Anybody know this it should be easy but i dont understand

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

In science class richard learns that a substance has a boiling point of 230 fahrenheit his teacher ask him to convert this temperature to degrees celsius what is the boiling point of his substance in degrees celsius

In ccl4 is there a certain length that the main atom carbon is a certain distance from the chlorine’s?