Answer:
Final temperature of the gas is 576
.
Explanation:
As the amount of gas and pressure of the gas remains constant therefore in accordance with Charles's law:

where
and
are volume of gas at
and
temperature (in kelvin scale) respectively.
Here
,
and 
So
849 K = (849-273)
= 576 
So final temperature of the gas is 576
.
Homogeneous mixture because it contains the same properties as homogeneous