What type of reactions are the following? ( single displacement, double displacement, synthesis, or decomposition) 4Mn3O4(s) + O2(g) -> 6Mn2O3(s)
Al2O3(aq) + 3C(s) ->3CO(g) + 2Al(l)
Ba(C2H3O2)2(aq) + Na2CO3(aq) -> BaCO3(s) +2NaC2H3O2(aq)
KOH(aq)+HBr(aq) -> KBr(aq)+H2O(l)

1. synthesis

2. single displacement

3.double displacement

4.double displacement

Explanation:

1. here Mangananes (iv) oxide further reacts with oxygen to form Manganese (iii) oxide , two reactants making one product .

2. Carbon replaces aluminium from aluminium oxide to make pure aluminium and carbon monoxide and carbon dioxide.

3. sodium replaces barium to make sodium acetate , barium replaces sodium to make barium carbonate ( precipitate )

4. potassium replaces Hydrogen to produce potassium bromide, while hydrogen and hydroxide ions combine to make water .

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.