A gas absorbs 10J of heat and is simultaneously compressed by a const and external pressure
of 0.5 atm from 4L to 2L in volume What
is the change in the internal energy.
A. 101J b. 111J c.2J d. none of the above

Given :

Heat absorbs , Q = 10 J .

Pressure ,

Initial volume , .

Final volume , .

To Find :

The change in the internal energy .

Solution :

By first law of thermodynamics :

Here , W is work done ,

Therefore,

Putting values in SI units in above equation :

Therefore , option b. is correct .

Hence , this is the required solution .

first, consult an activity series chart to determine if al is more reactive than fe. it is, so it will replace the fe. now, one can continue with the problem.

next, make sure you have a correctly balanced equation.

3feo + 2al ==> 3fe + al2o3

now, determine which reactant (feo or al) is in limiting supply.

moles feo present = 125 g x 1 mole/71.8 g = 1.74 moles

moles al present = 25.0 g x 1 mole/26.98 g = 0.927 moles

since from the balanced equation, it take 3 mol feo for every 2 mol al, al will be limiting.

you can determine this simply by dividing moles of each by their coefficient in the balanced equation. for example: 1.74/3 = 0.58 and 0.927/2 = 0.464. al is less, so it is limiting.

finally, using the stoichiometry in the balanced eq. determine mass of fe that can be produced from 0.927 moles of al.

0.927 moles al x 3 moles fe/2 moles al x 55.8 g/mole = 77.6 g

put the answers   and i could answer.