urgent chem questions~

1. under standard conditions, complete combustion of 0.05mol of propane gives 111kJ of heat, cal the standard enthalpy change of formation of propane.
(standard enthalpy change of formation of H2O=-826kJmol-1
standard enthalpy change of formation of CO2=-394kJmol-1 )

2. scandium (Sc)is a metal, scandium in its compound exhibits only one oxidation number. the chemical formula of scandium nitrate is Sc(NO3)3
which of the following is most like to be the chemical formula of scandium phosphate?
A Sc2(PO4)3
B ScPO4
C Sc(PO4)2
D Sc(PO4)2

3. which of the following statements about the action of sodium hydroxide solution on ethanamide is/are correct?
(1) sodium ethanoate is formed in the reaction
(2)in the reaction, sodium hydroxide astc sd a catalyst
(3)the reactiom attains equilibrium if the reaction mixture is heated under reflux

A (1)only
B (2)only
C (1)and (3) only
D (2)and (3) only

4. Fe3+ + SCN- <----> Fe(SCN)2+
in the experiment, 25com3 of 0.01M Fe2(SO4)3 and 25cm3 of 0.01M KSCN were mixed in a conical flask at room temp, and equilibrium was attained
the conc of Fe(SCN)2+ in the mixture was 0.0043M when equilibrium was attained

(a)cal the eqilibrium constant Kc for the above reaction at room temp.

(b)it is known that FePO4 (s) is insoluble in water. suggest what would be the effect on the equilibrium position if Na3PO4 (s)is added to the equilibrium mixture.