Put the following compounds in increasing atomic mass with the lowest mass at the top, and the greatest atomic mass at the bottom CaCO3
NaCl
CH3COOH
H2O

he would use the colour black

the answers would be

the first one and the second one

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.