3B - Group 2

    1)           Write balanced chemical reactions, including state symbols for the following:

                            balancing [1]   state symbols  [1]

                    a)  Magnesium burning in air  [2]

                            2Mg_(s)    +    O_2(g)   à     2MgO_(s)

                    b)  Calcium in water  [2]

                            Ca_(s)    +    2H₂O_(l)   à     Ca(OH)_2(aq)      +    H_2(g)

                    c)  Magnesium oxide and hydrochloric acid  [2]

                            MgO_(s)    +    2HCl_(aq)   à     MgCl_2(aq)      +    H₂O_(l)

                    d)  Calcium oxide and water  [2]

                            CaO_(s)    +    H₂O_(l)   à     Ca(OH)_2(aq)

                    e)  Action of heat on calcium carbonate  [2]

                            CaCO_3(s)    à     CaO_(s)       +    CO_2(g)

    2)          For 1 (a) - (d) of the reactions above state any observations [6]

                    a)  Magnesium burning in air  [2]

                            Mg burns with a bright flame [1]    White powder formed  [1]

                    b)  Calcium in water  [2]

                            Calcium dissolves  [1]    Fizzing  [1]

                    c)  Magnesium oxide and hydrochloric acid  [1]

                            Magnesium oxide dissolves  [1]

                    d)  Calcium oxide and water  [1]

                            Calcium oxide dissolves  [1]

    3)          State and explain the trends in pH of the Group 2 hydroxides [3]

                            Down Gp2, pH increases [1] Due to the increase in solubility [1]

                            More free hydroxides dissolved [1]

    4)          State the trends in the decomposition of the Group 2 carbonates [1]

                            Down Gp2, harder to decompose [1]