Which of the following is a chemical change?

A. making a snowman
B. melting gold
C. cutting a rope
D. burning sugar
E. bending a steel rod

Which substance absorbs 58.16 kj of energy when 3.11 mol vaporizes? a)ch4 b)h2s c)co2 d)nacl

Idon’t know how to solve this question

If one fission reaction of a uranium-235 atom produced two neutrons, how many neutrons would be released if the chain reaction occurred three more times?