Use a stem-and-leaf plot to display the data, which represent the thickness (in centimeters) of ice measured at 20 different locations on a frozen lake. Describe any patterns.

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.

some sources quote the lethal dose, for an average 170lbs opiate-naive individual is between 75 and 375 mg

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante