A mixture of gaseous reactants is put into a cylinder, where a chemical reaction tums 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 atmm. The cylinder is also submerged in a large insulated water bath. (See sketch at right.) 1 atm pressure piston cylinder The temperature of the water bath is monitored, and it is determined from this data that 300.1J 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 system does 316.kJ of work on the piston during the reaction water bath gases exothermic Is the reaction exothermic or endothermic? O endothermic Does the temperature of the water bath go up or down? o down O neither in o out O neither Does the piston move in or out? absorb O release O neither Does the reaction absorb or release energy? How much energy does the reaction absorb or release? Round your answer to 3 significant

A mixture of gaseous reactants is put into a cylinder, where a chemical reaction tums 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. (See sketch). The temperature of the water bath is monitored, and it is determined from this data that 300 kJ 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 system does 316 kJ of work.

Is the reaction exothermic or endothermic?

The reaction releases 300 kJ of heat, that is, q = -300 kJ. This means that the reaction is exothermic.

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

Since water absorbs the heat released by the system, its temperature goes up.

Does the piston move in or out?

The system does 316 kJ of work on the surroundings, that is, w = -316 kJ. This means that the gaseous mixture expands and the piston moves out.

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

The change in the internal energy (ΔU) is:

ΔU = q + w = (-300 kJ) + (-316 kJ) = -616 kJ

The system releases 616 kJ.