PLEASE URGENT! Which of the following substances have ΔH°f= 0?

O3(g) C2(g) Cl2(g) Mg(s) H2O(l)

When a spring is compressed, the energy changes from kinetic to potential. which best describes what is causing this change?

Which suspect most likely committed the robbery and how do you know

The human activities in two locations are described below: location a: rampant use of plastic containers location b: excessive use of pesticides and fertilizers which statement is most likely true? location a will have poor air quality because plastic is biodegradable. location a will experience water scarcity because plastic absorbs moisture. the population of honeybees will increase in location b because production of crops will increase. the population of fish in location b will decrease because the water is contaminated.