1. If a wave passes a point 4 times in one second traveling at 1200 m/s, what is the length of the wave? 2. What is the speed of a wave that is 35m long with a frequency of
100 Hz?

the answer to your question is c.

if you read the house of usher you should know that the house was haunted

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.