Show that the units of kinetic energy (from ½ mv2 ) and gravitational potential energy (from mgh) are the same.

The units of both types of energy are Joule (kg × m² × s⁻²).

Explanation:

Step 1: Show the units of kinetic energy

The equation for kinetic energy is:

K = 1/2 × m × v²

where,

m: mass

v: speed

The units are:

K = 1/2 × m × v²

[K] = kg × (m/s)²

[K] = kg × m² × s⁻² = J

Step 2: Show the units of gravitational potential energy

The equation for gravitational potential energy is:

G = m × g × h

where,

m: mass

g: gravity

h: height

The units are:

G = m × g × h

[G] = kg × m/s² × m

[G] = kg × m² × s⁻² = J

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.