What’s the first step that must occur in the mechanisms of the nucleophilic substitution reactions of 1-butanol or 2-methyl-2-butanol?

The minerals found in bones are deposited by living cells called

Mary is conducting an experiment on how pollution affects plant growth. how can she ensure that her data are reliable?

Asample of hydrated tin (ii) chloride (sncl2) has a mass of 4.90 g. when it is dehydrated, it has a mass of 4.10 g. which is the correct chemical formula for the hydrate? sncl2•2h2o          sncl2•4h2o          sncl2•6h2o