Why is mass conserved in a chemical change?
the energy used in the chemical reaction burns up the extra matter.
the compounds are still exactly the same, they just look different.
the atoms are still there, they are just rearranged to form new compounds
the new matter that is formed takes up the same volume as the original matter.

Alice did an experiment to find the relationship between the angle at which a ray of light strikes a mirror and the angle at which the mirror reflects the light. she placed a ray box in front of a mirror. she changed the angle at which the light from the ray box struck the mirror and noted the corresponding angle at which the mirror reflected the light. which of the following is the dependent variable in this experiment? the mirror used to reflect the light the ray box used as the source of light angle at which the light from the ray box strikes the mirror angle at which the mirror reflects the light from the ray box