Ihave no idea what this question is talking

ethanol contains the elements carbon, hydrogen, and oxygen. when ethanol burns, it chemically reacts with oxygen gas.

c2h6o + o2
ethanol oxygen gas

what elements will be present in the substances that are created when ethanol burns?

a. nitrogen, sulfur, and sodium only
b. carbon, hydrogen, and oxygen only
c. carbon and hydrogen only
d. the elements cannot be determined

Starch and are common polysaccharide carbohydrates found in plants. sucrose glycogen fructose cellulose

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Which property of a rock remains unchanged by mechanical weathering? a. total surface area b. size and shape c. mineral composition d. sharpness