Green plants use light from the sun to drive photosynthesis. photosynthesis is a chemical reaction in which water (h2o) and carbon dioxide (co2) chemically
react to form the simple sugar glucose (c6h206) and oxygen gas (o2).
what mass of oxygen gas is produced by the reaction of 9.8 g of carbon dioxide?

thats how its supposed to be

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.