How much more mass does carbón -14 have compared to carbón -12

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?

One nanometer is equal to how many meters?

2-bromo-2-methylbutane undergoes an e1 elimination reaction in the presence of ethanol. in the next reaction only one of the possible products is represented. although the product shown is not the major product of the reaction, notice that there is more than one way it can be produced. complete the mechanism and draw the missing substances.