Conservation Of Mass And Balanced Chemical Equations (GCSE Chemistry)

Which statement best describes the law of conservation of mass in a chemical reaction?

Ammonia (NH3) reacts with oxygen to make nitric oxide and water: 4 NH3 + 5 O2 ? 4 NO + 6 H2O. How many moles of O2 are needed to react with 2.0 mol NH3?

If 2.00 g of hydrogen reacts with 16.0 g of oxygen to form water, which reactant is the limiting reagent? (Mr H2 = 2.0, O2 = 32.0)

When 100 g of calcium carbonate (CaCO3) decomposes completely to calcium oxide (CaO) and carbon dioxide (CO2) in a closed container, the mass of the products will be:

Balance the redox equation by inspection: Fe2O3 + C ? Fe + CO. The coefficient for C is:

Which shows the correct mole ratio in the balanced equation: 2 Al + 3 Cl2 ? 2 AlCl3 ?

A solution contains 0.100 mol of HCl in 250 cm3. What is the concentration in mol/dm3?

What is the empirical formula of a compound that is 40.0% C, 6.7% H, 53.3% O by mass (approx)?

If a balanced equation gives a mole ratio 1:2:1 (A:B:C) and you start with 1.00 mol A and 5.00 mol B, which is limiting and how many moles of C form?

Which calculation gives the concentration (mol/dm3) if you have 0.0150 mol dissolved in 30.0 cm3 of solution?

If 0.250 mol of NaCl is dissolved in enough water to make 0.500 dm3 of solution, what is the concentration in mol/dm3?