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) + O2(g) à 2MgO(s)
b) Calcium in water [2]
Ca(s) + 2H2O(l) à Ca(OH)2(aq) + H2(g)
c) Magnesium oxide and hydrochloric acid [2]
MgO(s) + 2HCl(aq) à MgCl2(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]
CaCO3(s) à CaO(s) + CO2(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]