Which of the following CANNOT be determined by looking at the spectra of a star? * A:temperature
B:composition (the elements that make up the star)
C:movement toward or away from Earth
D:distance from Earth

A:temperature

Explanation:

The temperature cannot be determined by looking at the spectra of the star due to lack of the equipment for its measurement. On the other-hand, the remaining statements like the distance from earth, movement towards or away from earth can be determined.

the law of conservation of mass states that in a chemical reaction, the total mass of reactants is equal to the total mass of products. because atoms are only rearranged in a chemical reaction, there must be the same number of sodium atoms and chlorine atoms in both the reactants and products

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.