Water boils at 100 ˚c at atmospheric pressure, i. e. at sea level (101,325 pa). the boiling point is defined as the temperature at which the vapor pressure of water is equal to the atmospheric pressure. this has consequences for cooking in places like denver and santa fe where it takes quite a bit longer to make a hard-boiled egg than it would in new york. if the vapor pressure of water obeys the antoine equation (below), and the albumen in an egg needs to reach 90 ˚c for the protein to coagulate, at what height would it be impossible to hard boil an egg?

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.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.