2. Atoms & Elements

Why is the mole an important unit to chemists?

The mass of a mole of carbon atoms is 12.011 grams. What is the mass of a single atom of carbon?

How many moles of iron (Fe) are present in 279 g of iron? (Molar mass of Fe = 55.85 g/mol)

If you have 92 grams of nitrogen dioxide (NO_2), how many moles of NO_2 are present?

How many carbon atoms are present in 5 moles of ethane (C_2H_6)?

In chemistry, what does a mole measure?

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?