Ok, I know how to balance chemical equations, however, I don't know how to tell if it is a S, L, aq, or g? How am I supposed to know this??

Mg(s)+AgNO3(aq)→Mg(NO3)2(aq)+Ag(s)
Express your answer as a chemical equation. Identify all of the phases in your answer.

Balanced equation would be :
Mg + Ag 2NO3--> Mg (NO3)2 +Ag
But what's the phases?

2 answers

Use the periodic table. There are 5 elements that are gases; H2, N2, O2, F2. Cl2 (plus of course the noble gases but we usually ignor those anyway). There are some common compounds that yu will learn as you go along; i.e., CO2, SO2, SO3, CO, NO, NO2, CH4(methane), C2H6(ethane), C2H4(ethene) and some others. Two liquids are Br2 and Hg. The rest are solids. Everything to the right of the "staircase of the elements" is a non-metal; everything to the left of that line is a metal. Those elements adjacent or on the line can act both ways.
k74sa