Answer:
Ca
Explanation:
It is on the left side of the periodic table where metals are located.
Answer: The final temperature in Kelvin is 1488
Explanation:
To calculate the final temperature of the system, we use the equation given by Gay-Lussac Law. This law states that pressure of the gas is directly proportional to the temperature of the gas at constant pressure.
Mathematically,

where,
are the initial pressure and temperature of the gas.
are the final pressure and temperature of the gas.
We are given:

Putting values in above equation, we get:

Hence, the final temperature in Kelvin is 1488
Explanation:
It is known that 1 SCF produces approximately 1000 Btu of thermal energy.
As it is not mentioned for how many hours the gas is used in this process. Therefore, we assume that the total number of hours natural gas used in this process are as follows.
= 8760 hours
Now, we will calculate the annual cost of natural gas used in the process as follows.

= 555384000 SCF
Hence, annual cost of natural gas used in this process = loss of thermal energy
This will be equal to, 
= 555,384,000,000 BTU
Thus, we can conclude that the annual cost of natural gas used in the process is 555,384,000,000 BTU.