2. Atoms & Elements

1. Why is the mole used as a unit in chemistry?

How many moles of KNO3 are present in 500.0 mL of a 2.0 M KNO3 solution?

How many molecules are present in 48.0 grams of oxygen gas (O_2)?

How many moles of hydrogen atoms are present in 135 mg of H_2O?

How many atoms of hydrogen (H) are present in 200 molecules of ammonia (NH_3)?

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

How many moles of KI are required to prepare 0.50 L of a 0.20 M aqueous solution?

How many moles of Pb are present in 4.71 × 10^{21} Pb atoms?

Based on the data provided in Table 1, which item contains the largest quantity of moles?

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

How many moles are present in 3.00 g of ethanol (C2H5OH)?

Which of the following is NOT equal to 1.00 mol of carbon-12?

How many molecules are present in 5.0 g of methyl alcohol (CH_3OH)? (Molar mass of CH_3OH = 32.0 g/mol)

How many atoms of hydrogen are present in 5.29 × 10^{21} molecules of ethanol (C_2H_5OH)?

How many atoms are present in 1.2 mol of carbon (C)?