When we combined baking soda and vinegar in a closed jar and lid had the same mass before and after they were combined and mixed together. what law best explains this result

The law of conservation of mass. 

Hope this helps!

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.