2. Atoms & Elements

How many moles of water (H2O) are present in 75.0 g of H2O?

How many atoms of nitrogen are present in 10 g of NH_4NO_3?

Why do chemists use the mole as a unit in chemical calculations?

A student titrates 25.00 mL of HCl solution with 0.100 M NaOH. If it takes 32.50 mL of NaOH to reach the endpoint, how many moles of HCl were present in the original 25.00 mL of acid?

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

How many molecules are present in 25 grams of NH_3?

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?

In general chemistry, what does one mole represent?

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