Identify the type of reaction, write the products with phases, and balance. show all work.

1) 2mg(s) + o2(> 2mgo (s)

2) na(s) + cl2(> nacl(s)

3). pbco3(> pbo(s)+co2(g)

4). ch4(g) + 2o2(> co2(g) + 2h2o(g)

The correct classification of the reactions are as follows:

1) 2Mg(s) + O2(g)> 2MgO (s)
It is a synthesis reaction or a combination reaction. It involves the bonding of the reactant molecules forming one single molecule with new set of properties.

2) Na(s) + Cl2(g)> NaCl(s)
It is a combination reaction as well, the same as the first reaction.

3). PbCO3(s)> PbO(s)+Co2(g)
It is a decomposition reaction where a single molecule is breaks down into multiple molecules.

4). Ch4(g) + 2O2(g)> CO2(g) + 2H2O(g)
It is a combustion reaction since it involves the reaction with oxygen and the production od carbon dioxide and water.

Well technically there are two correct answers b and d. but for you its probably b in general.good day sir/ma'am : ) (i know not gender)