IGCSE Chemistry Whistlestop

What is the concentration of the solution produced by adding 0.30 mol of NaCl to 0.25 dm³ of water?

Ans = _._ mol/dm³

What is the atomic number of this element?

Empirical formula is the simplest _____ ______ _____ of atoms in a compound.

In the experiment to find the empirical formula of magnesium, why must we lift the lid of the crucible when magnesium burns?

• To allow MgO smoke out of the crucible

• To ensure that we heat to constant mass

• To check that there is a glow of burning magnesium

• To allow oxygen to enter the crucible

Why, when reducing copper oxide as above, should we run the gas through before lighting it?

• To remove oxygen from the tube & prevent the risk of an explosion

• To prevent the oxidation of the copper

• To reduce the copper oxide

• To ensure the copper does not reoxidise

What is the volume of 0.125 moles of carbon dioxide in cm³?

The definition of an acid: an acid is a ______ donor

Base + acid -->

• salt + hydrogen

• metal oxide + hydrogen

• salt + water

• salt + water + carbon dioxide

Which one of these compounds, when reacted with sulphuric acids, reacts quickly initially then stops?

• Copper oxide

• Aluminium

• Copper carbonate

• Calcium carbonate

The equation H⁺(aq) + OH^-(aq) --> H₂O is the ionic equation for ______________