Question

Avogadro's number, calculated from the atomic weight of hydrogen, tells us how many atoms or molecules are in a mole. The resulting base for all calculations of moles and molarity (how many molecules are present when you weigh out a substance or measure from a stock solution) is the following:

1 g of hydrogen atoms = 6 × 1023 hydrogen atoms = 1 mole of hydrogen
Sulfur has a molecular weight of 32. How many moles and atoms are there in 120 grams of sulfur?
(a) 3.75 and 6 × 1023
(b) 32 and 6 × 1023
(c) 1.75 and 1.05 ×1024
(d) 3.75 and 2.25 × 1024

Answer 1

To find the number of moles and atoms in 120 grams of sulfur, we divide the mass by the molar mass of sulfur and multiply by Avogadro's number.

Step-by-step explanation:

To determine the number of moles and atoms in 120 grams of sulfur, we need to use the molar mass of sulfur. The molar mass of sulfur is 32 g/mol.

To find the number of moles, we divide the mass of sulfur by its molar mass: 120 g / 32 g/mol = 3.75 mol. To find the number of atoms, we multiply the number of moles by Avogadro's number (6.022 × 1023 atoms/mol): 3.75 mol x 6.022 × 1023 atoms/mol = 2.25675 × 1024 atoms. Therefore, the correct answer is (D) 3.75 mol and 2.25 × 1024 atoms.