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 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 133.0 kJ of heat flows into the system during the reaction. The position of the piston is also monitored, and it is determined from the data that the piston does 241.0 kJ of work on the system during the reaction.1) Does the temperature of the water bath go up or down?2) Does the piston move in or out?3) Does heat flow into or out of the gaseous mixture?4) How much heat flows?

Answer 1

Answer:

1) The temperature of the water bath goes down

2) The piston moves in

3) The heat flow into the gaseous mixture

4) +133.0 kJ of heat flows

Explanation:

1) The heat flows from the lowest temperature to the highest to the substances to reach the thermal equilibrium (same temperature). The gaseous mixture is the system, where the reaction is taking place, and the water bath is the surroundings. So, if the heat flows from the water to the system, it means that the water is at a higher temperature, so in the process, its temperature goes down to achieve the thermal equilibrium.

2) The piston does work on the system, so, the system is having its pressure increased by the reducing of its volume from the piston. It means that the piston is moving in the gaseous mixture.

3) As said above, the system is the gaseous mixture, and the heat is flowing from the surroundings to the system, so the heat flow into the gaseous mixture.

4) As the question said, the heat flow is +133.0 kJ.1) The heat flows from the lowest temperature to the highest to the substances to reach the thermal equilibrium (same temperature). The gaseous mixture is the system, where the reaction is taking place, and the water bath is the surroundings. So, if the heat flows from the water to the system, it means that the water is at a higher temperature, so in the process, its temperature goes down to achieve the thermal equilibrium.

2) The piston does work on the system, so, the system is having its pressure increased by the reducing of its volume from the piston. It means that the piston is moving in the gaseous mixture.

3) As said above, the system is the gaseous mixture, and the heat is flowing from the surroundings to the system, so the heat flow into the gaseous mixture.

4) As the question said, the heat flow is +133.0 kJ.