Please check this for me ASAP and help me solve the second one

Thank you so much!!!

In which reaction is precipitation occurring?

An object resting on a table weighs 100 n. with what force is the object pushing on the table? with what force is the table pushing on the object? explain how you got your answer.

How many moles of co2 are produced during the complete combustion of 3.6 moles of c2h6