2. Atoms & Elements

A 30. gram sample of neon (Ne) is given. What is the total number of atoms present in this sample?

In chemistry, what does a mole represent a count of?

How many molecules are present in 48.0 grams of NaOH?

How many molecules are present in 2.50 moles of H_2O?

How many hydrogen atoms are present in 4 molecules of H_2O?

If a sample of water contains 12 × 10^{23} oxygen atoms, how many moles of water molecules are present in the sample?

In the context of the mole concept, which statement best describes the role of baking soda (NaHCO_3) in mole calculations?

Magnesium and iron are metallic elements. How does a mole of magnesium compare with a mole of iron?

How many moles of cyclohexanone (molar mass = 98 g/mol) are present in a sample containing 147 g of cyclohexanone?

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?