Which type of reaction is 2c2h6 + 7o2 → 4co2 + 6h2o? a. decomposition reaction b. synthesis reaction c. combustion reaction d. double-replacement reaction

C) Combustion reaction.

Explanation: a combustion reaction is an exothermic reaction in which something reacts with oxygen. The combustion of organic compounds usually takes the form: organic compound + oxygen => water + carbon dioxide. As we can see the given reaction is an organic compound (C2H6) plus oxygen (O2) and the products are carbon dioxide (CO2) and water (H2O), so it is a combustion reaction.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.