Question

what are the matter inputs and outputs when we burned the ethanol? what is your evidence for this? ready? enter your answer here.

Explanation:

When ethanol (\(C_2H_5OH\)) burns, it undergoes a combustion reaction. The reactants (matter inputs) are ethanol and oxygen (\(O_2\)) from the air. The products (matter outputs) are carbon dioxide (\(CO_2\)) and water (\(H_2O\)). The chemical equation for the complete combustion of ethanol is \(C_2H_5OH + 3O_2\xrightarrow{\text{burning}} 2CO_2 + 3H_2O\). Evidence for this comes from observing the reaction: when ethanol burns, we can test for \(CO_2\) (e.g., using limewater which turns cloudy) and \(H_2O\) (e.g., seeing condensation on a cool surface held above the flame), and we know oxygen is consumed as the fire needs air (oxygen) to burn, and ethanol is the fuel being burned.

Answer:

• Matter Inputs: Ethanol (\(C_2H_5OH\)) and oxygen (\(O_2\)) (from the surrounding air).
• Matter Outputs: Carbon dioxide (\(CO_2\)) and water (\(H_2O\)) (released as gas and vapor, respectively).
• Evidence:
• For \(CO_2\): Bubbling the combustion gas through limewater (\(Ca(OH)_2\)) causes it to turn cloudy (precipitation of \(CaCO_3\)), confirming \(CO_2\) is produced (\(CO_2 + Ca(OH)_2 = CaCO_3\downarrow + H_2O\)).
• For \(H_2O\): Holding a cool, dry surface (e.g., a glass slide) above the flame shows condensation (liquid water), proving \(H_2O\) vapor is produced.
• For oxygen consumption: The flame requires air (containing \(O_2\)) to sustain combustion, and the ethanol (fuel) is visibly consumed during burning. The chemical equation \(C_2H_5OH + 3O_2\xrightarrow{\text{combustion}} 2CO_2 + 3H_2O\) also supports the stoichiometry of reactants and products.