The natural abundance of calcium in the earth's crust is 3.4% by mass. How many calcium atoms are present in a 1.50 g sample of the earth's crust?

Question

Quizplus · Accepted Answer

First, calculate the mass of calcium in the sample: 1.50 g * 0.034 = 0.051 g of calcium. Then, convert the mass of calcium to moles: 0.051 g / 40.08 g/mol = 0.001272 moles. Finally, convert moles to atoms using Avogadro's number: 0.001272 moles * 6.022 × 10^23 atoms/mol = 7.7 × 10^20 atoms.

The Natural Abundance of Calcium in the Earth's Crust Is