2. Atoms & Elements

How many moles are present in 22 grams of argon (Ar)? (Atomic mass of Ar = 39.95 g/mol)

Which of the following correctly reflects Avogadro's number?

A solution is prepared by mixing 50.0 g of benzene (C6H6) and 50.0 g of toluene (C7H8) at 25°C. The vapor pressures of pure benzene and pure toluene at this temperature are 95.1 mmHg and 28.4 mmHg, respectively. Assuming ideal behavior, what is the mole fraction of benzene in the vapor above the solution?

How many hydrogen atoms are present in 2 moles of H_2O?

In one mole of Be(OH)_2, how many moles of each element (Be, O, and H) are present?

How many moles of aluminum are present in 3.2 × 10^{25} atoms of aluminum?

How many moles are present in 4.9 \times 10^{23} molecules of CO_2?

Approximately how many particles are present in 2 moles of a substance?

Why is the concept of moles important in chemistry?

How many moles of sulfur atoms are present in 64 g of S_8?

How many moles of nitrogen atoms (N) are present in 0.231 g of N_2O?

How many moles of atoms are present in 9.00 g of 13C?

How many atoms are present in 1 mole of carbon?

Which statement best describes a mole in chemistry?

How many atoms are present in 135 g of calcium (Ca)? (Atomic mass of Ca = 40.08 g/mol)