Chemists use symbols and formulae to represent elements, ions and compounds. Word equations and balanced chemical equations represent the changes that happen in chemical reactions.
What is the correct symbol for the element copper?
Which of these elements exists as a molecule with two atoms joined together?
Sulfur dioxide is a compound that contains one sulfur atom and two oxygen atoms. What is the formula of sulfur dioxide?
Barium is in group 2 of the periodic table. What will be the charge on a barium ion?
Copper ions have a 2+ charge and hydroxide ions have a 1- charge. What is the formula of copper hydroxide?
Aluminium chloride has the formula AlCl3. What is the Mr of aluminium chloride? (Atomic masses: aluminum = 27, chlorine = 35.5)
The diagram shows a CFC molecule. CFCs are compounds that can be used as refrigerants. What is the empirical formula of this CFC?
Which of these represents a solution of sodium chloride in water?
Which of these equations is balanced?
CH4 + 2O2 → CO2 + 2H2O
CH4 + O2 → CO2 + 2H2O
CH4 + 3O2 → CO2 + 4H2O
Which of these equations shows the formation of a precipitate of copper carbonate from copper ions and carbonate ions? - Higher
2Cu+(aq) + CO32-(aq) → CuCO3(s)
Cu2+(aq) + CO3-(aq) → CuCO3(s)
Cu2+(aq) + CO32-(aq) → CuCO3(s)