Stoichiometric problems

Calculate the number of O₂ molecules in 1.5 mol of oxygen (O₂).

• 9.0 × 10^23 molecules

• 0.9 x 10^23 molecules

• 9.0 molecules

• 32.00 g/mol

Calculate the number of mol of oxygen in 0.05 mol of O₂ molecules.

• 0.5 mol

• 1 mol

• 0.05 mol

• 0.1 mol

Calculate the relative formula mass (molar mass) of Vitamin C: C₆H₈O₆

• 29 g/mol

• 276 g/mol

• 176 g/mol

• 3 g/mol

Calculate the amount in mol of 1.2g of Nitric Oxide (NO)

• 0.04 mol

• 0.08 mol

• 1.2 mol

• 12 mol

Determine the % composition by mass of potassium in KNO₃

• 38%

• 100%

• 30%

• 20%

Calculate how many atoms are there in 5 moles of sulfur atoms.

• 1.20 x 10²³

• 6.02 x 10²³

• 6.02 x 10¹¹⁵

• 3.01 x 10²⁴

Which of the following is not the same number as the rest?

• The number of molecules in 4 moles of CO₂

• The number of hydrogen atoms in 2 moles of H₂O

• The number of chloride atoms in 4 moles of CaCl₂

• The number of hydrogen atoms in 0.5 mole of C₃H₈

The number of atoms present in 0.10 mol of ethene (C₂H₄) is

• 3.61 x 10²²

• 6.02 x 10²²

• 3.61 x 10²³

• 6.02 x 10²³

One mole of water contains

• 6.02 x 10²³ atoms of hydrogen

• 2.01 x 10²³ atoms of oxygen

• 6.02 x 10²³ atoms in total

• 6.02 x 10²³ molecules of water

The molar mass of iron(III) sulphate , Fe₂(SO₄)₃ will be

• 191.76 g mol^-1

• 207.76 g mol^-1

• 344.03 g mol^-1

• 399.88 g mol^-1