Complete the statement.
During this chemical reaction, the air around the reaction becomes ().

 - colder
 - warmer
To determine whether the air around the reaction becomes warmer or colder, look for the text that describes the movement of thermal energy during the reaction.Some chemical substances explode under pressure. One such substance, nitrogen triiodide (NI3), explodes at even the lightest touch! When this happens, the nitrogen triiodide breaks down to form nitrogen (N2) and iodine (I2). During this reaction, chemical energy is converted to an enormous amount of thermal energy, which is transferred into the surroundings.The underlined text tells you that thermal energy is transferred into the surroundings. Because thermal energy moves out of the reaction and into the surroundings, the temperature of the surroundings increases.The surroundings include the air around the reaction. So, the air around the reaction becomes warmer.