What is the most likely reason it is dangerous to break open a compressed gas tank?

Extreme pressure of the gas exerted on the walls of tank or cylinder is most likely the reason

Explanation:

Normally, compressed gas is filled in a container at a high pressure, because there is no other method you can fill a gas in this container. You need a greater quantity of gas filled in container and then transported to other places for various purposes. Now usually a valve is placed at the opening of tank or cylinder to control the flow of gas when using it. If you break open the container, the gas molecules will break out at a rapid velocity, since, according to Newton's third law of motion, which is,

Every action has an equal but opposite reaction

the force exerted by gas to flow out into atmosphere will equally act on container as well but in opposite direction. It can cause container to move haphazardly in very fast speed and container can collide with you or any other person standing nearby.

Secondly, it depend upon the nature of gas that it is might be poisonous or inflammable  and when breaks out in environment, it can cause damage to the people who inhale it or it might cause fire in the surroundings. That is why, it is dangerous to break open a container of compressed gas.

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.

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