Allen is carrying out reactions in a lab. one of the products in all reactions is found to be either a precipitate, a gas, or water. what is common between all these reactions?

Here are some examples for those type of reactions.

Combustion reaction: CH4(g) + 2 O2(g) --> CO2(g) + 2 H2O(l)

Decomposition reaction: CaCO3(s) ---> CaO(s) + CO2(g)

Double replacement: AgNO3(aq) + NaCl(aq) ---> AgCl(s) + NaNO3(aq)

One common thing in all is that they are reactions. They have reactants to form new substances called product.

2.00 is the !