Determine the mass in grams of 5.49 × 10²¹ atoms of arsenic. (The mass of one mole of arsenic is 74.92 g.)

0.67 g

Explanation:

We know that 1 mole of an element is 6.02 x 10^(23) atoms

Now, arsenic has 5.49 × 10²¹ atoms

Thus;

Number of moles of arsenic = 5.49 × 10²¹ × 1/6.02 x 10^(23) = 9 × 10^(-3) moles

We are told that;

one mole of arsenic = 74.92 g.

Thus, 9 × 10^(-3) moles = 9 × 10^(-3) × 74.92/1 = 0.67428 g ≈ 0.67 g

the product of the pressure and volume is also constant