Final answer:
Combustion is the process that can turn 7 carbon atoms and 16 hydrogen atoms into useful energy, such as the energy used to propel a Jet Ski.
Step-by-step explanation:
The process that can turn 7 carbon atoms and 16 hydrogen atoms into useful energy, such as the energy used to propel a Jet Ski, is combustion. Combustion is a chemical reaction in which a fuel, like hydrocarbons, reacts with oxygen to produce heat and light. In this case, the carbon atoms and hydrogen atoms can combine with oxygen to produce carbon dioxide and water, releasing energy in the process.