 7759.52 grams.