Answer:
Chemical reactions make and break the chemical bonds between molecules, resulting in new materials as the products of the chemical reaction.
Explanation:
Breaking chemical bonds absorbs energy, while making new bonds releases energy, with the overall chemical reaction being endothermic or exothermic.
Calcium iodide (chemical formula <span>CaI2</span>)
Answer:
a. 
b. 
c. 
Explanation:
Hello,
a. By applying the given information, one obtains:

b. By knowing that the propane has a molecular mass of 44g/mol, one obtains:

c. Here, the propane's combustion chemical reaction is stated:

This enthalpy of reaction is computed via:
Δ
Finally, since it is done for 20 lb of propane (
), the obtainable energy is:

Best regards.
If all plate motion stopped, Earth would be a very different place. The agent responsible for most mountains as well as volcanoes is plate tectonics, so much of the activity that pushes up new mountain ranges and creates new land from volcanic explosions would be no more. The volcanoes of the Pacific Ring of Fire, in South and North America, Japan, the Philippines, and New Zealand, for example, would shut off, and the steady southeastward migration of volcanic activity along the Hawaiian Islands would stop. Volcanism would just continue on the big island. There would also be far fewer earthquakes, since most are due to motion of the plates.