In the late 1890s, what objection might have been raised about becquerel’s claim that the uranium salt crystals had emitted something that exposed the photographic film?
there was no apparent source for the uranium salts’ energy.

film only becomes exposed in response to light.

both the crystals and the film had been exposed to sunlight during the experiment.

the crystals began to phosphoresce in the drawer and release x-rays.

A- There was no apparent source for the uranium salts' energy (just took the edg test)

answer is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.