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) Temperature of the water bath rises

2) the piston moves out

3) 133 kJ of heat flows

Explanation:

Given:(Isobaric process)

• Heat absorbed by the system,$Q_{in}=133000\ J$

• work done on the system, $W=241000\ J$

• pressure on the system, $P=1\ atm=101325\ Pa$

1)

Since the whole setup is isolated and the heat is absorbed by the system therefore the the temperature of the water will go down.

2)

When the system absorbs heat its pressure has to be constant so the piston needs to move up outwards giving the inside gases more volume.

As ideal gas law equation:

$P.V=m.R.T$

$P=$absolute pressure of the gas

$V=$ volume of the gas

$m=$ mass of the gas

$R=$ universal gas constant

$T=$ absolute temperature of the gas

Since pressure, mass and gas constants are the constant value we observe that: $T\propto V$

3)

According to the given data the heat that flows is 133 kilo-joule in quantity.