The goal of this experiment was to answer the question, "How does diffraction occur?" Suppose you formulated
this alternate hypothesis:
If the gap width is increased while keeping wavelength
constant, then the observed diffraction will decrease
because the less the ratio between wavelength and gap
width is, the smaller the observed diffraction angle will
be.
To test this hypothesis, you would change the
and observe the
in the system.
Therefore, the independent variable would be the
and the dependent variable would
be the

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.

gasoline is a mixture. it contains several different kinds of compounds that can be present in a variety of ratios.