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. 1 atm pressure piston cylinder From previous experiments, this chemical reaction is known to release 368. kJ of energy water bath gases The position of the piston is monitored, and it is determined from this data that the system does 125. kJ of work on the piston during the reaction exothermic 1. Is the reaction exothermic or endothermic?2. Does the temperature of the water bath go up or down? 3. Does the piston move in or out?4. Does heat flow into or out of the gas mixture?5. How much heat flows? Round your answer to 3 kJ significant digits

Answer 1

1. since energy is released int the water bath, then the reaction is exothermic

2. since energy is released into the water bath, the temperature of the water bath will go up.

3. the system does work on the piston, therefore, the piston will move out.

4 since the reaction is exothermic, heat will flow out of the system (gas mixture)

5. 493 kJ

Step-by-step explanation:

Exothermic reactions are those reactions that liberate heat to their surrounding. The reverse is an endothermic reaction. If energy is released into the surrounding environment (water bath in this case), then the temperature of the surrounding environment will go up.

A system does work on its environment by expansion of the gas within the cylinder, which forces the piston out. In the case where work is done on the system by the environment, the piston moves inwards due to the shrinking of the volume of the gas within it.

The gas mixture will lose heat since it reacts exothermically.

From thermodynamics,

Q = U + W

where

Q = total heat in the system

U = the internal energy of the system ( negative if exothermic) = -368 kJ

W = work done by the system (negative if work is done on the system) = -125 kJ

imputing values,

Q = -368 + (-125) = -368 - 125 = -493 kJ

the negative sign shows that 493 kJ of heat is lost from the system in total