2. Atoms & Elements

How many moles of sodium atoms are present in 3.60 × 10^{26} sodium atoms?

How many grams of carbon-12 are present in 1 mole of carbon-12?

How many atoms are present in one mole of gold (Au)?

For which compound does 0.256 mol have a mass of 12.8 g? (Assume the compound is pure.)

How many OH⁻ ions are present in 3.00 mol of Ca(OH)₂?

How many atoms are present in 12 grams of carbon-12?

How many hydrogen atoms are present in 5 molecules of water (H_2O)?

Fill in the blank: A mole is defined as the number of carbon atoms in __________ g of pure C-12.

How many moles of silver atoms are present in 1.8 × 10^{20} atoms of silver?

One atom of gold weighs 3.27 × 10^{-13} ng. How many gold atoms are present in 1.0 g of gold?

How many moles are present in 2.5 g of N_2?

How many molecules of glycine are present in 1.0 mole of glycine?

How many carbon atoms are present in 5.50 g of C?

What is the mole ratio of hydrogen (H) to nitrogen (N) in the ammonia molecule (NH_3)?

Which of the following samples contains a total of 9.0 × 10^{23} atoms?