In calculating density for an unknown sample, we must divide its mass, 294.37 g, by its volume, 87 mL. What is the correct density of the mineral calculated using rules you learned for multiplying and dividing with significant figures?

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.

the answer is option a.