Question

A chemical reaction occurs in a flask with an attached syringe the reaction absorbs 150 J of energy and as 25J of work on the syringe. Calculate the change in energy in joules of the system. Write the missing numbers in the boxes to complete the equation Q+W=

Answer 1

Answer: 175 J

Step-by-step explanation:

According to first law of thermodynamics:

`\Delta E=Q+W`

`\Delta E`=Change in internal energy

Q = heat absorbed or released

W = work done or by the system

W = work done on the system=
`-P\Delta V` {Work done on the system is positive as the final volume is lesser than initial volume}

w = + 25 J

q = + 150 J {Heat absorbed by the system is positive}

`\Delta E=+25J+(+150)J=+175J`

Thus Q+W= +175 J