2. Atoms & Elements

Approximately how many atoms of carbon are present in a 120 gram sample of carbon (assume the sample is pure \(^{12}\)C)?

A small lead block has a mass of 6.8 g. How many atoms of lead (Pb) are present in the block? (Atomic mass of Pb = 207 g/mol, Avogadro's number = 6.022 × 10^{23} mol^{-1})

How many moles of Kr are present in 398 mg of Kr? (Molar mass of Kr = 83.8 g/mol)

How many atoms are present in a sample containing 4.000 moles of carbon?

How many atoms are present in 6.25 moles of chromium (Cr)?

What is the total number of moles of NaCl(s) required to prepare 3.0 liters of a 2.0 M NaCl solution?

Why is the mole used as a unit in chemistry?

Given 60.0 grams of NaOH and 2.73 grams of NH4Cl, which of the following correctly represents the number of moles of each substance?

How many particles are present in 1 mole of a substance?

How many molecules are present in 4 moles of ammonia (NH_3)?

What is the number of atoms in one mole of any element?

How many moles are present in 100.0 g of water (H_2O)?

How many formula units are present in 3.4 moles of NaOH?

How many moles of solute are present in 500 mL of a 1 M solution?

Which of the following samples of N_2 contains the greatest mass?