What is the enthalpy for reaction 1 reversed? reaction 1 reversed: co2→co + 12o2?

CO2→CO + 12O2 is not a balanced reaction, I think you meant to post " CO2→CO + 1/2O2" The simple answer is that the enthalphy for reaction 1 reversed is the same enthalpy as for the reaction as written but with the opposite sign. If A + B = AB with 30 kJ released then AB = A + B with 30 kJ absorbed. We would write it as A + B = AB heat of reaction = -30 kJ AB = A + B heat of reaction = +30 kJ

Adozen is 12, and your needing to calculate the weight of one medium egg, so i would do 21/12=1.75 per egg, and check your answer by doing 1.75 * 12= 21 : ) : ): ): ): ) i hoped i

You would be correct, boiling water does disinfect contamination.    the property of disinfecting means to kill  germs, bacteria and other pathogens or contamination  that might cause an infection or cause a person to become sickly. a couple methods of disinfecting are using soap, other cleaning supplies or by simply "boiling" the contaminate.  the reason why boiling water disinfects certain attributes is because some cells cannot survive the heat and pressure.