Question

A mixture of gaseous reactants is put into a cylinder, where a chemical reaction turns them into gaseous products. The cylinder has a piston that moves in or out, as necessary, to keep a constant pressure on the mixture of 1 atm. The cylinder is also submerged in a large insulated water bath.

The temperature of the water bath is monitored, and it is determined from this data that 300KJ of heat flows out of the system during the reaction. The position of the piston is also monitored, and it is determined from this data that the piston does 316KJ of work on the system during the reaction.


a. Is the reaction exothermic or endothermic?

b. Does the temperature of the water bath go up or down?

c. Does the piston in or out?

d. Does the reaction absorb or release energy?

e. How much energy does the reaction absorb or release? Round your answer to 3 significant

Answer 1

Step-by-step explanation:

a. The reaction is exothermic, since it releases heat (300 KJ that flow out of the system).

b. The water bath will receive the 300 KJ of heat that the system has released, therefore, its temperature will rise.

c. The pressure of the system is constant (1 atm) and its temperature goes down after the reaction, so the volume will decrease (according tho Charles' Law). Therefore, the piston will go in.

d. Since the reaction is exothermic, it releases energy.

e. The reaction releases 300 KJ of energy in the form of heat.