2. Atoms & Elements

What is the numeric value of a mole for atoms or molecules?

What is the approximate combined mole fraction of N_2 and O_2 in Earth's atmosphere?

How many sulfur atoms are present in 5.325 × 10^{-23} grams of sulfur (atomic mass of S = 32.07 g/mol)?

Which of the following samples contains the greatest number of atoms?

How many atoms of Cl are present in 6.1 mol of CCl_4?

Which of the following best describes Avogadro's number?

Which of the following samples contains the same number of atoms as 1 gram of He?

The chemical standard for the quantity of a mole is based on which substance?

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

How many moles of CO_2 are present in a 220.-gram sample of CO_2, given that the gram-formula mass of CO_2 is 44 g/mol?

Which of the following steps correctly converts 18.0 grams of water (H_2O) to the number of molecules?

In the context of the mole concept, 12.0 grams of carbon-12 represents which of the following?

How many atoms are present in one mole of a substance?

How many carbon atoms are present in 1.00 mole of methane (CH_4)?

If you have 1 mole of NaCl, how many NaCl formula units does it contain?