The combustion of methane gives carbon dioxide and water.
CH4 + O2 --> CO2 + H2O
For state symbol of water, is it liquid state or gaseous state?
It could be either, but in most situations, it will be water vapor (g) as the heat released will be sufficient to put it in the vapor state.
To determine the state symbol of water in the given reaction, we need to consider the conditions under which the combustion of methane typically occurs. Generally, combustion reactions take place at high temperatures, which cause substances to transition into their gaseous states.
In the equation you provided, the reactants are methane (CH4) and oxygen (O2), both of which are in their gaseous states. The products, carbon dioxide (CO2) and water (H2O), are usually in their gaseous states too because combustion reactions involve the release of heat.
However, once the combustion products cool down, water (H2O) can condense into its liquid state. Therefore, the state symbol for water in the given reaction is typically represented as a gas (g) but can ultimately transition into a liquid (l) under appropriate conditions.