What are good sources for chemistry

The reaction q+r2=r2q is found to be first order in r2 and

Why do lunar and solar eclipse not happen every month

What is the importance of interlocking the fingers and rubbing while washing hands? the palms are the dirtiest parts of the hands. the spaces between the fingers get washed. the backs of the hands get washed. the fingernails are the dirtiest parts of the hands