Answer:
![dQ=-500J](https://img.qammunity.org/2021/formulas/physics/high-school/hsnntkh2l8zt4t20jlcosbgxnway3taf2l.png)
Step-by-step explanation:
We have given work is done on the gas is 1200 J
So work done will be
( as work is done on the gas )
It is given that internal energy is increases by exactly 700 J
So
![dU=700J](https://img.qammunity.org/2021/formulas/physics/high-school/4bek9nl9ovmaek2hvwtp5ezpks1xgakl4w.png)
From thermodynamic equation
![dQ=dU+dW](https://img.qammunity.org/2021/formulas/physics/high-school/fqtrgd3wvgqmdq59of2nvgi55js7286pka.png)
So
![dQ=700-1200=-500J](https://img.qammunity.org/2021/formulas/physics/high-school/ghemely33unt3p3sirv5ge8nsh04fyklfv.png)
Here negative sign indicates that heat flow out of the gas
If heat was negative then heal was flowing in the gas