A piston cylinder device contains 1 kg of oxygen at 150 kPa, 30°C. The cross-sectional area of the piston is 0.1 m2. Heat is now added causing gas to expand. When the volume reaches 0.2 m3, the piston reaches a linear spring with a spring constant of 120 kN/m. More heat is added until the piston rises an

You have not provided the complete question.But I think the rest is like that the spring is compressed by some distance and for which you then have to find the final temperature and the heat transferred.For this , the first process is isobaric process and heat transfer can be found out by nCp(delta T).As the spring is compressed by some distance you can calculate the final volume of the gas .For finding pressure, the increase from initial pressure will be equal to the extra pressure applied by the spring force.After this find the final temperature by using the ideal gas equation.