Held constant, the pressure and volume of gas . its from boyle's law

Answer : When temperature is held constant, the pressure and volume of gas are inversely proportional.

Explanation :

Boyle's law : It is defined as at constant temperature and amount of gas remains unchanged, the pressure of the gas is inversely proportional to the volume of the gas.

Using ideal gas law equation :

where,

P = pressure of the gas

V = volume of the gas

n = number of moles of the gas

T = temperature of the gas

R = gas constant

At constant temperature and amount of gas remain unchanged, the ideal gas represented as,

where, k is constant.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.