The interior of the tanker car was washed out & cleaned with steam. Then all the outlet valves were shut and the tanker car was sealed. All the workers went home for the evening and when they returned, this is what they found that the tanker car was crushed. What was happening inside the tanker or outside the tanker than made it crush?

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante