How many grams are in 68.2 molecules of br2?

68.2 molecules of bromine gas weigh's

Explanation:

Number of molecules = 68.2

Number of molecules = Moles of × Avogadro number

Molar mass of the gas:

68.2 molecules of bromine gas weigh's

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.