How many atoms of gold (Au) are present in a 90.2-g sample? The molar mass of gold is 197.0 g/mol.

How many moles of water are contained in 1.99 × 10^{26} molecules of water?

How many molecules are present in 25 grams of NH_3?

How many moles are present in 3.01 × 10^{23} molecules of H_2O?

Which statement best explains the purpose of using a mole in the measurement of matter?

How many moles are present in 2.5 g of N_2?

Which of the following best represents the number of particles in one mole of a substance?

How many molecules are present in 2.50 moles of H_2O?