A graph titled position versus time has an horizontal axis time (seconds) and a vertical axis position (meters). A straight line passes from 0 seconds, 0 meters to 5 seconds, 20 meters. Calculate the slope of the line on the graph using the formula:

m = m = v subscript 2 - v subscript 1 over x subscript 2 minus x subscript 1.

The slope of the line is
m/s.

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.

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explanation:

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements

6.4 cm (max) - 25 cm (min)