A11.0-m by 6.0-m by 3.0-m basement had a high radon content. on the day the basement was sealed off from its surroundings so that no exchange of air could take place, the partial pressure of22rn was 1.3 x 10-6 mmhg. calculate the number of112rn isotopes (12-3.8 days) at the beginning and end of 28 days. assume stp conditions. t-0 days: x 10rn atoms 1-28 days: x 10rn atoms

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.

hypostyle hall;