Chemical Formulae, Equations, the Mole and Gases

Which equation is balanced?

Which sample contains the greatest number of atoms? (A_r: H 1.0, He 4.0, N 14.0, O 16.0)

2.0 mol of N₂ reacts with 3.0 mol of H₂: N₂ + 3H₂ → 2NH₃. What is the greatest amount of NH₃ that can form?

What volume of carbon dioxide, measured at room temperature and pressure, forms when 0.10 mol of propane, C₃H₈, burns completely?

Under which conditions does a gas behave most like an ideal gas?

Convert into SI units.

The relative atomic mass of naturally occurring chlorine is not a whole number. What is the reason for this?

The element thallium, Tl, has only two isotopes with mass numbers 203 and 205. The relative abundance of Tl-203 is 30%. Which of the following is the relative atomic mass of thallium?

A giant molecule contains a large amount of carbon-12 and carbon-13 isotopes. The average relative atomic mass of carbon in the giant molecule is 12.2. What proportion of carbon-12 atoms is present in the giant molecule?

Element V has 14 neutrons and 13 protons, while element W has 10 neutrons and 9 protons in its nucleus. What would be the molar mass of the compound formed between V and W?

The rate of diffusion of two gases, methane, CH₄, and propene, C₃H₆, is investigated. Which gas diffuses at a faster rate and why? Each option gives the faster gas, then the reason.

Which substance has 7.2 × 10²³ atoms?

An element forms a diatomic molecule, Q, which has a relative molecular mass, x. The Avogadro constant is L. How many atoms are present in 1.0 g of Q?

A black solid, X, is an oxide of ruthenium. 5.79 g of X contains 1.39 g of oxygen. What is the empirical formula of X?

Aerials in portable radios are made of a mixture of the oxides of calcium and iron known as ‘ferrite’. It contains 18.5% calcium and 51.9% iron by mass. Which is the empirical formula of ‘ferrite’?

The relative molecular mass, M_r, of liquid Z is 60. Z contains 40.0% carbon, 6.70% hydrogen and 53.3% oxygen. Which row shows the correct empirical and molecular formulae of Z?

On complete combustion, a sample of hydrocarbon gives 11.0 g of carbon dioxide and 9.0 g of water. What is the molecular formula of the hydrocarbon?

When 4.8 g of magnesium is heated in a crucible, 5.9 g of magnesium oxide is formed. What is the percentage yield of magnesium oxide?

Ammonia and excess carbon dioxide can react to form urea and water: 2NH₃ + CO₂ → CON₂H₄ + H₂O. The percentage yield of this reaction is 80%. What mass of ammonia is required to obtain 60.0 g of urea? [M_r: NH₃ 17, CO₂ 44, CON₂H₄ 60, H₂O 18]

When 42.0 g of sodium hydrogencarbonate, NaHCO₃ (M_r = 84), was strongly heated, 3.00 dm³ of carbon dioxide gas, measured at room temperature and pressure, was released. 2NaHCO₃ → Na₂CO₃ + H₂O + CO₂. What was the percentage yield of carbon dioxide?

What is the concentration of iron(III) ions in 0.01 mol/dm³ of aqueous iron(III) sulfate?

28 g of gaseous hydrocarbon X has a volume of 12 dm³ at room temperature and pressure. What is the molecular formula of X?

Which fuel produces 144 dm³ of carbon dioxide, measured at room temperature and pressure, upon complete combustion?